Kurzgesagt – In a Nutshell
Sources – Milk
We would like to thank the following experts for their scientific support:
- Dr. Malte Rubach
Nutritionist & Author, M.R.EXPERT
- Simone Hörrlein
Food chemist, Nutrition expert & Science journalist
- Anonymous
Docent of nutrition science
Sources:
– Over the last decade milk has become a bit controversial.
These articles offer a good overview on controversial findings on health effects associated with the consumption of milk and dairy:
#All about milk, 2017
https://www.medicalnewstoday.com/articles/273451.php
#Personal health; Debate Over Milk: Time to Look at Facts, 2000
Quote: “Hardly a month passes without another accusation hurdled at milk as less than an ideal food. Among recent claims: milk can cause juvenile diabetes, heart disease, cancer, digestive disorders, ear infections, mucus in the throat and, in infants, allergies, colic and iron deficiency anemia.”
– Some people say it’s a necessary and nutritious food, vital for healthy bones...
#Milk and other dairy foods are good for bone health, 2016
https://www.iofbonehealth.org/news/milk-and-other-dairy-foods-are-good-bone-health
Quote: “Evidence strongly supports the benefits of dairy products for bone and muscle health. Studies have shown that bone loss is reduced and there is an improvement in muscle mass and strength with adequate dairy intake.”
#All about milk, 2017
https://www.medicalnewstoday.com/articles/273451.php
Quote: “Milk is good for the bones because it offers a rich source of calcium, a mineral essential for healthy bones and teeth. Cow's milk is fortified with vitamin D, which also benefits bone health. Calcium and vitamin D help prevent osteoporosis.”
– … but others say it can cause cancer and lead to an early death.
#Dairy products, calcium, and prostate cancer risk: a systematic review and meta-analysis of cohort studies, 2015
https://www.ncbi.nlm.nih.gov/pubmed/25527754/
Quote: “High intakes of dairy products, milk, low-fat milk, cheese, and total, dietary, and dairy calcium, but not supplemental or nondairy calcium, may increase total prostate cancer risk.“
#Risk factors for prostate cancer, retrieved 2019
https://www.cancer.ca/en/cancer-information/cancer-type/prostate/risks/?region=on
Quote: “There is some evidence that diets high in dairy products and calcium may increase the risk of prostate cancer. Milk, yogurt and cheese are examples of dairy products and are also foods high in calcium.”
– Milk is the basis of every mammal's diet after birth.
The Swedish biologist Carolus Linnaeus gave mammals their name based on the Latin word mamma, meaning breast. All mammals have in common that drink their mother’s milk right after birth.
#Why did some animals evolve milk and breastfeeding?, 2015
http://www.bbc.com/earth/story/20150725-breastfeeding-has-ancient-origins
Quote: “Linnaeus called these animals the Mammalia, meaning "of the breasts". Nowadays we tend to call them "mammals", and they really do all produce milk.”
#Breastfeeding Is a Dynamic Biological Process—Not Simply a Meal at the Breast, 2011
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3199546/
Quote: “Among mammals, breastfeeding has evolved over millions of years as a multitiered interaction to meet the biological and psychosocial needs of the progeny, enhancing its well-being and survival chances, as well as complementing the nurturing role of the mother.”
– Milk is rich in fat, minerals, vitamins, and milk sugar: Lactose.
Since this source is picked from the book, we can’t provide an online link here.
#Souci-Fachmann-Kraut, Food Composition and Nutrition Tables, 2016
The official report by the Food and Agriculture Organization of the United Nations (FAO) on milk and dairy contains a table of the composition of different types of milk on page 44 et seq.
#Milk and dairy products in human nutrition, 2013
http://www.fao.org/3/i3396e/i3396e.pdf
– On top of that, for a while after birth it also contains antibodies and proteins that protect us from infections and regulate our immune system.
#Human Milk Composition: Nutrients and Bioactive Factors, 2013
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3586783/
Quote: “Infants are born with immature acquired immunity, and rely on maternal antibodies for defense against pathogens. Human milk sIgA-antigen complexes are taken up and processed by intestinal dendritic cells, which allows for antigen recognition while maintaining a non-inflammatory environment”
– But it is a lot of effort for mothers to produce.
With “effort” we are referring to energy. A mother who exclusively breastfeeds her baby spends 20-30% of her resting energy on milk production.
#Normal Human Lactation: closing the gap, 2018
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6013763/
Quote: “Therefore, for mothers exclusively breastfeeding their babies, it can be calculated that the energy output in human milk accounts for about 20% to 30% of the maternal resting energy requirement”
– Eventually humans stop drinking mother’s milk and transition to the diet of their parents.
Starting from one year of age it’s common for babies to gradually stop breastfeeding. But they still can be nursed even up to toddler age.
#Frequently Asked Questions (FAQs), 2018
https://www.cdc.gov/breastfeeding/faq/index.htm
Quote: “WHO also recommends exclusive breastfeeding up to 6 months of age with continued breastfeeding along with appropriate complementary foods up to 2 years of age or longer.”
– Until about 11,000 years ago, when our ancestors settled down in the first agricultural communities.
#The milk revolution – When a single genetic mutation first let ancient Europeans drink milk, it set the stage for a continental upheaval, 2013
https://www.nature.com/news/archaeology-the-milk-revolution-1.13471
Quote: “But as farming started to replace hunting and gathering in the Middle East around 11,000 years ago, cattle herders learned how to reduce lactose in dairy products to tolerable levels by fermenting milk to make cheese or yogurt. “
– But the older we grow, the less lactase enzymes our body produces.
