This Page Contains Short Articles On Diet, Exercise, Fitness And Health

Here is a list of the blogs that I have posted on this page so far. I'll be adding more in the coming months

Blog #1: How To Achieve A Healthy Diet

Blog #2: Tips For Losing Weight By Dieting And Some Things To Help Abate Your Hunger

Blog #3: Exercise For Weight Loss: What Sort Of Exercise Is Best For Burning Fat?

Blog #4: What Is A Low Energy Density Diet And Why Is It Good For Weight Loss?

Blog #5: Intermittent Fasting Diets

Blog #6: Effects Of Exercise On Immune Function And Risk Of Infections

Blog #7: Reducing Your Risk Of Picking Up Common Infections

Blog #8: Are The Claims About Superfoods For Real?

Blog #9: What Are The Potential Benefits Of Taking Probiotic Supplements?

Blog #10 Physiological And Metabolic Demands Of Tennis

Blog #11: Coffee Makes Exercise Feel Easier

Blog #12: Why Type 2 Diabetes Is The Major Disease Of The 21st Century

Blog #13: Eating A Diet For Optimal Health Does Not Have To Be Complicated

Blog #14: How Much Protein Should People Eat?

Blog #15: Do I Need To Take Any Supplements?

Blog #16: What You Can Eat And Do To Avoid The Coronavirus

Blog #17: Lifestyle behaviours to beat COVID-19 and improve your vaccination response

Blog #1: How To Achieve A Healthy Diet

All of us should want to remain healthy – in both the short and long term – and getting the right amount of essential nutrients (like protein, vitamins and minerals) and nonessential but health-promoting nutrients (like fiber and phytonutrients) while avoiding an excess of energy (calories) is crucial to this goal so it is important to understand the basis of a healthy diet. This blog examines how people can achieve a healthy diet through appropriate food choices and eating to maintain energy balance and avoiding excesses. The content of this blog is an adapted excerpt from my new healthy lifestyle guidebook “Eat, Move, Sleep, Repeat” which is being published by Meyer & Meyer. The book will be available for delivery in January 2020 and you can pre-order your copy from Amazon now via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_1?crid=1R3EQI16R1CCN&keywords=eat+move+sleep+repeat&qid=1561723790&s=gateway&sprefix=eat+move+%2Caps%2C139&sr=8-1

We all need certain amounts of energy and specific nutrients in order to survive and be healthy. We need energy from the food we eat to maintain our bodies and to be able to move. The main energy sources in our diet are carbohydrates and fats. We need protein to which enables our cells to divide, grow, develop, and function. And we need vitamins and minerals which play numerous vital roles in the body. They are needed for bone structure, nerve transmission, oxygen transport, wound healing, and immune function. They are also involved in metabolism and are needed for the function of many enzymes including those that convert food into energy, synthesize new molecules, and repair cellular damage. However, even if we consume adequate amounts of essential nutrients, this in itself does not guarantee the absence of potentially harmful effects on our health in relation to the food that we consume. Eating too much of some nutrients (e.g., carbohydrates, fats), or certain subgroups of nutrients (e.g., simple sugars, corn syrups, saturated fats, trans fatty acids), and other nonessential nutrients (e.g., alcohol, salt) can have harmful effects on our health. These effects may not always be obvious in the short term (i.e., days, weeks, or months), but in the long term (i.e., years), excess intakes increase our risk of developing chronic metabolic and cardiovascular diseases and cancer. Consuming sufficient vitamins and certain minerals is essential for good health, but consuming too much of high dose (megadose) supplements actually will have negative health effects. Also, deficiencies of some of the nonessential nutrients (e.g., fiber, phytonutrients) can mean that our diets will not deliver what we need for optimal function and health.

General guidelines for healthy eating include balancing food intake with physical activity to maintain a healthy body weight; eating a wide variety of nutrient-rich and nutrient-dense foods; eating a diet rich in vegetables, fruits, whole-grain foods, and high-fiber foods; selecting a diet that is moderate in total fat but low in saturated fat, trans fat, and cholesterol; cutting back on beverages and foods that are high in energy but low in nutrients; consuming less sugar; using less sodium and salt; drinking alcohol in moderation; practicing food hygiene and safety; and avoiding excessive intake of food additives and supplements.

Recently introduced updated dietary guidelines from several countries including the US, UK and Australia focus on advice about consuming recommended portions of various food groups and shifting food choices to healthier options. The overall aim is to achieve adequate intake of essential nutrients while meeting (but not exceeding) energy requirements. Most guidelines now also encourage increased physical activity. These guidelines are often quite detailed and there is a lot of information to take in making it difficult for people to follow the well-intentioned advice provided. In order to emphasize some of the more important points I have condensed this information into ten top tips for eating a healthy diet as follows:

Ten top tips that summarize how to achieve a balanced healthy diet:

1. Eat meals at regular times of the day. Don’t skip breakfast, and don’t eat snacks between meals.

2. Eat at least five portions of a variety of fruit and vegetables every day.

3. Try to choose a variety of different foods from the six basic food groups. That means including ones from the milk group (e.g., milk, cheese, yogurt), the meat group (e.g., meat, fish, poultry and eggs, with dried legumes and nuts as alternatives), fruits, vegetables, and the breads and cereals group and limited amounts of oils and fats.

4. The main source of energy for meals should come from potatoes, bread, rice, pasta or other starchy carbohydrates. Have only small to medium portions of these, and choose wholegrain or higher-fiber produce where possible.

5. Choose lower-fat and lower-sugar options where available for things like dairy products, coleslaw, yogurts etc.

6. Eat some beans, pulses, fish, eggs, meat, and other high-protein foods. Aim for two portions of fish every week, one of which should be oily, such as salmon or mackerel.

7. Choose unsaturated oils and spreads, but only eat them in small amounts.

8. Drink plenty of fluids (six to eight cups or glasses per day are recommended), particularly water (plain, mineral or soda), low-calorie (diet) versions of popular beverages (e.g., cola, lemonade and tonic water), and fruit juices with no added sugar. Tea and coffee are also fine in moderation but if you like them to taste sweet use an artificial sweetener rather than sugar.

9. Limit your intake of alcohol by drinking no more than one 175 mL glass of wine or 350 mL beer with your main meal of the day and only on three days of the week.

10. Try to limit foods and drinks that are high in fat, salt and sugar by having these less often and in small amounts.

Blog #2: Tips For Losing Weight By Dieting And Some Things To Help Abate Your Hunger

The following general tips about losing weight by dieting will help you successfully achieve weight loss. Some of these strategies will also help to abate your hunger when you are eating fewer calories than you are used to. The following is an adapted excerpt from my new healthy lifestyle guidebook “Eat, Move, Sleep, Repeat” which is being published by Meyer & Meyer in January 2020. The book can be ordered from Amazon now via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_1?crid=1R3EQI16R1CCN&keywords=eat+move+sleep+repeat&qid=1561723790&s=gateway&sprefix=eat+move+%2Caps%2C139&sr=8-1

Do not try to lose more than about 0.5-1.0 kg/week (about 1-2 lbs/week), and do not restrict dietary energy intake by more than 750 kcal/day on consecutive days.

Avoid snacking between your regular meals. If you really feel the need for a snack choose low-fat and low-carbohydrate food items; raw celery, cucumber, spring onion, shredded carrots and watermelon are excellent choices.

Study food labels and try to find substitutes for high-fat foods. Look not only at fat content but also at the added sugar and energy content per serving.

Try using a smaller diameter plate; for example use one that is 23 cm (9 inches) in diameter rather than the usual 28 cm (11 inches).

Drinking a glass or two of water or a low calorie beverage before eating a meal is a good idea as it makes the stomach feel fuller quicker. Dehydration can be a problem when dieting because many of the foods you normally eat contain water. When dieting try to ensure that you drink at least two liters of water or low calorie beverages per day to keep well hydrated.

Limit fat add-ons such as sauces, sour cream, coleslaw and high-fat salad dressings, or choose the low-fat versions of these products. Better still, use a sprinkle of dried mixed herbs, chili bits, curry powder, ground pepper, garlic granules, ginger or paprika to your meals to add extra flavor without the calories.

Add some beetroot, beansprouts, pickled onions, red cabbage or sauerkraut to your main meals for added bulk, fiber and flavor (as illustrated in the accompanying photo). These items are very low in calories, typically only 10-20 calories per 50 grams.

Eating slowly and savoring your food will allow more time for nutrients to be digested and absorbed and the satiety signals to kick in, meaning that you may eat smaller portions or no longer want a dessert after your main meal.

Begin your main meal by eating the high-protein and the bulky low energy density food items on your plate first because you may start to feel full before you start consuming the higher energy food items containing carbohydrate and/or fat.

Try to stop eating when you feel 80% rather than 100% full.

Avoid drinking sugar-sweetened beverages; choose the low energy versions with artificial sweeteners and no added sugar.

Use only skimmed or semi-skimmed milk (or soya milk) and reduced fat versions of yogurt, coleslaw etc.

Avoid drinking alcoholic beverages. If you don’t want to cut out alcohol altogether, then compensate by doing more exercise: one small (125 mL) glass of wine or a half pint (235 mL) of beer both contain about 100 kcal and you will have to walk or jog one mile (1.6 km) to burn that off.

A multivitamin and mineral supplement supplying no more than the RDA may be useful during periods of energy restriction to guard against possible deficiencies. This is the only supplement you will need apart from a vitamin D3 supplement (1,000 IU or 25 micrograms per day) in the winter months.

Remember that to lose weight dieting is not the only answer. Increase your energy expenditure by doing more exercise (see the next chapter for further details). It will improve your fitness and health and help to maintain your muscle mass when you are in negative energy balance.

Measure body weight weekly and obtain measurements of body fat regularly (every 1-2 months). Keep a record of the changes.

Blog #3: Exercise For Weight Loss: What Sort Of Exercise Is Best For Burning Fat?