#The milk revolution – When a single genetic mutation first let ancient Europeans drink milk, it set the stage for a continental upheaval, 2013
https://www.nature.com/news/archaeology-the-milk-revolution-1.13471
Quote: “Young children almost universally produce lactase and can digest the lactose in their mother's milk. But as they mature, most switch off the lactase gene. Only 35% of the human population can digest lactose beyond the age of about seven or eight “
Not only do we produce less lactase enzymes during adulthood, but the remaining ones are also less active.
#Changing genes; losing lactase, 2003
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1773627/
Quote: “Before week 24 of gestation, intestinal lactase activity is low. It then begins to increase, and during the third trimester lactase activity increases markedly until levels in term neonates are at or above those of infants aged 2–11 months.”
#Recent advances on lactose intolerance: Tolerance thresholds and currently available answers, 2015
https://www.tandfonline.com/doi/abs/10.1080/10408398.2015.1123671
Quote: “The genetically programmed reduction in lactase activity during adulthood affects 70% of the world adult population”
– Worldwide about 65% of the population do not have the enzyme after infancy. […] In some East Asian communities for example it is up to 90%. In Northern Europe and North America the rates [of lactose intolerance] are the lowest overall.
These numbers always shift a bit, due to the permanent changes in death and birth rates. But in most studies the number scientists pick for their calculations lies between 65 and 70%.
#Prehistoric man and lactose intolerance, 2013
#Lactose intolerance, 2019
https://ghr.nlm.nih.gov/condition/lactose-intolerance#statistics
Quote: “Approximately 65 percent of the human population has a reduced ability to digest lactose after infancy.”
#Lactase Non-persistence and Lactose Intolerance, 2017
https://link.springer.com/article/10.1007/s11894-017-0558-9
Quote: “[The purpose of this review is] to evaluate the clinical and nutritional significance of genetically determined lactase non-persistence and potential lactose and milk intolerance in 65–70% of the world’s adult population.”
#The milk revolution – When a single genetic mutation first let ancient Europeans drink milk, it set the stage for a continental upheaval, 2013
https://www.nature.com/news/archaeology-the-milk-revolution-1.13471
Quote: “Only 35% of the human population can digest lactose beyond the age of about seven or eight”
#Lactose malabsorption and intolerance: pathogenesis, diagnosis and treatment, 2013
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4040760/
Quote: “Prevalence of lactase persistence is high in most regions in Scandinavia, the British islands, and Germany (80–95%); however, this condition is observed in only 20–40% of Indian adults, 30% of Mexicans, 30% of African Americans, and <10% of adults in Southeast Asia.”
– Some older studies found a connection between milk and a higher risk of breast, colon and prostate cancer.
#Patterns of milk consumption and risk of cancer, 1989 ; published online in 2009
https://www.tandfonline.com/doi/abs/10.1080/01635589009514049
Quote: “As a group, control patients [patients without cancer] were more likely to report never drinking whole milk; cancer patients more often reported frequent consumption of whole milk. “
– But Meta analyses found no impact on your cancer risk.
#Milk consumption in relation to incidence of prostate, breast, colon, and rectal cancers: is there an independent effect?, 2005
https://www.ncbi.nlm.nih.gov/pubmed/16351508
Quote: “The present study does not support an overall substantial effect of milk consumption on the risk of prostate, breast, colon, and rectal cancers at the population level.”
#Milk, yogurt, and lactose intake and ovarian cancer risk: a meta-analysis, 2014
https://www.ncbi.nlm.nih.gov/pubmed/25298278
Quote: “This meta-analysis suggests that low-fat/skim milk, whole milk, yogurt and lactose intake has no associated with increased risk of ovarian cancer. Further studies with larger participants worldwide are needed to validate the association between dairy food intake and ovarian cancer.”
#Dairy products and pancreatic cancer risk: a pooled analysis of 14 cohort studies, 2015
https://www.ncbi.nlm.nih.gov/pubmed/24631943
Quote: “Overall, these findings do not support the hypothesis that consumption of dairy foods, calcium, or vitamin D during adulthood is associated with pancreatic cancer risk.”
Some studies even suggest that milk and dairy intake decreases cancer-risk. But the evidence is rather weak and needs further research:
#Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective, 2007
https://www.wcrf.org/dietandcancer/exposures/meat-fish-dairy
Quote: “The CUP Panel concluded that the evidence was generally consistent for dairy
products, milk, cheese and dietary calcium, and showed a decreased risk of colorectal
cancer with higher consumption.”
#Milk consumption and bladder cancer risk: a meta-analysis of published epidemiological
studies, 2011
https://www.ncbi.nlm.nih.gov/pubmed/22043867
Quote: “Our results suggest that milk may be related to the reduction of bladder cancer risk. Further studies need to clarify the biological mechanisms.”
#Dairy consumption and risk of breast cancer: a meta-analysis of prospective cohort studies, 2011
https://www.ncbi.nlm.nih.gov/pubmed/21442197
Quote: “In conclusion, findings of the present meta-analysis indicate that increased consumption of total dairy food, but not milk, may be associated with a reduced risk of breast cancer.”
#Dairy consumption and gastric cancer risk: a meta-analysis of epidemiological studies, 2015
https://www.ncbi.nlm.nih.gov/pubmed/25923921
Quote: “The results of cohort studies, but not case-control studies, suggested that total dairy might be related to the reduction of gastric cancer risk. Milk consumption was not associated with gastric cancer risk.”
– On the contrary, the calcium in milk might even have a protective effect against colon cancer.