The following is an adapted excerpt from my new healthy lifestyle guidebook “Eat, Move, Sleep, Repeat” which is being published by Meyer & Meyer. The book will be released in January 2020 and you can order your copy from Amazon now via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_1?crid=1R3EQI16R1CCN&keywords=eat+move+sleep+repeat&qid=1561723790&s=gateway&sprefix=eat+move+%2Caps%2C139&sr=8-1

Many people think that to lose weight they have to go on a diet but doing more exercise is an alternative way to lose body weight by creating a negative energy balance. In obese people (BMI of 30 kg/m² or more), the effectiveness of exercise programs to achieve weight loss has been questioned because of problems related to a lack of motivation to do physical activity, non-compliance with exercise programs lasting more than a few weeks, and impaired ability (e.g., poor fitness, flexibility or stamina) to perform some forms of exercise, particularly weight-bearing activities like jogging. In moderately overweight people (BMI of 25-29 kg/m²) with a real desire to lose weight, these factors are less likely to be a problem. Most people can include exercise sessions with the specific aim of increasing energy expenditure, and they can exercise at an intensity high enough or for a duration long enough to cause a significant increase in the amount of energy expended. Working people may have difficulty finding time to exercise, so for them higher intensity with relatively short duration would be the exercise of choice, at least on working days. For those lucky enough to have time on their hands such as retired folk like myself, long walks (e.g., 5 miles or 8 km taking about two hours) are a great way to exercise while enjoying the local scenery and still being able to engage in conversation. Doing a 5-mile walk will burn about 500 kcal for most people. Do that seven days a week and you will lose about one pound of body fat without affecting your appetite or having to eat less.

Generally, adding exercise to a weight loss program results in weight loss that is fat loss (rather than lean tissue loss), and a combination of dieting and exercise is the most effective way to lower body weight and to maintain it at a lower level after weight reduction; it is nearly always more successful for weight loss than dieting or exercise alone. The exercise, especially if it includes some resistance exercise and is followed by a high-protein post workout meal, will also help to maintain muscle mass and resting metabolic rate. Some forms of exercise can also increase the resting metabolic rate for several hours after exercise although this is not a significant factor in weight loss, despite some claims to the contrary by so-called fitness experts.

Taken as a whole, the evidence suggests that for maximum fat burning during exercise itself, you should exercise aerobically at an intensity close to that which elicits your maximal fat oxidation rate. Depending on your fitness, this will be around 55-65% of your aerobic capacity (or 60-80% of your maximum heart rate which can be estimated as 220 minus your age in years). As for the duration and frequency of exercise sessions, the most important factor is your total energy expenditure over any given time period. So, for example, six dynamic exercise (e.g., cycling or running) training sessions per week of one-hour duration at 75% of your maximal heart rate would be equivalent to three sessions of two hours duration at the same relative exercise intensity. The goal is to increase your total volume of exercise (within reasonable limits), so that you will burn more fat. Fewer but longer sessions may be more advantageous as fat oxidation becomes an increasingly important fuel as the duration of exercise increases. An additional benefit of structuring sessions this way is that it allows longer periods of recovery in between each bout of exercise and some of that recovery time could be used to do high intensity interval exercise sessions which should increase your aerobic capacity, further increasing your muscles’ ability to burn fat. If you are undecided about whether to run or cycle, it is worth knowing that rates of fat oxidation have been shown to be slightly higher for a given rate of oxygen uptake during running compared with cycling.

Furthermore, any fat loss program should ideally include some resistance training because this increases muscle mass and lean body mass, which is desirable as lean tissue is metabolically far more active than adipose tissue. Increasing your muscle mass by including some resistance training means that your resting metabolic rate can be increased to a small degree, helping you to achieve your negative energy balance more easily. If you are combining both dieting and exercise to lose weight (or just dieting) the addition of resistance exercise sessions will help to maintain your resting metabolic rate which will otherwise fall by about 10-15% as your body adapts to your lower food energy intake. Two or three short (~15-20-minute) sessions of resistance training per week comprising of 8-12 exercises designed to work all the major muscle groups (one to two sets of 10-15 repetitions per exercise with enough weight set so that the repetitions can only just be completed) should produce good results in those who are not experienced resistance trainers.

Blog #4: What Is A Low Energy Density Diet And Why Is It Good For Weight Loss?

The following is an adapted excerpt from my new healthy lifestyle guidebook “Eat, Move, Sleep, Repeat” which is being published by Meyer & Meyer. The book will be available later this year and you can pre-order your copy from Amazon now via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_1?crid=1R3EQI16R1CCN&keywords=eat+move+sleep+repeat&qid=1561723790&s=gateway&sprefix=eat+move+%2Caps%2C139&sr=8-1

The low energy density diet provides a total of 1,300 to 1,500 kcal/day with an energy density of less than 1.5 kcal/g. The diet typically contains 25-30% protein with low-fat (less than 30 g/day) and limited carbohydrate (less than 130 g /day). The main principle of a low energy density diet is to avoid fatty foods (or use reduced fat versions of foods like cheese and milk), use only lean meat (trim off any visible fat and remove skin from poultry), and fish, and include lots of fruit and non-starchy vegetables such as spinach, broccoli, cauliflower, green beans, or salad leaves with tomatoes, onion, celery, etc. Gourds (a fleshy, typically large fruit with a hard skin) including eggplant (aubergine), squash, marrow, melon, and zucchini (courgette) are a particularly good choice, as all have an energy density less than 0.5 kcal/g. In fact, most vegetables have an energy density less than 1.0 kcal/g (e.g., salad leaves and spinach are only 0.2 kcal/g, carrots are 0.4 kcal/g, and beans are about 0.9 kcal/g). Using the principles of energy density, it is possible to achieve a lower calorie intake which will help towards weight loss, whilst allowing generous, voluminous portions of food and get an overall balanced diet that is high in protein, fiber, micronutrients, and phytonutrients. Because you can eat large volumes of food on this diet and it is high in protein you avoid the hunger pangs that are many a diet’s downfall. For these reasons, a low energy density diet with high-protein is an excellent choice for safe and effective weight loss.

Blog #5: Intermittent Fasting Diets

The following is an adapted excerpt from my new comprehensive evidence-based healthy lifestyle guidebook “Eat, Move, Sleep, Repeat” which is being published by Meyer & Meyer Sport. The book describes the pros and cons of many weight loss diets and this article describes my thoughts on the currently popular intermittent fasting diets. My book will be available later this year and you can pre-order your copy from Amazon now via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_1?crid=1R3EQI16R1CCN&keywords=eat+move+sleep+repeat&qid=1561723790&s=gateway&sprefix=eat+move+%2Caps%2C139&sr=8-1

Intermittent fasting diets (IFD), of which there are several, have become popular in recent years, in part because of a lot of media coverage and backing from television and film celebrities. However, there is reasonable evidence that they can be effective, as all of them will reduce weekly energy intake to some degree. They may not be quite as beneficial for women as men and may also be a poor choice for people who are prone to eating disorders. It is also important to bear in mind that you should aim to eat healthily as well (see chapter 4 of Eat, Move, Sleep, Repeat for further details) during the normal eating phase of the diets.

The alternate-day fasting diet means fasting every other day. This can be a complete fast, or some versions of this diet allow you to consume up to 500 kcal on the fasting days. A full fast every other day seems rather extreme and could lead to insufficient protein intake with negative consequences for muscle mass, so it is not recommended for athletes and other highly physically active people. The version where you eat normally on four days of the week and consume only about 500 kcal on alternate days is sometimes referred to as the 4:3 diet. A less extreme version of this IFD diet is the 5:2 diet (also commonly known as the “Fast Diet”), popularized by the British television medic Dr Michael Mosley, which involves eating normally on five days of the week, while restricting intake to 500 kcal (for women) or 600 kcal (for men) on two days of the week (usually these are separated by two to three days such as fasting on Mondays and Thursdays). On the fasting days (note this is not strictly fasting, rather just eating much less than normal on two days of the week), you could eat two small meals (250 kcal per meal for women, and 300 kcal for men). These should be high-protein meals for better satiety (as mentioned in chapter 6) and to maintain muscle mass. Even so, the very low energy intake on the semi-fasting days of the 5:2 and 4:3 intermittent fasting diets will almost certainly not provide sufficient protein and micronutrients to meet minimum daily requirements. This can be compensated for by having a high-protein dinner on the day before the semi-fasting day and a high-protein breakfast on the day after. A slightly less drastic version of these two IFDs with a lower risk of consuming inadequate amounts of protein is to allow up to 800 kcal on the fasting days. Dr Mosley has more recently promoted a modified version of the 5:2 diet in which he recommends a healthy Mediterranean diet (see chapter 4 for details) on the non-fasting days. This is a very sensible recommendation in my opinion, especially if it incorporates some high-protein and low energy density meals on the non-fasting days (see later in this chapter for the reasons why). Alternatively, for a change of foods and flavours, you could try adopting the Japanese diet on the non-fasting days.

Another IFD involves fasting from evening dinner one day to dinner the next (i.e., skipping both breakfast and lunch for a day), amounting to a 24-hour fast, and doing this on two days of the week. You should eat a normal meal at dinner on these days and not compensate for your hunger by eating more than usual; eating slowly and having a high-protein meal will again help with satiety. Another simple IFD is to skip one meal (usually lunch) during the day.

The Warrior Diet was popularized by ex-army fitness expert Ori Hofmekler and involves eating small amounts of raw fruits and vegetables during the day, then eating one large meal in the evening. The diet also emphasizes food choices (whole, unprocessed foods) that are quite similar to a Paleo diet (described later in this chapter) in which you are encouraged to eat anything we could hunt or gather way back in the Paleolithic era (also known as the Stone Age), including foods like meats, fish, nuts, leafy greens, regional vegetables, and seeds but avoiding processed foods, ready meals, pasta, bread, cereal and candy.

Another type of IFD is what is known as time-restricted feeding. This is a daily eating pattern in which all your food is eaten within an 8-12-hour timeframe every day, with no deliberate attempt to alter nutrient quality or quantity. This usually involves abstaining from breakfast, thus extending the duration of your normal overnight fast (the time when you are asleep and not eating), which gives your body more time to burn fat and do essential repairs. Outside of this time-restricted eating period, a person consumes no food items apart from drinking water or low-calorie beverages to stay well hydrated. Such beverages could also include black unsweetened coffee or green tea (without milk). Time-restricted eating is a type of intermittent fasting because it involves skipping breakfast or both breakfast and lunch. It is a pattern of eating that probably is similar to what our ancient ancestors adopted: most of the daytime would be spent hunting and gathering food, and most of the eating would take place after dark.

Although time-restricted eating will not work for everyone, some may find it beneficial. Some recent studies have shown that it can aid weight loss, improve sleep quality, and may lower the risk of metabolic diseases, such as type 2 diabetes. Modern humans, due to societal pressures, work schedules, and with the availability of night-time indoor illumination and entertainment, stay awake longer, which enables food consumption for longer durations of time. This extended duration itself, in addition to the caloric surplus, can be detrimental to health by reducing sleep time. A recent study using a smartphone app to monitor eating time has revealed more than 50% of adults spread their daily food and beverage intake over 15 hours or longer. Such extended eating of high fat or high or high glycemic index diets is known to predispose laboratory animals to metabolic diseases.

It is probably best to start a time-restricted eating plan gradually. Try starting with a shorter fasting period and then gradually increasing it over time. For example, start with a fasting period of 10:00 pm to 6:30 am. Then increase this by one hour every two days to reach the desired fasting period (usually around 8:00 pm to 1:00 pm the next day – leaving a time-restricted eating period of seven hours). Studies have suggested that restricting feeding periods to less than six hours is unlikely to offer additional advantages over more extended feeding periods.

The largest evidence base for the efficacy of IFDs derives from studies that have used some of the more extreme forms, such as alternate day fasting, which, according to several studies, can lead to significant body weight loss amounting to 3-8% over a period of 3-24 weeks. With alternate-day fasting the rate of weight loss averages about 0.7 kg/week (1.5 lbs/week); with other IFDs the rate of weight loss is less at about 0.25 kg/week (0.5 lbs/week). Studies comparing intermittent fasting and continuous calorie restriction show no difference in weight loss if calories are matched between groups.

The IFD With Variety (illustrated in the Figure accompanying this article) is a unique plan that is my own invention and I believe it will suit many people. You consume only 800 kcal on two days of the week (Monday and Thursday). These IFD days are preceded by a high protein diet day supplying 1600 kcal on Sunday and Wednesday. On Tuesday and Friday you consume 2000 kcal which is enough to most people’s resting daily energy requirement but you eat diets that are known to be very healthy, namely the Mediterranean and Japanese diets, respectively. Finally on Saturday you eat the Flexitarian diet which is another healthy diet that is primarily plant-based, of low energy density and voluminous but allows you a choice of a small portion (up to 6 ounces) of lean meat, poultry or fish and comes in at 1700 kcal. In total this seven-day IFD With Variety generates a 3500 kcal energy deficit which should result in a loss of 1 lb of body fat tissue. Keep it up for 10 weeks and you will have lost over 10 lbs in weight. The big advantage of including multiple diets in your weekly meal plan is that you will not get fed up (pardon the pun!) with dieting, you will not get food cravings, you will get all the essential nutrients you need as well as plenty of those non-essential but health promoting nutrients fibre and phytochemicals. All this means that you will be eating healthily with lots of variety and will be much more likely to stick to your weight loss plan. Full details of all the diets described in this article, together with many example meal plans, plus how to combine dieting with exercise to optimize body fat and weight loss can be found in my new book Eat, Move, Sleep, Repeat available to order now from Amazon via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_4?qid=1565424538&refinements=p_27%3AMichael+Gleeson&s=books&sr=1-4

Blog #6: Effects Of Exercise On Immune Function And Risk Of Infections

We all suffer from colds at some time but recent research indicates that a person’s level of physical activity influences their risk of respiratory tract infections such as a cold, most likely by affecting immune function. Moderate levels of regular exercise seem to reduce our susceptibility to illness compared with an inactive lifestyle but long hard bouts of exercise and periods of intensified training put athletes at increased risk of colds and flu.

Upper respiratory tract infections (URTIs) are the most common ones that people get and include the common cold, sinusitis and tonsillitis. Most are due to an infection with a virus. The average adult has two to four URTIs each year and young children have twice as many. We are constantly exposed to the viruses that cause these infections, but some people seem more susceptible to catching URTIs than others. Every day our immune system protects us from an army of pathogenic microbes that bombard the body. Immune function is influenced by an individual’s genetic make-up as well other external factors such as stress, poor nutrition, lack of sleep, the normal ageing process, lack of exercise or overtraining. These factors can suppress the immune system, making a person more vulnerable to infection.

Exercise can have both a positive and negative effect on the functioning of the immune system and can influence a person’s vulnerability to infection. Researchers have found a link between moderate regular exercise and reduced frequency of URTIs compared with an inactive state and also with excessive amounts of exercise and an increased risk of URTIs. A one year study by Dr David Nieman and colleagues of over 500 US adults found that participating in 1-2 hours of moderate exercise per day was associated with a one third reduction in the risk of getting a URTI compared with individuals that had an inactive lifestyle. Other studies have shown that people who exercise 2 or more days a week have half as many days off school or work due to colds or flu as those who don’t exercise.

However, more is not always better in terms of exercise volume as other studies have reported a 2 to 6 fold increase in risk in developing an URTI in the weeks following marathon (42.2 km) and ultra-marathon (90 km) races. This is due, in part, to increased levels of stress hormones like adrenaline and cortisol that suppress white blood cell functions. After strenuous exercise, athletes enter a brief period of time in which they experience weakened immune resistance and are more susceptible to viral and bacterial infections, in particular URTIs. Post-exercise immune function depression is most pronounced when the exercise is continuous, prolonged (>90 minutes), of moderate to high intensity (55-75% of aerobic capacity), and performed without food intake. Another problem for athletes is that their exposure to pathogenic (disease causing) microorganisms in the environment may be higher than normal due to increased rate and depth of breathing during exercise (increasing exposure of the lungs to airborne pathogens), exposure to large crowds and frequent foreign travel. Some of the reported sore throats may not be due to infectious agents but to non-infectious airway inflammation caused by allergies or inhalation of pollutants and cold dry air.

A common perception is that exposure to cold wet weather can increase the likelihood of catching the common cold but the available evidence does not support this. Most people are more susceptible to colds in winter (which is possibly due to reduced vitamin D status at this time) but numerous studies on athletes indicate that they tend to be most susceptible to picking up infections at times close to competition. This usually follows a period of intensive training and added mental stress with the anxiety of wanting to perform well. The worry for athletes is that even a mild infection can impair their ability to perform at the highest level. Preventing infections is therefore very important to them and they can help themselves by ensuring good personal hygiene, good nutrition and minimizing other life stresses.

These illness prevention strategies are explained in Blog #7.

Blog #7: Reducing Your Risk Of Picking Up Common Infections

A concern for many people throughout life is to avoid picking up infections at home, in the workplace, in the city, in educational, social and leisure facilities and when we are on vacation. The most common infections are the common cold, influenza, tonsillitis, measles, ear and eye infections and tummy bugs. Our immune system protects us against the viruses and bacteria that cause these infections, but because there is a genetic influence on the efficacy of our immune systems, some people are more prone to infections than others. However, just as with the risk of chronic diseases like type 2 diabetes and coronary heart disease, our susceptibility to common infectious diseases is also influenced by what we eat, how much exercise we do, and how well we sleep; our personal and food hygiene practices are also important. A consequence of this is that there are various nutritional, behavioral, and lifestyle strategies that we can easily implement to help minimize our risk of infections. These are fully explained in my new healthy lifestyle guidebook “Eat, Move, Sleep, Repeat” which will be published by Meyer and Meyer Sport in January 2020. As illustrated in the accompanying diagram there are several things we can do to reduce our risk of picking up infections: (1) Avoid contact with the pathogenic micro-organisms that cause infections and (2) Make our immune systems stronger and more robust. You can pre-order your copy of Eat, Move, Sleep, Repeat from Amazon now via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_1?crid=1R3EQI16R1CCN&keywords=eat+move+sleep+repeat&qid=1561723790&s=gateway&sprefix=eat+move+%2Caps%2C139&sr=8-1

Blog #8: Are The Claims About Superfoods For Real?

The following blog about so-called “superfoods” is an adapted excerpt from my new healthy lifestyle guidebook “Eat, Move, Sleep, Repeat” which is being published by Meyer & Meyer. The book will be available for delivery in January 2020 and you can pre-order your copy from Amazon now via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_1?crid=1R3EQI16R1CCN&keywords=eat+move+sleep+repeat&qid=1561723790&s=gateway&sprefix=eat+move+%2Caps%2C139&sr=8-1

The term “superfood” is actually a marketing term for food with supposed health benefits as a means to sell more products. Scientists do not use the term, and nutritionally speaking, there is no such thing as a superfood. No single food item holds the key to good health or prevention of disease although it is true to say that certain food groups can contribute to some health benefits when eaten as part of a healthy balanced diet. Such foods include dark leafy green vegetables that are rich in fiber and phytonutrients, berries that have a high content of antioxidants, eggs that are rich in vitamins, protein and some unique antioxidants (e.g., lutein and zeaxanthin, which are known to protect vision and eye health), oily fish like salmon and mackerel that have a relatively high content of vitamin D and omega-3 fatty acids which have anti-inflammatory actions, herbs such as garlic, ginger, and turmeric which have some medicinal properties and vegetables that have a high nitrate content (e.g., beetroot and rhubarb) that are known help to lower blood pressure. The downside often is that you have to consume rather a lot of these foods to get the specific health benefits that are claimed. For example, to get 4 millimoles of nitrate (the effective dose to lower blood pressure by 5-10 mm Hg), you would need to consume about 200 g of beetroot which is rather a lot. However, there are some products now available that supply beetroot as a juice (you need about 400 mL to get the effective dose) or better still as a shot of concentrated juice (you only need about 70 mL for the required dose). Others like turmeric and garlic can be taken in capsule form. However, the bottom line is that achieving optimal health through food and nutrition is more than about just focusing on one or two of the latest food trends.

Good health is best supported by eating a variety of nutritious foods every day. There are also some hidden dangers in labelling foods as superfoods. For example, people may assume that because they are super healthy, they can eat them in unlimited quantities, but they still contain calories, and you can gain weight from eating too much healthy food. It may also encourage people to eat one kind of food over another and can lead to certain good foods being excluded from the diet just because they do not appear on a superfood list. Although superfoods might be a good introduction to healthy eating, and while understanding the influence that food can have on your health can be interesting and enlightening, it is your overall diet that is the most important factor in determining how good your health can be. Alongside getting enough exercise and sleep, practicing good hygiene, and avoiding bad habits like smoking and binge drinking, that is.

Blog #9: What Are The Potential Benefits Of Taking Probiotic Supplements?