#Dairy products and colorectal cancer risk: a systematic review and meta-analysis of cohort studies, 2012
https://www.ncbi.nlm.nih.gov/pubmed/21617020
Quote: “This meta-analysis shows that milk and total dairy products, but not cheese or other dairy products, are associated with a reduction in colorectal cancer risk.”
#Colorectal Cancer and Nonfermented Milk, Solid Cheese, and Fermented Milk Consumption: A Systematic Review and Meta-Analysis of Prospective Studies, 2014
Quote: “This meta-analysis supports the inverse association between nonfermented milk consumption and risk of colon cancer in men, and provides an evidence base to assist in the formulation of dietary guidelines involving dairy foods.”
– Only studies on prostate cancer showed an increased risk for people who consumed more than 1.25 liters of milk a day, but again the association is inconsistent and other studies didn't find any effect.
The results from these studies are correlations based on the stratification of the study population, that means the formation of different layers of people that depend on where they get their protein from (animal or plant and which animal or plant exactly). But this only works with a relevant amount of data. Since it is impossible to cover the entire population, such results have to be taken with a grain of salt. First of all they only represent a cutout and also they only show statistical correlations, which is not the same as rock-solid proof.
Here are a couple of studies that found a connection:
#Etiology of prostate cancer (C61) in Central and South America, 2016
https://gco.iarc.fr/includes/CSA_Chp_4-10_Prostate.pdf
Quote: “The World Cancer Research Fund/American Institute for Cancer Research [27] reviewed the evidence regarding the relationship between several foods and nutrients and the risk of cancer and found that diets high in calcium (i.e. > 1.5 g per day) increased the risk of prostate cancer by 27% (95% CI, 9–48% per g per day) (meta-analysis of 8 cohort studies with moderate heterogeneity) and that of advanced and aggressive prostate cancer by 32% (95% CI, 5–64% per g per day) (meta-analysis of 4 cohort studies with moderate heterogeneity). However, a meta-analysis of observational studies indicated that consumption of dairy products was not associated with an increased risk of prostate cancer [28].”
#Food, Nutrition, Physical Activity, and the Prevention of Cancer, 2007
https://discovery.ucl.ac.uk/id/eprint/4841/1/4841.pdf
Quote: “Effect only apparent at high calcium intakes (around 1.5 g/day or more). Evidence for milk and dairy products (but not calcium) was derived only from data for countries with populations that have high calcium and dairy consumption”
The report noted a significance for calcium from dairy, if the intake was more than 1.5 g/day. Since a liter of milk typically contains about 1.25 g, this would be 1.25 L of milk per day.
This study found a connection for dairy protein from more than one liter per day.
#Animal foods, protein, calcium and prostate cancer risk: the European Prospective Investigation into Cancer and Nutrition, 2008
https://www.ncbi.nlm.nih.gov/pubmed/18382426
Quote: “After calibration to allow for measurement error, we estimated that a 35-g day(-1) increase in consumption of dairy protein was associated with an increase in the risk of prostate cancer of 32% (95% CI: 1-72%, P(trend)=0.04).”
35 g of dairy protein per day was connected to an increased cancer risk. Based on 3.5 g of dairy protein per 100ml of milk, you would have to drink at least one liter of milk per day to fall into this risk category. Since calcium was found as another risk factor in the same study if milk consumption exceeds 1,25 L and more, we decided to go with the more cautious threshold of 1.25 L for the video text.
This is an example for a study that didn’t find any effect:
#Milk consumption in relation to incidence of prostate, breast, colon, and rectal cancers: is there an independent effect?, 2005
https://www.ncbi.nlm.nih.gov/pubmed/16351508
Quote: “The present study does not support an overall substantial effect of milk consumption on the risk of prostate, breast, colon, and rectal cancers at the population level.”
And this one is the most recent meta-analysis:
#Milk and Dairy Product Consumption and Prostate Cancer Risk and Mortality: An Overview of Systematic Reviews and Meta-analyses, 2019
https://academic.oup.com/advances/article/10/suppl_2/S212/5489442
Quote: "In conclusion, although there are some data indicating that higher consumption of dairy products could increase the risk of prostate cancer, the evidence is not consistent."
– Similarly, meta analyses could not find any impact from milk or dairy products on your risk of heart disease, stroke or your total mortality.
Stroke:
#Dairy foods and risk of stroke: a meta-analysis of prospective cohort studies, 2014
https://www.ncbi.nlm.nih.gov/pubmed/24472634
Quote: “Dairy foods might be inversely associated with the risk of stroke.”
#The consumption of milk and dairy foods and the incidence of vascular disease and diabetes: an overview of the evidence, 2010
https://www.ncbi.nlm.nih.gov/pubmed/20397059
Quote: “Meta-analyses suggest a reduction in risk in the subjects with the highest dairy consumption relative to those with the lowest intake:”
Cardiovascular disease:
#Milk and Dairy Product Consumption and Cardiovascular Diseases: An Overview of Systematic Reviews and Meta-Analyses, 2019
https://academic.oup.com/advances/article-abstract/10/suppl_2/S164/5489436?redirectedFrom=fulltext
Quote: "Therefore, the present study states that the consumption of total dairy products, with either regular or low fat content, does not adversely affect the risk of CVD."
Total mortality:
#Food sources of saturated fat and the association with mortality: a meta-analysis, 2013
https://www.ncbi.nlm.nih.gov/pubmed/23865702
Quote: “Pooled relative risk estimates demonstrated that high intakes of milk, cheese, yogurt, and butter were not associated with a significantly increased risk of mortality compared with low intakes.”