Probiotic-rich foods and supplements contain non-pathogenic bacteria that colonise the gut and can potentially yield a variety of health benefits that include reduced incidence of respiratory and gastrointestinal illness. There are several possible ways in which probiotics can act to produce these effects. By their growth and metabolism, probiotics help inhibit the growth of other bacteria, antigens, toxins and carcinogens in the gut, and reduce potentially harmful effects. Probiotics can also influence immune function via interaction with immune cells associated with the gut. Probiotics are found in several foods, particularly dairy products such as milk, yoghurt and cheese, although concentrations are relatively low. Consequently, there is widespread interest in use of probiotic supplements in both the general and sporting communities.

Probiotics have been used for over a century to manage common gastrointestinal conditions including stomach cramps, irregular bowel movements, excessive flatulence, diarrhoea, and irritable bowel syndrome. In research settings, the focus has been on verifying the clinical benefits of regular probiotic supplementation, and underlying mechanisms of action. Many studies have been conducted on the effects of probiotic use on gastrointestinal problems and upper respiratory tract infection (URTI) in the general population. A recent systematic review of 20 placebo-controlled trials in both children and adults concluded that probiotic use resulted in lower numbers of illness days, shorter illness episodes and fewer days of absence from school or work. Another recent review of probiotic benefits for URTI using data from randomised controlled trials involving 3,720 non-athletes from 12 studies concluded that probiotics were better than placebo in reducing URTI incidence by 47%, and the average duration of an acute URTI episode by 2 days.

The most important mechanisms of probiotic action are thought to be via influences on local immunity (by interaction with gut-associated lymphoid tissue and maintenance of gut barrier function) and systemic immunity (by enhancing some aspects of both innate and acquired immune responses). Certain probiotics, particularly those containing Lactobacillus or Bifidobacterium species, have been shown to enhance several aspects of immune cell functions including natural killer cell activity, the microbe killing capacity of neutrophils and monocytes, and increasing the levels of antibodies, with effects that can extend beyond the gut to other mucosal sites, including the respiratory tract.

Probiotics may be of particular benefit to athletes and people who are highly physically active. A recent comprehensive review identified 15 relevant experimental studies that investigated immunomodulatory and/or clinical outcomes of regular probiotic use in athletes. Of the 8 studies that recorded URTI incidence, 5 found reduced URTI frequency or fewer days of illness and 3 reported trivial or no effects. A randomised, placebo-controlled trial involving physically active individuals reported that 27% fewer URTI episodes were experienced in those who ingested daily a Bifidobacterium probiotic compared with placebo over a 150-day intervention period. The studies that have shown reduced URTI incidence in athletes have been mostly limited to Lactobacillus and Bifidobacterium species and used daily doses of ~10¹⁰ live bacteria. Although most studies have examined probiotic effects in relatively small numbers of recreationally active individuals over periods lasting less than 6 months, there is now sufficient understanding of the mechanism of action of certain probiotic strains, and enough evidence from trials with athletes and highly physically active peopleto signify that there are mostly positive effects.

Other potential benefits of probiotics could be reduced risk of gastrointestinal discomfort symptoms and diarrhoea (e.g. so-called runner’s trots) during prolonged exercise, reduced leakage of bacterial toxins from the gut into the blood (which the medics call endotoxaemia) during exercise in the heat, and reduced incidence of gastrointestinal infections – a particular concern when travelling abroad. Future research is likely to establish the long-term tolerance of probiotic supplementation in highly-trained athletes over several months to years, the possible benefits, if any, of cycling on and off probiotics, and the effectiveness of multi-component formulations combining several different probiotics species, or probotics and prebiotics (non-digestible food ingredients that promote the growth of beneficial microorganisms in the intestines).

Furthermore, the benefits of probiotics may extend beyond immunomodulation and reduction of illness risk according to new research that indicates the gut microbiota can communicate in a bidirectional manner with the brain and thus influence mood, stress responses and sleep quality. The basis of this is the recognition of the existence of a microbiota-gut-brain axis that can influence behaviour and cognition via the production of neurochemicals by commensal gut bacteria (we have about one kilogram of bacteria resident in our intestines) and probiotics. This system has probably evolved over the millennia during which animals have hosted bacteria in their gut for mutual benefit. The microbe-derived neurochemicals are the same as those produced by the host and there is some evidence from animal studies that these neurochemicals activate sensory nerve endings in the gut and information is then transmitted to the central nervous system via the vagus nerve. Microbes and their metabolism can also be influenced in turn by neurochemicals including hormones like adrenaline which is produced by the human body in response to stress. These interactions likely explain what we like to call our “gut feelings”!

The body’s stress response system reacts to various external stimuli that disrupt normal cellular function and metabolism to help return things back to normal. However, an excessive response to stress can trigger both mental and physical health problems. Studies in animals have shown that probiotics and gut microbiota reduce stress reactivity by modulating the neuroendocrine system and can have positive effects on behaviour and cognitive function (e.g. reduced anxiety, depression and defeatism) under stressful conditions. In humans, recent investigations of the effects of probiotics on both stress-related physical symptoms and stress biomarkers have shown beneficial effects. A series of double-blind, placebo controlled trials in medical students studying towards a nationwide academic examination were conducted by researchers in Japan. For 8 weeks before the exam, two groups of 70 students, consumed either Lactobacillus casei Shirota (Yakult) in a fermented milk drink or a placebo milk drink daily. The self-reported scores for abdominal dysfunction and cold-like symptoms and the number of genes with more than a 2-fold change in gene expression in white blood cells were significantly suppressed in the probiotic group compared with the placebo group during the study period. Levels of the stress hormone, cortisol, were also lower in the probiotic group close to the time of the exam. Thus, administration of the probiotic was shown to reduce stress-related physical symptoms and a hormonal biomarker of stress. Other recent studies indicate that regular daily ingestion of a Lactobacillus probiotic also improve sleep quality (earlier onset of sleep and longer sleep duration with probiotic compared with placebo) in medical students preparing for their academic exams..

These findings raise the possibility that probiotics could be of benefit for athletes recovering from intensive training and competition. Recovery involves both physical and psychological issues and a supplement that could reduce physical symptoms of stress and improve both mood and sleep quality would almost certainly be good for the athlete or games player. The importance of mental as well as physical recovery after intense competition is often underestimated, but a quote from someone who has a lot of experience of these issues, Dr Sam Erith, head of sport science at Manchester City FC, is illuminating: “the longer I do this job the more you see that mood and mind state are such powerful drivers for recovery”. Although further research is required to confirm these effects in the sporting population, it seems likely that probiotic supplements may provide multiple benefits for athletes and games players as well as the general public.

Blog #10 Physiological And Metabolic Demands Of Tennis

What makes a good tennis player?

Pretty obvious you might think: being tall helps, particularly with the serve and smash and for reaching balls hit to the sides of the court. However, success in most sports is determined by many factors including motivation, appropriate training, nutrition and tactics and tennis is no exception. Probably the most important factor is raw talent in terms of the body’s phenotype; in other words the body’s physical, physiological and metabolic characteristics. Certain physical characteristics are essential for success in many sports at the elite level. For example, in the past twenty years, no male tennis player under 1.75 m in height has won a Grand Slam event. To this list of physical attributes essential for success we could add motor skills such as hand-eye coordination which are extremely important in all racquet sports. Although these motor skills can be developed by a lifetime of practice, there is also probably a significant genetic component in terms of visual acuity and the ability to track a moving object as well as the ability to learn and execute complex movements such as the serve and topspin backhand.

Fitness, speed and agility

Good physical fitness is another important attribute for the top tennis player. Good aerobic fitness is required because games can last several hours. However, even top professional male players do not possess remarkably high maximal oxygen uptakes (VO₂max) – typically less than 60 ml/kg/minute - so this aspect of fitness appears less important than for soccer players, distance runners, cyclists and swimmers, where VO₂max values can be as high as 85 ml/kg/minute. Slow tennis players don’t win many singles matches, so agility and quickness on the court are important attributes. Bulging muscles are not so important (no one would describe Leighton Hewitt, the men’s 2001 champion as being a muscle-bound hulk) but a minimum level of strength is needed for success in both the men’s and women’s games. It is noticeable that most of the top women players (e.g. the Williams sisters, Capriati, Davenport, Klijsters) have quite well developed upper body strength compared to many of their less successful rivals and anyone who plays the game will realise that it is the combination of power and control that produces most winning serves and drives.

Activity patterns in tennis

Tennis play involves repetitive short bouts of high intensity exercise. Maintaining performance for the full duration of matches is obviously important to success and will depend to a large degree on the ability of muscle to recover from the last sprint effort. In tennis, players perform numerous very short sprints interspersed by variable periods of exercise of lower intensity (e.g. moving from side to side, jogging, walking) or rest. The cycles of activity and rest are largely unpredictable as they are imposed by the pattern of play and will vary greatly from player to player and from one match to another.

Most tennis matches (minimum of two sets) last at least 60 minutes and it is not uncommon for men’s matches to last for more than 3 hours, though 30-second breaks are taken at change of ends after every odd-numbered game. Compared with continuous exercise activities such as running and cycling, relatively little attention has been directed to the metabolic responses to games such as tennis, probably because of the lack of adequate experimental models to study these games in the laboratory. However, some standardised models of intermittent exercise have been developed in recent years that have gone some way to simulating the activity patterns observed in tennis and other sports such as squash, rugby and football.

In studies of singles tennis matches it has been noted that the ball is in play for around 25% of the time and the average duration of rallies is about 4 seconds on fast surfaces such as grass and carpet and about 10 seconds on slower clay and hard courts. During match play a player averages about 6 strokes per minute and covers an average distance of 13 metres per minute during rallies with a further 11 metres each minute covered by walking between rallies. Thus, for every hour of tennis play completed, each player covers about 1.5 km while performing numerous discrete bouts of action incorporating frequent changes of pace and direction as well as the execution of game skills such as serving, returning serve, volleying, driving etc.

Energy expenditure

Heart rates of top players have been recorded during friendly and competitive matches and typically have been found to be between 140 and 160 beats/minute for the majority of the playing time. Although measurement of oxygen uptake is likely to interfere with normal play, some measurements have been made with players wearing portable expired gas collection bags during casual games. These studies indicate that energy expenditure is typically about 44 kJ/minute (10 kcal/minute), and that the players were exercising at a relative intensity close to 50% VO₂max. Thus, for a typical singles match lasting 2 hours the average player will expend about 5000 kJ (1200 kcal). In doubles matches, energy expenditure is typically about two-thirds of that recorded for singles play. These values are likely to be underestimates of the true energy demands of competitive tennis, since the apparatus used to collect expired gas during play is likely to have hampered the activity of the players.