– Some studies even suggested that high blood pressure might be more rarer in people who eat a lot of dairy, although the evidence is not strong enough to claim this with confidence.
#A Clinical Trial of the Effects of Dietary Patterns on Blood Pressure. DASH Collaborative Research Group, 1997
https://www.ncbi.nlm.nih.gov/pubmed/9099655
Quote: “A diet rich in fruits, vegetables, and low-fat dairy foods and with reduced saturated and total fat can substantially lower blood pressure.”
#A systematic review and meta-analysis of elevated blood pressure and consumption of dairy foods, 2016
https://www.ncbi.nlm.nih.gov/pubmed/21307883
Quote: “This meta-analysis supports the inverse association between low-fat dairy foods and fluid dairy foods and risk of EBP [elevated blood pressure]“
– The case gets more complicated though when we look at bones. A number of studies found neither a positive nor negative effect for adults.
Summary:
#Osteoporosis: Is milk a kindness or a curse?, 2017
https://www.ncbi.nlm.nih.gov/pubmed/27726930
Quote: “A close look at the scientific literature shows a striking contradiction. On the one hand, experimental studies of surrogate markers (e.g., bone turnover markers and bone mineral density [BMD]) usually indicate benefits from drinking cow's milk. On the other, the findings from epidemiological studies are conflicting and disconcerting.”
“To date, there is no conclusive evidence that we should modify our currently high level of consumption of cow's milk.”
Original study:
#Calcium intake and hip fracture risk in men and women: a meta-analysis of prospective cohort studies and randomized controlled trials, 2007
https://www.ncbi.nlm.nih.gov/pubmed/18065599?dopt=Citation
Quote: “For any nonvertebral fractures, there was a neutral effect in the randomized trials.”
– There are hormones in milk but only in very low concentrations.
#Questions and Answers on Hormones in Meat and Milk, 2014
https://www.bfr.bund.de/en/questions_and_answers_on_hormones_in_meat_and_milk-191516.html
Quote: “The natural estrogens include estrone and in particular estradiol as important representatives of this group. In full-fat milk (fat content 3.5%), total concentrations are given as 0.13 micrograms of estrone and less than 0.02 micrograms of estradiol per kilogram of milk.”
– For example, to get the same amount of hormones as from the pill, you would need to drink about 5,000 litres of milk.
Let us clarify this number a bit here. When we talk about estrogen, we refer to a whole group of single hormones. One of them which constantly (and naturally) appears in milk is 17β-estradiol.
In anti-baby pills you find (next to other hormones like gestagen) a synthetic version of estradiol: ethinylestradiol. So we picked these two hormones (estradiol and ethinylestradiol), since they are the best to compare.
The hormone values in milk will differ from source to source. This is because the hormone levels change during the lactation cycle of a cow depending on how many weeks she is pregnant. Also, it makes a difference, whether the hormone levels are analyzed in processed or unprocessed milk.
At this point we would like to thank the staff of the German Federal Institute for Risk Assessment, who explained and confirmed this claim for us.
See Figure 4 from this study:
#Effect of dry period management on mammary gland function and its endocrine regulation in dairy cows, 2011
So we picked a source that analyzes a type of milk you would find on the supermarket shelf and not directly from the cow, to represent a more realistic scenario:
#Possible health impact of animal oestrogens in food, 2001
Quote:
“The mean concentration of oestradiol-17 in whole milk is estimated at 6.4 pg/ml.”
This source looks at bulk milk, the milk of many cows combined. This is how it’s usually transported and packaged. Also we took the value for processed whole milk, since we thought this is the most likely to be consumed by most of our viewers.
According to the source, there are 6.4 pg (pikogram) of estradiol per 1 mL of processed whole milk. This means there are overall 6,400 pg in one liter. So far, so good.
When it comes to anti-baby-pill, the highest doses of ethinylestradiol we found during research contained 0,05 mg, which equals 50,000,000 pg (pikogram). But these concentrations are rare and are rather found in old versions of the pill. The normal dose lies between 35,000,000 and 15,000,000 pg. 30,000,000-35,000,000 pg seemed to be the most commonly used.
#Choosing a combined oral contraceptive pill, 2015
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4654044/
Quote: “A key advance was a decrease in the dose of oestrogen to the currently used low-dose formulation (standard dose of ≤35 microgram ethinyloestradiol).”
#Needs and preferences of women users of oral contraceptives in selected countries in Central and Eastern Europe, 2018
If we divide the pill concentrations by 6,400, we can calculate the amount of milk you would have to drink to match the hormone dose from the pill:
Please note that this is just an example. The amounts shown above only apply to one hormone and one type of milk. But this hopefully demonstrates the scales which we are talking about regarding milk hormones.
– And even if you did, most hormones would be destroyed by your digestive system before they could affect you.
#Questions and Answers on Hormones in Meat and Milk, 2014
https://www.bfr.bund.de/en/questions_and_answers_on_hormones_in_meat_and_milk-191516.html
Quote: “Furthermore, the hormones are metabolised very quickly (pronounced “first pass” effect of the liver with peroral intake). The available scientific data do not currently give any reason to assume any relevant health risk.”
– For pesticides and antibiotics there are regulations in most parts of the world that only allow completely harmless amounts.
Pesticides:
The Food and Agriculture Organization of the UN (FAO) sets guidelines that are not binding, but respected in most countries:
#Pesticide residues in food, 2018
http://www.fao.org/3/CA2708EN/ca2708en.pdf
This report below from the UK is an example of what a food safety report may look like. Since many regions and countries have their own regulations and standards, these reports can vary a lot when it comes to methods and the thresholds for harming substances.
#Report on the pesticide residues monitoring programme: Quarter 3 2017
Quote: “72 [milk] samples contained no residues from those sought. None of the samples contained residues above the reporting level18 samples were labelled as organic. None contained residues from those sought”
#Pesticide Residue Monitoring Program Fiscal Year 2017 Pesticide Report, 2017
https://www.fda.gov/media/130291/download
Quote: "In FY 2017 (October 1, 2016 through September 30, 2017), FDA analyzed
6,069 human food samples(..) FDA found that 96.2% of domestic and 89.6% of import human foods were compliant with federal standards. (..) In FY 2017, FDA conducted pesticide analyses for two field assignments. In the first assignment, 550 domestic milk, shell eggs, honey, and game meat samples were analyzed for “Domestically Produced Animal-Derived Foods.” No residues were found in any of the milk or game meat samples, 87.5% of the egg samples, and 77.3% of the honey samples.”
This interactive map shows the results of the Analysis conducted by the European Food Safety Authority (EFSA): 0.4% of all the samples of cattle milk that were tested were above the maximum residue limit (MRL)
#Pesticide residues in food, 2016
https://www.efsa.europa.eu/en/interactive-pages/Pesticides-report-2016
Antibiotics in the EU:
This is the official law on antibiotic residue in the EU:
#Regulation (EC) No 853/2004 of the European Parliament and of the Council, 2004
https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32004R0853&from=EN
Quote of Article III, 4, a) on page 128: “Without prejudice to Directive 96/23/EC, food business operators must initiate procedures to ensure that raw milk is not placed on the market if either: (a) it contains antibiotic residues in a quantity that, in respect of any one of the substances referred to in Annexes I and III to Regulation (EEC) No 2377/90 *, exceeds the levels authorised under that Regulation;”
This report conducted by the European Union tested 13,168 different milk products. Only 0.08% were non-compliant:
#Report on the implementation of national residue monitoring plans in the member states in 2015
https://ec.europa.eu/food/sites/food/files/safety/docs/cs_vet-med-residues_workdoc_2015_en.pdf
Of the 1897 samples analysed by the US Food and Drug Administration (FDA), 0.78% were non-compliant:
#Milk drug residue sampling survey, 2015
This sheet offers an overview on possible dangers from pesticides:
#Toxicity of Pesticides, 2016
– Besides allergies and those suffering from lactose intolerance, the best known negative effects of milk are probably acne and general discomfort after drinking milk or eating dairy products.
#The effect of milk consumption on acne: a meta‐analysis of observational studies, 2018
https://onlinelibrary.wiley.com/doi/abs/10.1111/jdv.15204
Quote: “This meta‐analysis provides evidence of a positive association between milk consumption and acne risk.”
– For example, skimmed milk has been found to statistically increase the rate of acne by 24%
The number 24% comes from a meta-analysis of cohort studies and case-control studies, which means that people suffering from acne were asked about their eating habits.
#The effect of milk consumption on acne: a meta‐analysis of observational studies, 2018
https://onlinelibrary.wiley.com/doi/abs/10.1111/jdv.15204
Quote: “Compared with non‐consumers, the pooled OR was 1.16 for overall milk consumers in all included studies, and 1.17 (95% CI 1.10–1.24) in cohort studies and 1.16 (95% CI 1.09–1.24) in case–control or cross‐sectional studies. Subgroup analysis on milk forms determined a stronger association in skim milk consumers OR = 1.24.“
But there are no randomized controlled trials (RCT) on this topic. RCTs are the “gold standard” of the medical research methods. In these studies participants are picked randomly (or randomized) to avoid researchers consciously or unconsciously influencing the test results by picking certain candidates for the trial. This means that the results from the study cited above are not as solid as results from RCTs, which have not been conducted so far.
– Allergies against milk products are especially prevalent among children, with 1 in 18 kids in Germany suffering from them.
#Current status of allergy prevalence in Germany – Position paper of the Environmental MEdicine Commission of the Robert Koch Institute, 2016
– Milk, no matter if it comes from mothers, cows, sheep, goats or camels is a nutrient-dense food. It contains all necessary macronutrients and many micronutrients.
#Souci-Fachmann-Kraut, Food Composition and Nutrition Tables, 2016
– Especially for children it is a good way to get large amounts of calcium, and for vegetarians it is a good source of vitamin B12, and B-vitamins in general.
#Souci-Fachmann-Kraut, Food Composition and Nutrition Tables, 2016
One could argue that often vitamin B12 is added to the diet of the cows that can’t graze outside. So saying milk is healthy because it is “artificially enhanced” doesn’t count. This is only half the truth. The vitamin is indeed added to the cows fodder, but the cow itself can produce vitamin B12 in its stomach. So even if supplementation stops, B12 would still be in the milk.
What is true though, is that other vitamins, which are not from the “B”-group are reduced during pasteurisation and homogenisation.
#Vitamin B12 sources and microbial interaction, 2018
https://www.ncbi.nlm.nih.gov/pubmed/29216732
Quote: “In particular, the meat and milk of herbivorous ruminant animals (e.g. cattle and sheep) are good sources of vitamin B12 for humans. Ruminants acquire vitamin B12, which is considered an essential nutrient, through a symbiotic relationship with the bacteria present in their stomachs.”
– Milk is also definitely not a substitute for water. Milk is power food and the additional calories from drinking a lot of it on a regular basis can contribute to being overweight.