Fuel metabolism

Although tennis play is a predominantly aerobic activity, the intermittent nature of the exercise performed during a game means that players rely on anaerobic metabolism (meaning energy production without the use of oxygen) for brief bursts of sprinting. Jumping and explosive hitting actions also rely on anaerobic energy supply. However, blood lactic acid concentrations measured during the course of a game and at the end of a game in professional players are typically 3-4 mM. This is quite low compared with soccer and rugby (typically values of about of 5-6 mM are reported in these games). However, one would not expect to find high levels of lactic acid in the blood when the duration of each discrete bout of exercise averages less than 5 seconds, as it does in most tennis matches. In tennis, sprints are necessarily short. For this type of brief but very high intensity exercise, the muscle’s phosphocreatine store is used as the main energy source. Actually muscle can only use a compound called adenosine triphosphate (ATP) to directly fuel contraction. Phosphocreatine breakdown is used as a means to very rapidly resynthesise ATP. “Could creatine supplements be of benefit to tennis players?” I hear you ask. The answer is probably yes, because it appears that the main benefit of creatine supplementation is that it allows a faster rate of phosphocreatine resynthesis during the recovery period from the last sprint.

Fatigue

At high standards of competitive play it is noticeable that players suffer from fatigue during the final set and this is reflected as a drop in work rate (less distance covered and fewer sprints) and an increase in the incidence of unforced errors. It is common to see more missed shots in the later stages of games as players become tired and more mistakes are made. The development of fatigue during the game is likely to be related to depletion of the muscle glycogen stores (glycogen is a polymer form of the sugar glucose) and the development of dehydration and hyperthermia (especially in warm environmental conditions). Players who start matches with low glycogen stores in their leg muscles are likely to be close to complete glycogen depletion by the end of the second set and this has important implications for the training and nutritional preparation of players. Until relatively recently these issues have largely been ignored.

Many tennis matches last 2 hours or longer, and the nature of the game is such that the longer games are more close-fought affairs, often with longer rallies and where, ultimately, the difference between winning and losing is a few crucial points. Professional singles tennis matches in Grand Slam events have been known to last over 4 hours and even the ultra-fit top players including Michael Chang and Pat Rafter have been known to suffer cramp and heat exhaustion.

During prolonged continuous exercise the blood glucose concentration tends to fall, but this does not seem to be the case for intermittent high intensity exercise performed for 1-2 hours. In fact, blood glucose can rise slightly during this type of activity. The blood glucose concentration reflects the balance between the rate of glucose release from the liver and the rate of uptake of glucose from the blood by the muscles and brain. Blood glucose levels may start to fall if the match duration exceeds 3 hours. Hence, when long matches are anticipated, carbohydrate containing drinks should be consumed at regular intervals during breaks in play (e.g. at change of ends).

Food and fluid intake during a tennis match

I occasionally play for a local club team (Hinckley Town) in the men’s doubles Leicestershire league with a moderate degree of success. Matches are played in the evening and each pair plays three round robin matches (each of which is decided by the pair who is first to win 9 games). The total duration of play is about 3 hours. Some players don’t eat or drink anything during these matches, even though most will have come to play straight from work and won’t have eaten since lunchtime. This is a recipe for disaster (for them!). Even in the less demanding game of amateur men’s doubles play, players will lose at least 1.5 litres (and maybe as much as 3 litres) of fluid as sweat over the course of 3 hours and premature glycogen depletion is another potential problem. Hence, I strongly recommend that players take a drink bottle on court with them. Commercial sports drinks such as Lucozade Sport are suitable. These can be made to stretch a little further with little or no loss of efficacy by diluting them to two thirds of normal strength with water. It is, of course, a lot cheaper to make your own sports drink. The important ingredients are water, glucose (about 25 grams per 500 mL will suffice) and a pinch of table salt. Drinking a mouthful (about 80 mL) at each change of ends will help prevent dehydration and provide an additional source of energy. These factors might be crucial if victory is to be claimed in the last match.

Diet

Professional tennis players may be engaged in their sport either in training or competitions (singles and doubles) for up to 6 hours per day, 5-6 days per week. This level of activity is likely to result in muscle and liver glycogen depletion on a daily basis and for this reason a high carbohydrate diet must be consumed if performance is to be maintained. The dietary recommendations for top tennis players are therefore not very different to those given to athletes in other endurance sports. See my book Sport Nutrition 3rd edition, 2019 for details.

It's usually better to stand up when you hit the ball in tennis, but sometimes needs must!

Blog #11: Coffee Makes Exercise Feel Easier

When it comes to exercise and sport, coffee consumption gives us the motivation to ‘go for it’, helping us to exercise harder and longer. As well as enabling you to perform for 30% longer, caffeine, which naturally occurs in coffee, improves alertness and the ability to sustain motor skills to make exercise feel easier, positively impacting our persistence, vigour and output levels. One mug of coffee consumed one hour prior to exercise has been shown to improve endurance and performance in cycling, high intensity running, repeated sprinting and sports such as football and rugby.

Some athletes consume caffeine to enhance their endurance, alertness and motor skills. These benefits result from the actions of caffeine in the brain where it reduces the chemical messages that normally induce fatigue and stimulates energy production and fat oxidation.

Studies show that if you consume enough caffeine at the right time, it can enhance your physical performance. Research studies have shown that black instant coffee consumed one hour prior to exercise can improve endurance performance in a similar way to pure caffeine (of equivalent amounts), which suggests coffee may be a very effective way to consume caffeine before exercise. Studies have also found that caffeine consumption has a greater effect on physical performance in those who are recreationally active than in trained athletes, and can improve cycling, running and high-intensity sports such as football and rugby over a 80-90 minute period.

Coffee is a popular drink in the UK with around 70 million cups consumed every day. The overwhelming weight of scientific information suggests that moderate coffee consumption of four to five cups per day (400 mg of caffeine) can contribute to a healthy, balanced diet and may confer some health benefits. Contrary to popular belief, coffee is also an important source of fluid in the diet and exercise lovers who drink it do not need to compensate by increasing their intake of water.

This will come as welcome news to people that have taken up some form of exercise or sport in recent years and those buoyed by the year of sports we will enjoy in 2020, including the Tokyo Olympic Games.

Here are my insights on coffee consumption to make your exercise feel easier:

Drink a cup of strong coffee one hour before a morning or lunchtime exercise session. Use an artificial sweetener rather than sugar if you are exercising to lose weight. If you want to exercise in the afternoon or evening, enjoy a coffee with your lunch to avoid the effect of the lunchtime dip.

For competitive sports, consuming coffee improves attention to detail, observance of your surroundings, and reduces symptoms of fatigue through caffeine’s effect on the central nervous system.

Hydration is important for endurance exercise performance. Coffee, when consumed in moderation (four to five cups of coffee or 400 mg of caffeine per day), provides similar hydrating qualities to water and does not cause dehydration.

For pregnant women the NHS recommends consuming no more than 200 mg of caffeine per day from all sources (an average mug of instant coffee contains approximately 100 mg of caffeine).

Blog #12: Why Type 2 Diabetes Is The Major Disease Of The 21st Century

Type 2 diabetes mellitus, also known as non-insulin-dependent diabetes mellitus, usually comes on slowly, is relatively rare below the age of 40, and most often develops in people who are overweight and sedentary. The main problem in type 2 diabetes is that the body tissues (e.g., adipose tissue, liver, and skeletal muscle) become resistant to the action of insulin which normally stimulates these tissues to take up blood-borne glucose when the blood glucose level is elevated such as after a meal. The lack of tissue response to insulin – often referred to as insulin resistance – results in sustained hyperglycemia (higher than normal blood glucose concentration) with many serious complications including cardiovascular and kidney diseases, increased incidence of infections and ulcers, limb amputation, blindness and reduced life expectancy if it is not properly managed.

Type 2 diabetes has exhibited increasing prevalence in the adult population since the late 1950s. In 1960 the percentage of the US population with diagnosed diabetes was close to 1.0%, by 1990 it had risen to 2.7%, in 2000 it was 4.7%, and in 2018 it stands at 9.0% (figure 1.2). It is projected to rise to close to 12% by 2030, and this does not include people (estimated to be approximately 3% of the population) who may have type 2 diabetes but have not yet had a confirmed diagnosis. Alarmingly, about 34% of the US population in 2018 were been confirmed to have prediabetes, a condition that if not treated often leads to Type 2 diabetes within 5 years. So it is rapidly becoming the disease to beat in the 21st century.

In the past we have beaten other diseases. Before the 19^th century the major diseases were infections caused by viruses (e.g., measles, mumps, polio, smallpox) or bacteria (e.g., bubonic plague, tuberculosis, typhoid, whooping cough). The introduction of vaccines in the 19^th century and antibiotics in the 1940s has resulted in these diseases being eliminated or greatly reduced in incidence. Improved nutrition, better medications, and improved sanitation and hygiene practices have also contributed to the much lower prevalence of infectious diseases that we now take for granted. Lung cancer became a big problem in the 20^th century due to the smoking of tobacco products and increasing air pollution, but in recent years the incidence of lung cancer has dropped as many people have quit smoking or switched to less harmful vaping. In the early 1980s we had the start of the Acquired Immunodeficiency Syndrome (AIDS) epidemic caused by the Human Immunodeficiency virus (HIV) which attacks and destroys crucial white blood cells (called CD4+ T-helper lymphocytes) and is transmitted through sexual contact or blood. These cells direct the body’s immune responses to other viral and bacterial infections. The loss of these T cells leads to the point where opportunistic infections can become fatal although nowadays, while there is still no cure for HIV, there are very effective treatments that enable most people with the virus to live a long and healthy life.

Becoming much more prevalent now are other forms of what we could call “self-inflicted disease”, namely obesity, type 2 diabetes and hypertension and the health complications that result from them including increasing fatality from cardiovascular disease and cancers. For these diseases of modern society that affect increasing numbers of people in developed countries, medication will almost certainly not be the answer. Although there may be some improvements to drug treatment to help the management of type 2 diabetes, it is very unlikely that a drug will be found to cure the condition. Changes to diet and lifestyle are the things that are needed. Simply put, weight loss is the key to curing type 2 diabetes, and avoiding excessive weight gain in the first place is the key to its prevention. This will require government investment in health and nutrition education, the introduction of taxes on high calorie and high sugar food products to discourage people from buying them, and healthcare programs to help people get rid of type 2 diabetes by dieting and/or doing more exercise. Most importantly, it needs people to take these messages on board and make a conscious decision to change their unhealthy lifestyle.