Milk is less of a beverage and more like a food, since it adds calories to our diet.
#The risk of child and adolescent overweight is related to types of food consumed, 2011
https://www.ncbi.nlm.nih.gov/pubmed/21702912
Quote: “The frequency of consumption of grains, nuts, vegetables and LNDF were inversely related to the risk of being overweight and dairy increased the risk.”
Still milk contains milk protein, which has a satiating effect. So in another context, milk can also contribute to weight loss.
#Effect of dairy consumption on weight and body composition in adults: a systematic review and meta-analysis of randomized controlled clinical trials, 2012
https://www.ncbi.nlm.nih.gov/pubmed/22249225
Quote: “Increased dairy consumption without energy restriction might not lead to a significant change in weight or body composition; whereas inclusion of dairy products in energy-restricted weight loss diets significantly affects weight, body fat mass, lean mass and WC compared with that in the usual weight loss diets.”
Dairy consumption and overweight and obesity: a systematic review of prospective cohort studies, 2011
https://www.ncbi.nlm.nih.gov/pubmed/21521450
Quote: “A range of dairy food exposure measures were used. Eight studies […] showed a protective association against increasing weight gain […]; one reported a significant protective association only among men who were initially overweight; seven reported no effect; one reported an increased risk (among children), and two reported both a decreased and increased risk, depending on the dairy food type.”
So overall, milk products are neither good nor bad and it’s not possible to claim that they generally promote or reduce obesity. Dairy can be part of a well balanced diet, but replacing all water with milk is not a good idea.
– Especially flavored milk or chocolate milk is more comparable to beverages like lemonade than a healthy snack.
Well, milk at least contains more nutrients than lemonade. And a lot less sugar (listed here as “Kohlenhydrate” = carbohydrates).
– About 33% of cropland is used to feed grazing animals, including dairy cattle.
#Livestock and Landscape,
http://www.fao.org/3/ar591e/ar591e.pdf
Quote: “33 percent of croplands are used for livestock feed production.”
– Dairy production is still responsible for 3% of all greenhouse gas emissions, even more thann all airplanes combined.
The complete livestock sector contributes 14.5% of the annual CO2 emissions. The milk production represents about 20% of these 14.5% and therefore 2.9% of the global emissions.
#Food Emissions: Direct agricultural emissions
https://ccafs.cgiar.org/bigfacts/#theme=food-emissions&subtheme=direct-agriculture
Quote: “Production of beef and cattle milk accounts for the majority of emissions, contributing 41% and 20%, respectively, of the sector’s emissions.”
In comparison: cement production only contributes 4-8% of the annual global CO2 emissions.
If you want to get a more detailed picture on human Greenhouse-Gas-emissions, we’ve gathered a couple of good sources right here:
#Global Greenhouse Gas Emissions Data,
https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data
#Tackling climate change through livestock: a global assessment of emissions and mitigation opportunities, 2013
http://www.fao.org/3/a-i3437e.pdf
#Report on milk health effects: milk and dairy products in human nutrition, 2013
http://www.fao.org/3/i3396e/i3396e.pdf
– Cows are impregnated over and over, separated from their young shortly after birth and slaughtered once their tortured bodies are not productive anymore.
We are aware that this is a sensible topic, so a general comment first: The practice of impregnating cows repeatedly, separating them from their calves and slaughtering dairy cattle once it has reached its peak is a fact and standard practice in dairy farming.
See this paper for reference:
# American and German attitudes towards cow-calf separation on dairy farms. PLoS One. 2017
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5354428/#\_\_ffn\_sectitle
Quote: „Separating the calf from the cow shortly after birth is a routine practice on dairy farms around the world. In brief, calves are separated from their dams within a few hours following birth and then housed in a separate location and fed artificially (with milk or milk replacer). Advocates of this practice argue that it prevents cow and calf from forming a strong bond, and thus reduces the stress associated with separation when it does occur. The results from a series of studies on the short-term acute affects support this claim“
It is questionable however if this practice can really be considered animal-friendly. The fact that cow and calf are separated at all is considered cruel and practically torture in the sense of inflicting psychological/ emotional pain especially by animal rights organizations and advocates for veganism.
#Treatment of cows in the dairy industry, 2018
https://proveg.com/5-pros/animals/cows/
#No Milk Today – Let's talk about Cows, 2012
There are also studies on common dairy farming practices and their effect on animals that found the separation to cause long-term stress:
#Invited review: A systematic review of the effects of prolonged cow–calf contact on behavior, welfare, and productivity, Journal of Dairy Science, 2019
https://www.sciencedirect.com/science/article/pii/S0022030219304369
Quote: „Separation of calves from cows within hours or days of birth is common on dairy farms. (…)Early separation (within 24 h postpartum) was found to reduce acute distress responses of cows and calves. However, longer cow–calf contact typically had positive longer-term effects on calves, promoting more normal social behavior, reducing abnormal behavior, and sometimes reducing responses to stressors.“
Of course there are regulations on farming practices and many farmers are doing their best to ensure the wellbeing of their livestock. The opinions on what exactly that means differ a lot though.