Current projections of the incidence of type 2 diabetes suggest that the numbers of people with the condition and those that die prematurely from it (we’re talking about living 5-10 years less than average here) will increase considerably more in the next 10-30 years unless something is done about it very soon. The good news for people with type 2 diabetes, and especially those who have only recently been diagnosed with the condition, is that you can get rid of it through your own actions. In my new book Beating Type 2 Diabetes (published by Meyer and Meyer Sport in April 2020) I explain how.

Beating Type 2 Diabetes is available to pre-order now from Amazon UK via this weblink: https://www.amazon.co.uk/Beating-Type-Diabetes-Adjusting-Lifestyle/dp/1782551999/ref=sr_1_16?crid=502SE5YHQK4C&keywords=michael+gleeson&qid=1574069097&s=books&sprefix=michael+glees%2Cstripbooks%2C141&sr=1-16

Or from Amazon USA via this weblink: https://www.amazon.com/s?k=beating+type+2+diabetes+by+michael+gleeson&i=stripbooks-intl-ship&ref=nb_sb_noss

Blog #13: Eating A Diet For Optimal Health Does Not Have To Be Complicated: Follow My Food Pyramid

Too often we see advice from so-called diet experts telling us that we need to eat diets that have certain food group or macronutrient restrictions if we want to be healthy. I do not subscribe to that view. Here is my Food Pyramid For Optimal Health. Follow these principles for a healthy well-balanced diet that contains optimal amounts of high quality protein, low energy density fruits and vegetables providing plenty of health-promoting fiber and phytonutrients and will give you all the essential nutrients you need. All this without eliminating any particular macronutrients or food groups. This diet can help prevent obesity and chronic disease and put you on the road to optimal health. Now add in some regular non-exhausting moderate aerobic and resistance exercise and follow guidelines for getting good sleep quality and hygiene. Read more on this in my new healthy lifestyle guidebook book Eat, Move, Sleep, Repeat which provides comprehensive, evidence-based advice on how to attain optimal health and safe, effective diets for weight loss. Order your eBook or Paperback copy from Amazon now via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_1?crid=1R3EQI16R1CCN&keywords=eat+move+sleep+repeat&qid=1561723790&s=gateway&sprefix=eat+move+%2Caps%2C139&sr=8-1

Blog #14: How Much Protein Should People Eat?

People often get confused about the need or protein in the diet and in particular the amount they should eat and where they can get their protein from apart from red meat. People are also often unsure what the concept of protein quality means to them. The purpose of this blog is to explain why protein in the diet is essential and how much we need to achieve optimal health.

Proteins provide structure to all cells in the human body. They are an integral part of the cell membrane, the cytoplasm, and the organelles. Muscle, skin, and hair are composed largely of protein. Bones and teeth are composed of minerals embedded in a protein framework. When a diet is deficient in protein, these structures break down, resulting in reduced muscle mass, loss of skin elasticity, and thinning hair. Many proteins are enzymes that increase the rate of metabolic reactions. Protein contains 5 kcal of energy per gram but only 4 kcal per gram is available to use in the body and it is not normally used as an energy source except when carbohydrate (glycogen) stores become depleted and during periods of starvation. The building blocks of proteins are amino acids and most proteins contain 20 different amino acids. Nine of the amino acids cannot be synthesized in the body and so must be obtained from the diet. Hence, they are called the essential amino acids.

The recommended daily protein intake is usually a minimum of 0.8 g protein per kg of body weight (so about 56 g or 2 oz for a person weighing 70 kg). Protein intake in the Western world is usually well in excess of the recommendations, averaging about 80 to 100 g/day with protein providing 10% to 15% of the total daily energy intake. Because meat, poultry, and fish are the most common sources of protein, vegetarians and vegans could be at risk for marginal protein intake. Vegetarians often compensate by eating more grains and legumes, which are excellent protein sources. But grains and legumes do not contain all nine essential amino acids. Grains (e.g., wheat, rice, oats, cornmeal, barley) lack the essential amino acid lysine, and legumes (e.g., peas, beans, chickpeas, lentils) lack methionine. An exception may be well-processed soybean protein, which is a high-quality protein comparable to protein from animal sources. For vegetarians who might lack certain essential amino acids in their diet, the problem can be solved by not eating grains and legumes in isolation but combining both grains and legumes in their meals (together with other protein sources such as cheese or egg). Some people prefer to follow a semi-vegetarian diet — also called a flexitarian diet — which is primarily a plant-based diet but includes meat, dairy, eggs, poultry, and fish on occasion or in small quantities. This option can be a very healthy diet.

Both the amount and the quality of protein are important. Proteins that contain all the essential amino acids are called complete proteins or high-quality proteins. Proteins that are deficient in one or more amino acids are called incomplete proteins, and they are commonly referred to as low-quality proteins. Incomplete proteins are unable to support human life and growth. Animal proteins are generally of higher quality than plant proteins, although the individual amino acids found in animal proteins and plant proteins are identical and of equal quality. The quality of the protein therefore depends purely on the kinds of amino acids present in the protein. Animal protein is considered of higher quality not only because all essential amino acids are present but also because they are present in larger quantities and in proper proportion.

All nine essential amino acids must be obtained by dietary intake. Even a short supply of any essential amino acid can interfere with normal protein synthesis in the body. An appropriate selection of plant protein sources can provide an adequate supply of amino acids, but consumption of animal protein is more likely to ensure a balanced intake. By combining plant foods such as rice and beans, obtaining a balanced intake of amino acids is possible. Essential amino acids that are deficient in one food can be obtained from another, so that in the overall diet, all amino acids are obtained. Proteins from sources that balance the amino acid intake are called complementary proteins.

In the developed world, where protein deficiency is uncommon, dietary protein intake is less critical and not related to disease. But in developing countries, protein deficiency is more common and can result in kwashiorkor (a pure protein deficiency, mainly in children, characterized by a bloated belly caused by edema as well as impaired immunity with increased susceptibility to infections) or marasmus (a protein deficiency resulting from a total dietary energy deficiency, characterized by extreme muscle wasting). Extreme protein deficiency is ultimately fatal due to vital organ breakdown or infection, and it is a sad reflection of today’s society and global politics that such problems in poorly developed countries are still tolerated or ignored. This is my personal view, but I am sure it is shared by many others.

Although it has sometimes been suggested that long-term consumption of a high-protein diet may result in impaired kidney function, evidence for this is nonexistent. A meta-analysis by scientists at McMaster University in 2018 has confirmed that there is no need for concern on this issue. The researchers examined 28 studies involving over 1,300 participants that had investigated the effects of high protein diets on glomerular filtration rate, an index of kidney function which generally falls when kidneys become damaged or diseased. The studies included in their meta-analysis included participants who were healthy, obese, or had type 2 diabetes and/or high blood pressure and the high protein diets contained 1.5 g of protein per kilogram of body weight per day, at least 20% of total caloric intake coming from protein or at least 100 g of protein per day. They found that there is simply no evidence linking a high protein diet to kidney disease in healthy individuals or those who are at risk of kidney disease due to conditions such as obesity, hypertension or even type 2 diabetes. For people suffering from preexisting kidney problems, this circumstance may be different and an upper limit to protein intake of 1.6 g per kilogram body weight per day may be advised. In normal health, most of the excess amino acids are broken down, and the resulting (toxic) ammonia nitrogen is excreted mainly as urea by the kidneys, and there is no risk to health, at least with intakes up to about 2.5 g per kilogram body weight per day which are sometimes reached by bodybuilders. Another health concern related to a high dietary protein intake is that consuming large amounts of red meat and processed meat has been shown to increase the risk of colorectal cancer.

Evidence derived from numerous large scale prospective epidemiological studies and their meta-analyses shows that red meat (beef, lamb, and pork) and processed meat (including bacon, ham, and salami) increases colorectal cancer risk by 20-30%. According to current dietary guidelines, the recommended amount of red meat for healthy people is 500 g/week or 70 g/day. It is also recommended to limit intake of processed meat. In contrast, white meat (fish and poultry) is thought to be safe to eat and is not associated with colorectal cancer risk. A likely cause of the carcinogenic effects of red and processed meat is the presence of heterocyclic amines which are produced when meat is cooked at high temperature. Processed meat also contains other carcinogens called nitrosoamines and nitrosoamides. The formation of heterocyclic amines can be diminished by not exposing meat surfaces to flames and using aluminum foil to wrap meat before oven roasting. To reduce the carcinogenic effects of heterocyclic amines, the diet should be high in dietary fiber sources such as wholegrain foods and vegetables. Red meat can be made safer to eat by trimming any visible fat before cooking. These health concerns about red meat do not mean we should all become vegetarians. Meat is an important source of nutrients including essential amino acids, iron, zinc, and vitamin B12. The take home message is that meat should be consumed in moderation and balanced with other foods, particularly high fiber vegetables.

Research on body builders and the elderly indicates that in order to achieve optimal rates of protein synthesis after a meal in order to gain muscle mass in response to resistance training or to prevent muscle loss with aging (which the medics call sarcopenia) we should be eating protein more regularly in our meals throughout the day but in relatively small portions. It seems that consuming about 25 grams (1 oz) of protein in all three or four evenly spaced meals in a day is the best strategy to build or retain muscle. This results in an overall daily protein intake of around 100 grams or 1.4 g per kilogram body weight. The table below shows how much of various foods we would need to eat to obtain that 25 g. You will see that for some foods you have to consume a lot of calories to get 25 g of protein so choose wisely! It is recommended that we should eat a variety of healthy protein foods because consuming a variety of high-protein food sources including seafood, lean meats and poultry, eggs, legumes, soy products, and nuts and seeds that provides about 15% of daily calories should ensure that daily protein requirements are met while avoiding excessive fat and calorie intake. Eating a diverse range of high protein foods also gives your body other important nutrients, including iron, zinc and B-group vitamins.

Blog #15: Do I Need To Take Any Supplements?

If people follow the guidelines for a healthy balanced diet then there is no need to take supplements of vitamins, minerals, essential fatty acids, or protein as all will be supplied in adequate amounts by such a diet. One possible exception is vitamin D which unlike all the other essential vitamins, is synthesized in the skin when sunlight exposure is adequate. Most of the vitamin D in the body is produced internally this way, and only a small proportion normally comes from the diet. Therefore, in the winter months, when the strength of the sun in many plces (e.g. in the UK and other Northern European countries, the northern states of the USA and Canada) is insufficient to produce vitamin D in the skin, a daily supplement of 1000 IU (25 micrograms) of vitamin D3 is desirable to maintain vitamin D status at its peak summer-time levels. Other situations where a supplement might be considered are as follows: (1) When a person is consuming a low energy diet in order to lose weight, then a daily multivitamin tablet can be taken to ensure that no deficiencies occur during the period of restricted food intake. (2) Caffeine in a dose of 1-3 mg per kg body weight can help to reduce perceived effort during exercise lasting an hour or more. This can be taken as a supplement using 50 mg tablets, but enough caffeine is contained in a cup of strong coffee to supply the required dose. This should be drunk about one hour before exercise for optimal effect. (3) Probiotics are “friendly” live bacteria which when ingested in sufficient amounts, modify the gut microbial population (called the microbiota) and can have some beneficial health effects. Probiotics are a particularly useful supplement to take after a course of antibiotic medication (usually prescribed to treat bacterial infections), as many antibiotics destroy a significant proportion of the microbiota. Taking probiotics at this time ensures that the microbiota is restored with good bacteria rather than bad ones. There is some scientific evidence that certain probiotics can also reduce the incidence of respiratory and gastrointestinal infections making them a potentially useful daily supplement for individuals who are particularly prone to infection. Athletes will often take these sorts of supplements to help maintain health or boost their performance. They may also take other supplements like creatine, beta-alanine and beetroot juice to im prove performance or delay fatigue. Of course, there are very many other supplements that companies are trying to persuade us to take for a variety of reasons but the reality is that these are not needed and there is often very little evidence of efficacy. So don’t waste your money on them unless advised to take them by your healthcare practitioner or a qualified nutritionist or dietitian.

Blog #16: What You Can Eat And What You Can Do To Avoid The Coronavirus

WHAT YOU CAN EAT AND WHAT YOU CAN DO TO REDUCE YOUR RISK OF BECOMING INFECTED WITH RESPIRATORY PATHOGENS LIKE THE CORONAVIRUS

An immediate concern of everyone at the moment is the risk of becoming infected with the coronavirus and as it is still winter in the northern hemisphere there is also the increased risk of picking up other respiratory tract infections such as influenza and the common cold which are also caused by viruses. The symptoms of these illnesses have some similarities but also some differences: Infection with coronavirus is characterized by having a fever and developing a dry tickly cough; having a sore throat and a runny nose are less common. Influenza also causes a fever, aching joints and has symptoms similar to (but usually more severe than) the common cold which include a runny nose, sore throat and sneezing. We generally do not get a fever with the common cold. Most people who get these infections will recover within one to two weeks but they make you feel weaker, tired and generally unwell while symptoms are present. Among the elderly, the infection can be more debilitating, and they have an increased risk of developing more serious complications such as chest (lung) infections, including bronchitis and pneumonia which can be fatal particularly in people with underlying medical conditions such as hypertension, heart disease, lung disease and diabetes.

Our immune system protects us against the viruses that cause these infections, but because there is a genetic influence on the efficacy of our immune systems, some people are more prone to infections than others. However, our susceptibility to common infectious diseases is also influenced by what we eat, how much exercise we do, and how well we sleep. In addition, other lifestyle behaviors such as good personal hygiene practices can help to reduce our risk of picking up infections. This article explains the various nutritional, behavioral, and lifestyle strategies that we can easily implement to help minimize our risk of respiratory tract infections.

There are two main factors that influence our chance of picking up a respiratory tract infection: one is the degree of exposure to pathogens like coronavirus and the other is the status of our immune system. We can reduce our risk of infection by doing various things that limit the transmission of infections and there are several behavioral and nutrition strategies that we can do to help make our immune systems more robust.

Some practical guidelines for limiting transmission of infections among people are listed below. The most important of these are good hand hygiene and avoiding contact with persons that are infected. Hand washing (using the correct technique for about 30 seconds to ensure all parts of hands are cleaned effectively) with soap and water is effective against most pathogens but does not provide continuous protection. Hand gels containing a minimum of 60% alcohol disinfect effectively, but the protection they provide does not last more than a few minutes, so they need to be applied frequently, and this can cause dry skin and irritation. Other sanitization methods include the use of non-alcohol based antimicrobial hand foams that contain cationic biocides and hydrophobic polymers which are claimed to disinfect hands for up to six hours. However, individuals need to be aware that these products are removed by hand washing and excessive sweating, therefore they also need to be reapplied every few hours.

Behavioral and lifestyle strategies to limit transmission of infections:

Minimize contact with infected people, young children, animals, and contagious objects.

Avoid crowded areas and shaking hands.

Keep your distance from people who are coughing, sneezing, or have a ‘runny nose’, and when appropriate, wear (or ask them to wear) a disposable mask.

Wash hands regularly and effectively with soap and water, especially before meals, and after direct contact with potentially contagious people, animals, blood, secretions, public places, and bathrooms.

Use disposable paper towels and limit hand to mouth/nose contact (putting hands to eyes and nose is a major route of viral self-inoculation).

Carry anti-microbial foam/cream or alcohol-based hand-washing gel with you.

Do not share drinking bottles, cups, cutlery, towels, etc. with other people.

When abroad, choose cold beverages from sealed bottles, avoid raw vegetables and undercooked meat. Wash and peel fruit before eating.

The other things that people can do to limit their risk of infection are to adhere to some practical guidelines to maintain robust immunity and limit the impact stress which is known to impair the functioning of our immune system and increase susceptibility to respiratory infections. These guidelines are listed below and relate mostly to nutritional, behavioral, and lifestyle strategies and are based on the findings of numerous research studies. The most effective nutritional strategies to maintain robust immune function are to avoid deficiencies of essential micronutrients, ingest Lactobacillus probiotics on a daily basis, and eat plenty of fruit and vegetables. Probiotics are live bacteria which when ingested in adequate amounts, modify the bacterial population (known as the microbiota) that inhabits our gut and modulate immune function by their interaction with the gut-associated lymphoid tissue, leading to positive effects on the systemic immune system. Some well-controlled studies in children, adults, endurance athletes, and the elderly have indicated that daily probiotic ingestion results in fewer days of respiratory illness and lower severity of infection symptoms.

Some studies suggest that regular consumption of fruits and plant polyphenol supplements (e.g., quercetin) or beverages that contain high amounts of polyphenols (e.g., non-alcoholic beer and green tea) can also reduce common cold incidence. Ensuring that the individual has adequate vitamin D may also be helpful, and supplementation with vitamin D3 (1,000-4,000 IU/day or 25-100 micrograms (µg)/day) may be warranted for some people, especially in the winter months for those living at latitudes of 48°North (equivalent to Paris, France and the USA-Canada border) and above since the skin is unable to form vitamin D between the months of October through to March because the sunlight is not strong enough. Many other nutrition supplements, including β-glucan, echinacea, glutamine, colostrum and others, are on sale with claims that they can boost the immune system, but the scientific evidence that any of these are effective in preventing infections is not compelling. When respiratory illness symptoms begin, there is some evidence that taking zinc lozenges (>75 mg zinc/day; high ionic zinc content) or certain herbal supplements (e.g., echinacea, ginseng, kaloba) can reduce the number of days that illness symptoms last for. However, these may not be any more effective than treating illness symptoms with over-the-counter cold remedies.

Nutritional and behavioral strategies to help maintain robust immunity:

If you participate in regular exercise, avoid very prolonged training sessions (longer than two hours) and excessive periods of intensified training as this can depress your immunity.

Wear appropriate outdoor clothing in inclement weather, and avoid getting cold and wet after exercise.

Get adequate sleep (at least seven hours per night is recommended). Missing a single night of sleep has little effect on immune function at rest or after exercise, but respiratory illness episodes are more prevalent in those who regularly experience low sleep quantity (less than seven hours per night) and poor sleep quality (frequent awakenings).

Keep other life stresses to a minimum.

Ensure adequate dietary energy, protein, and essential micronutrient intake.

Vitamin D plays an important role in promoting immunity, and this is a concern as vitamin D insufficiency is common in people especially in situations where exposure to natural sunlight is limited (e.g., during the winter months or when living or working mostly indoors). A vitamin D3 supplement (1,000-4,000 IU/day or 25-100 µg/day) may be beneficial to optimize immune function from October to April in Northern hemisphere countries.

Avoid crash dieting and rapid weight loss. Care should be taken to ensure adequate protein (and micronutrient) intakes during periods of intentional weight loss, as individuals undergoing weight reduction are likely to be more prone to infection. In general, a broad-range multivitamin/mineral supplement is the best choice to support a restricted food intake, and this may also be suitable when travelling abroad in situations where food choices and quality may be limited.

Eat several different fruits daily at least five times per week as regular fruit intake is associated with a lower incidence of the common cold.

If you plan to do a prolonged (90 minutes or more) moderate to high intensity exercise session, ensure adequate carbohydrate intake before and during exercise in order to limit the extent and severity of exercise-induced immune depression. Ingesting about 40 g carbohydrate per hour of exercise during prolonged workouts maintains blood sugar levels and lowers circulating stress hormones and so helps to limit immune function depression. A 500 mL bottle of a sports drink usually contains 30-40 g of carbohydrate.

The consumption of beverages during exercise not only helps prevent dehydration (which is associated with an increased stress hormone response) but also helps to maintain saliva flow rate during exercise. Saliva contains several proteins with antimicrobial properties including immunoglobulin A, lysozyme, a-amylase, and defensins. Saliva secretion usually falls during exercise, but regular fluid intake (water is fine) during exercise can prevent this.

The efficacy of most so-called dietary immunostimulants has not been confirmed. However, there is limited evidence that some flavonoids (e.g., quercetin at a dose of 1 g/day) or flavonoid containing beverages (e.g., non-alcoholic beer, green tea), and Lactobacillus and/or Bifidobacterium probiotics (daily doses of ~10¹⁰ live bacteria) can reduce respiratory infection incidence in physically active people or those under stress. Another potential benefit of probiotics could be a reduced risk of gastrointestinal infections – a particular concern when travelling abroad.

High daily doses (up to 1000 mg) of vitamin C are not generally justified, but individuals engaged in intensive training and/or cold environments may gain some benefit for preventing respiratory infections.