We looked at reports and websites from and for commercial dairy farmers and found this blogpost for example. It discusses the considerations of the industry for ensuring animal welfare in the dairy industry:
#Animal Welfare in Dairy System Design, 2019
https://www.dairyherd.com/article/animal-welfare-dairy-system-design
Quote:
„Instead of looking for what we do wrong in the dairy industry maybe we should look at what we do right. The “Five Freedoms of Animal Welfare” are as follows:
1. Freedom from hunger or thirst by ready access to fresh water and a diet to maintain full health and vigor.
2. Freedom from discomfort by providing an appropriate environment including shelter and a comfortable resting area.
3. Freedom from pain, injury or disease by prevention or rapid diagnosis and treatment.
4. Freedom to express (most) normal behavior by providing sufficient space, proper facilities and company of the animal's own kind.
5. Freedom from fear and distress by ensuring conditions and treatment which avoid mental suffering.
Freedom from hunger and thirst means providing 3+ inches per cow of waterer space, feed space of 30 inches for prefresh cows, 20+ hours per day of access to feed and water, and minimizing total milking time per day to less than 3 hours.(…)Freedom from fear and distress may be the hardest to measure and really know if we are doing our best. I think as an industry we are moving in the right direction with management tools like pain medication at dehorning, stockmanship training for employees, and protocols for downed cows.“
One could argue that it is up for discussion how animal-friendly and sufficient these considerations are. It is reassuring that such guidelines and concerns exist, but we also feel it is justified to question if they are enough.
In Germany for example the Ministry of Food and Agriculture is working on a project to monitor animal welfare in livestock farming; since this is a controversial topic especially in the public eye and an unmet need for more transparency has been identified.
#National Animal Welfare Monitoring
https://www.thuenen.de/en/cross-institutional-projects/national-animal-welfare-monitoring/
We are also aware that not all farms are the same – there is a wide range of systems, practices and standards globally and to condemn each and every dairy farmer would be unfair. But overall, intensive dairy farming/factory farming has increased significantly in the last few decades. Since intensive dairy farm is the practice most strongly associated with reduced or overall low animal welfare, this trend needs to be watched closely .
#Dairy intensification: Drivers, impacts and alternatives, 2019
https://link.springer.com/article/10.1007/s13280-019-01177-y
Quote: „It is possible to have high and low animal welfare in all production systems, including in those defined as extensive, organic or intensive. However, in very intensive confined feeding operations there are arguably limits to how ‘good’ welfare can be (Webster 1994). Rapid intensification in the dairy sector can have considerable impacts on animals’ physical and mental well-being, particularly in high-income countries, where measures to improve productivity deliver only moderate gains, often at the expense of animal welfare (Haskell et al. 2006; LeBlanc et al. 2006). In intensive operations, cows often lack freedom to perform natural behaviours of grazing, reproducing, and socializing in pasture but instead live in housing regimes that constrain movement and that require animals to stand on concrete floors for extended periods of time (von Keyserlingk et al. 2009). Intensive dairy systems have been shown to have a higher prevalence of lameness and other disease“
– In terms of protein levels and nutritional value only soy milk can compare to cow milk, the others need to be artificially enriched to reach similar levels of vitamins and calcium.
#How well do plant based alternatives fare nutritionally compared to cow’s milk?, 2017
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5756203/
Quote: “But, among alternative milks only soy milk contains comparable amounts of nutrients.”
– And another option might be available soon: several startups have created non-animal milk that is nutritionally identical to dairy milk
#Perfect day foodsTM, 2019
https://www.perfectdayfoods.com/
Summary:
#Got Impossible Milk? The Quest for Lab-Made Dairy, 2019
https://www.nytimes.com/2019/08/02/science/lab-grown-milk.html
– Many milk alternatives use significantly less energy, land and less water to produce.
Rice milk is a different story though. It produces a lot of methane, which isn’t always included in the numbers regarding emissions. So reports about that can be a bit misleading.
#Climate change: Which vegan milk is best?, 2019
https://www.bbc.com/news/science-environment-46654042
Cited study:
#Reducing food’s environmental impacts through producers and consumers, 2018
https://science.sciencemag.org/content/360/6392/987
FAQs:
Here we gathered all the topics that might pop up in arguments around milk, but would have stretched our video to an enormous length. We covered claims like pus in milk, hormone levels and more.
Q: How much resources does a liter of milk consume?
A: On average the production of a single liter of cow’s milk creates roughly 3.2 kg of greenhouse gas emissions, uses 628 liters of water and occupies about 9 sq m of land. These numbers can vary though, depending on which method of rearing is used and where the production site is located.
#Reducing food’s environmental impacts through producers and consumers, 2018
https://science.sciencemag.org/content/360/6392/987
#Climate change: Which vegan milk is best?, 2019
https://www.bbc.com/news/science-environment-46654042
#Mitigation of greenhouse gas emissions in European conventional and organic dairy farming, 2006
https://www.sciencedirect.com/science/article/abs/pii/S0167880905004214
#Effect of production system and farming strategy on greenhouse gas emissions from commercial dairy farms in a life cycle approach, 2011
https://www.sciencedirect.com/science/article/abs/pii/S1871141311000850
Q: Is the A1-beta-Casein from so called A1 milk bad for me?
A: In some studies, A1-beta-Casein has been associated with diabetes, gut diseases, neurological diseases and muscle damage...
#Ischaemic heart disease, Type 1 diabetes, and cow milk A1 β-casein, 2003
https://researchspace.auckland.ac.nz/handle/2292/4746
#A1 beta-casein milk protein and other environmental pre-disposing factors for type 1 diabetes, 2017
https://www.nature.com/articles/nutd201716
#Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cows’ milk, 2016
https://nutritionj.biomedcentral.com/articles/10.1186/s12937-016-0147-z
#Review on bovine beta-casein (A1, A2) gene polymorphism and their potentially hazardous on human health, 2014
#Study on allergy prevention by raw milk: Farm living: effects on childhood asthma and allergy, 2010
https://www.ncbi.nlm.nih.gov/pubmed/21060319
A: ...but meta analysis could not find any evidence for this.