Avoid strenuous exercise for a few days when experiencing upper respiratory symptoms like sore throat, sneezing, runny, or congested nose. Avoid all exercise other than walking when experiencing symptoms like muscle/joint pain and headache, a chesty cough, fever (indicated by a resting body temperature of 38-40°C), and generalized feeling of malaise, diarrhea, or vomiting. Some light exercise like walking may be beneficial to help avoid fluid accumulation in the lungs which increases the risk of developing dangerous complications like pneumonia.

You may be asked to self-isolate for up to 14 days if you experience respiratory illness symptoms and this advice is generally for the protection of others by limiting virus transmission. After your symptoms resolve, start to do some light to moderate exercise around the home and the garden.

Blog #17: Lifestyle behaviours to beat COVID-19 and improve your vaccination response

WHY A HEALTHY DIET, REGULAR EXERCISE AND GETTING A GOOD NIGHT'S SLEEP CAN HELP YOU RESIST COVID-19, HELP YOU FIGHT IT IF YOU GET INFECTED, AND INCREASE YOUR ANTIBODY RESPONSE TO VACCINATION

In the past 12 months we have all been told about some of the ways in which we can reduce our risk of picking up respiratory infections, particularly COVID-19. Social distancing, face masks and hand sanitisation have all become familiar terms. But there is more to learn as it has become clear that risk of serious health problems, respiratory failure and death following COVID-19 infection is more common in people who are overweight or unfit. So if that applies to you it makes sense to try to lose some of those excess pounds by some sensible dieting and doing some more exercise which will also improve your fitness. Our various lifestyle behaviours including our daily exercise habits, diet and sleep quality can also influence our infection risk and the health outcomes if we do become infected. They may also have an impact on our response to vaccination. Here I explain some of the reasons and suggest some strategies to help people get through this current viral pandemic nightmare in a healthy state. Let’s begin with what we eat.

Emerging research on COVID-19 patients, and numerous previous studies relating to other viral respiratory infections, suggests key nutrients and supplements such as probiotics, selenium, vitamin D and zinc, may boost your immune system if you are not already getting enough in your diet, limit the severity of coronavirus infection symptoms and even reduce intensive care admissions and mortality rates. Undoubtedly, the most important thing to help you maintain a robust immune system is to avoid any deficiencies of protein and essential vitamins and minerals. We can get all we need from a healthy, diverse and well balanced diet that is sufficient to meet our energy needs. Such a diet, containing meat, fish and lots of fruit and non-starchy vegetables will also ensure that we have a healthy gut microbiota which also helps our immune defences.

Although the existing data requires further research, the results so far are promising: Recent research studies indicate that patients who survived COVID-19 had higher levels of selenium – a nutrient found in eggs, liver, kidney, nuts, sardines and turkey – than those who died of the virus. Other studies have reported that healthy levels of zinc – a mineral found in cheese, meat, poultry, seeds and shellfish – are linked to higher survival rates. Several studies have reported that the vast majority of hospitalised coronavirus patients were deficient in vitamin D, which we gain mostly through exposure to the sun which is compromised in the winter months when infection rates from respiratory viruses including COVID-19 are the highest. And a few studies have now reported that daily consumption of probiotics reduced the severity of COVID-19 symptoms and cut mortality rates.

Nutrition is very important, not only for ‘resistance’ in protecting you from getting respiratory infections like the common cold, influenza and COVID-19 but also for improving your ‘tolerance’ of it. Tolerance means a decreased infection burden when you get infected, so you could get less severe symptoms and recover more quickly. That’s the possible role of nutrition. We're talking about compounds that are in our normal diet (or can be supplemented in tablet form) which may optimise the immune response or have beneficial anti-inflammatory or antioxidant actions.

Unfortunately, it seems likely that nothing you eat is actually going to stop you contracting COVID-19. This virus is so contagious it seems to be able to easily bypass our immunity barriers. But a strong immune system will inevitably help you to fight it more effectively and be less susceptible to getting severe symptoms that can lead to death. We rely upon our immune response to respond appropriately when we get infected. And if you're deficient in micronutrients like iron, selenium, zinc or vitamins C, D and E, it may increase your risk of severe symptoms.

Your body’s immune response to any virus requires a delicate balancing act: if your immune response is too low, your body’s defences will be overwhelmed. But if your immune response is too high, the defensive processes against COVID-19 can cause excessive inflammation, fluid accumulation in the lungs, breathing difficulties and multiple organ damage that can be fatal. Our immune system gets rid of viruses by seeking out your own cells which have become infected and destroying them so there's a real balance needed in your immune response. You want to be able to tolerate the virus, to some degree, in order to dampen your defence a little bit but still control the infection in order to reduce the risk of acute respiratory distress syndrome (when the lungs cannot provide the vital organs with enough oxygen) which can develop if you get too much inflammation in the lungs.

So how might some of these key nutrients help your body produce the most appropriate immune response? Research suggests selenium (an essential cofactor for several enzymes important in antioxidant defence) helps to adeptly refine your immune response and you get less severe inflammation if you have a good selenium status. There is evidence that you also get improved proliferation of your lymphocytes (an important type of white blood cell) which help to activate the cell lines that specifically respond to a virus. Another essential mineral in our diet, zinc, is very important in helping to prevent viruses from proliferating. Viruses have a protective coat which surrounds their genetic material and the first thing they do when they get into your cells is un-coat themselves, release their genetic material and take over your own molecular machinery to help generate other viruses within your cells. But zinc helps to block that viral un-coating, as well as inhibiting the enzyme which allows that genetic material to be reproduced in the cell, so it helps to prevent a virus from proliferating in your body giving your immune cells time to respond and destroy it.

Probiotics may also play an important role because your gut is a key part of your immune system. Probiotics can modify immune cells in the gut which can then migrate to other areas, including the lungs – and this may be where you get some protection. Studies indicate that taking a daily probiotic supplement can reduce the incidence of respiratory infections and reduce the severity and duration of symptoms if you do get infected.

Vitamin D plays a key regulatory role in immunity. We know from studies on the common cold that with low vitamin D status you're more likely to pick up respiratory viral infections. Although 10mg is the recommended daily dose, if you’ve not had much sun for months (like now in the winter) that’s not enough to get you up to the levels you want for optimal immune function, so I suggest a daily dose of at least 25mg or 1000IU of vitamin D3. We can get most of the other immunity-optimising nutrients from our everyday diet. As well as the foods listed above, nuts, cod and wholegrains also contain selenium (the RDA is 75μg for men and 60mg for women); beef, dairy and spinach also provide zinc (the RDA is 9.5mg for men and 7mg for women); and a healthy mix of fruit and vegetables will promote your population of healthy gut bacteria, which can be topped up with probiotics.

What is more is that improving your diet may even help you get a better protective antibody response to your COVID-19 vaccine. We know that with vaccines like the one for the influenza virus, selenium and vitamin D are linked to stronger antibody responses to the vaccination and it seems likely that this will also be the case for COVID-19. And if lockdown and stress have been driving you to drink more alcohol, then beware: binge drinking has been shown to depress the functions of your immune cells. Try non-alcoholic beer instead which contains health-promoting polyphenols which have antioxidant actions and appear to improve immune defence.

What about exercise which if done regularly seems to protect against adverse health outcomes with COVID-19 infection and can boost your antibody production in response to vaccination, particularly in the elderly? People who regularly engage in moderate intensity physical activities like walking, jogging and cycling are known to get fewer respiratory infections than sedentary coach potatoes. Scientists believe the reason for that is that when we exercise we flush lots of additional white blood cells (WBCs) into our circulation from places where they are normally stored in the body: the bone marrow, spleen and thymus gland and we also release WBCs that have been stuck to the inner lining of our blood vessel walls. Some of the WBCs that enter our blood circulation during exercise are specialised T lymphocytes that are primed to fight infections and after exercise they move into our lungs, gut and lymph glands to seek out and destroy pathogens. So exercise essentially improves what we call immune-surveillance.

Another benefit of regular exercise and being reasonably fit is that it helps to keep us lean by burning calories and, most importantly, it dampens down inflammation – the thing that can generate severe health problems during COVID-19 infection. In contrast if you are sedentary and overweight your adipose (fat) tissue becomes inflamed and you develop what is called chronic (long-lasting) low grade inflammation which primes your body to produce an excessive pro-inflammatory response to infection and tissue damage. That is just what you don’t want if you get infected with COVID-19. Exercise has various anti-inflammatory effects which is one of the main reasons why exercise is also protective against the development of many chronic diseases including type 2 diabetes, high blood pressure, coronary heart disease, dementia and several cancers. If you are getting bored and fed up with lockdown it is good to know that doing some enjoyable physical activity can also boost your mood, relieve depression and improve your mental wellbeing. As mentioned previously doing some exercise before you have your vaccination can improve your antibody response to it giving you greater protection against possible future infection with COVID-19. So have a 30-minute jog or a brisk walk before you go to the vaccination centre if you can.

Sleep – how much we get on average each night and sleep quality (the fewer awakenings you get during the night is considered good) – also affects your immune system and has been shown to influence your risk of developing an infection when exposed to a respiratory virus. People who are least likely to develop infections are those who get more than seven hours sleep each night and are asleep for over 95% of the time after lights out at bedtime until morning. There are a number of things you can do to help you get a good night’s sleep including having a regular times for going to bed and waking up, relaxing before bedtime, having a dark, quiet, warm sleeping environment (not too warm though, a bedroom temperature of 15-19°C is usually best for sleeping well) and a comfortable bed with an appropriate duvet tog rating for the time of year and cotton sheets. You should also avoid caffeine, nicotine, exercise, heavy meals and drinking alcohol or large volumes of fluid for a few hours before going to bed. Oh and do try to resist the temptation to look at your mobile phone or tablet after getting into bed and try to forget about your worries until morning.

So there you have it…what we EAT, how much we MOVE and how well we SLEEP affects our infection risk and our response to respiratory infections like COVID-19 (and others like influenza and the common cold). These lifestyle behaviours also have important implications for our overall long-term health and longevity. You can find out much more about this and helpful strategies to help make your health optimal – that is the best it can be – in my healthy lifestyle guidebook EAT, MOVE, SLEEP, REPEAT published by Meyer & Meyer Sport last year. And if you are looking for ways to lose some excess weight but don’t fancy the idea of sticking to one boring diet for weeks on end then my latest book THE PICK ‘N MIX DIET is for you. Both books are available as paperback or eBook from Amazon and other online book sellers.