#The A2 milk case: a critical review, 2005
https://www.nature.com/articles/1602104
#A1 vs. A2 Milk — Does It Matter?, 2019
https://www.healthline.com/nutrition/a1-vs-a2-milk
Q: Are there any pesticides in milk?
A: Well, residues of pesticides and antibiotics can end up in the milk via the fodder, dust or because some single farmers didn’t apply antibiotics correctly. Many countries like the members of the EU and the USA therefore set so called MRLs, Maximum Residue Limits. They state which and how much of these substances are allowed in milk.
EU
#Regulation (EC) No 396/2005 of the European Parliament and of the Council of 23 February 2005 on maximum residue levels of pesticides in or on food and feed of plant and animal origin and amending Council Directive 91/414/EEC (Text with EEA relevance)Text with EEA relevance, 2019
https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02005R0396-20190813
EU: Usually concentrations between 0,001 and 1,5 (group of substances collectively) mg/kg depending on substance, with 0,01 being the most frequent limit
USA:
#Report of the 51st session of the codex committee on pesticide residues, 2019
Residue levels for milk: 0.001 - 0.5 mg/kg, depending on substance
A: There are always black sheep in the flock and violations to those limits occur, but they are very rare.
EU:
Between 1 and 2%
#The 2016 European Union report on pesticide residues in food, 2018
https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2018.5348#efs25348-fig-0032
Residue levels over MRL in 1.8% of the cattle milk, 7 samples of 389
#The 2017 European Union report on pesticide residues in food, 2019
https://efsa.onlinelibrary.wiley.com/doi/full/10.2903/j.efsa.2019.5743
Residue levels over MRL in 1% of the milk, 1 sample of 103
residue levels over MRL cattle milk 23 samples
USA:
0%
#Pesticide Residue Monitoring Program Fiscal Year 2017 Pesticide Report, 2017
https://www.fda.gov/media/130291/download
0% violations for milk
#Pesticide Residue Monitoring Program Fiscal Year 2016 Pesticide Report
https://www.fda.gov/media/117088/download
0% violations for milk
Q: What about antibiotics?
A: For them it’s quite the same as for pesticides. There are Limits, which can’t be violated, otherwise the milk must be destroyed to avoid fostering antibiotic resistances in bacteria. We covered this topic in a separate video.
#Commission Regulation (EU) No 37/2010 of 22 December 2009 on pharmacologically active substances and their classification regarding maximum residue limits in foodstuffs of animal origin (Text with EEA relevance), 2019
https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1574428837207&uri=CELEX:02010R0037-20190303
List of medically active substances allowed / prohibited in the EU
Mostly two and three digit microgram amounts (= a millionth gram), or forbidden all together
#National Drug Residue Milk Monitoring Program, 1997, 2017
https://www.fda.gov/food/food-compliance-programs/national-drug-residue-milk-monitoring-program
List of tolerance levels in ppb (parts per billion)
Q: How often are Antibiotic limits violated?
A: Not often. The amount of samples which cross the limits usually don’t cross the 1% threshold. Of course every positive sample is one too much but it is still reassuring that violations are rare.
Europe:
#Report on the implementation of national residue monitoring plans in the member states in 2015
https://ec.europa.eu/food/sites/food/files/safety/docs/cs_vet-med-residues_workdoc_2015_en.pdf
Number of targeted samples analysed and percentage of non-compliant samples for antibacterials (B1) in animal/product categories = 0.08%
#Report on the implementation of national residue monitoring plans in the member states in 2016
https://ec.europa.eu/food/sites/food/files/safety/docs/cs_vet-med-residues_workdoc_2016_en.pdf
Percentage of non-compliant samples for antibacterials (B1) in animal/product categories = 0.06%
#Report for 2017 on the results from the monitoring of veterinary medicinal product residues and other substances in live animals and animal products, 2017
https://ec.europa.eu/food/sites/food/files/safety/docs/cs_vet-med-residues_workdoc_2017_en.pdf
Percentage of non-compliant samples for antibacterials (B1) in animal/product categories = 0.18%
USA:
0,78% = 15 of 1912 analyzed
#Milk drug residue sampling survey, 2015
https://www.fda.gov/media/91217/download
Q: What about hormone levels?
A: This is a complex topic that we mentioned only shortly in the video. Usually there is a natural amount of hormones in milk. But the concentration is so low that it’s far under the concentrations we humans produce ourselves. And since milk is digested, most of the hormones are destroyed in our liver.
#Questions and Answers on Hormones in Meat and Milk, 2014
https://www.bfr.bund.de/en/questions_and_answers_on_hormones_in_meat_and_milk-191516.html
Quote:
“Furthermore, the hormones are metabolised very quickly (pronounced “first pass” effect of the liver with peroral intake). The available scientific data do not currently give any reason to assume any relevant health risk.”
Q: What are normal hormone limits?
To put this in perspective: the values here are given in nanogramm. This is the billionth of a gram.
#Questions and Answers on Hormones in Meat and Milk, 2014
https://www.bfr.bund.de/en/questions_and_answers_on_hormones_in_meat_and_milk-191516.html
Quote: “The natural estrogens include estrone and in particular estradiol as important representatives of this group. In full-fat milk (fat content 3.5%), total concentrations are given as 0.13 micrograms of estrone and less than 0.02 micrograms of estradiol per kilogram of milk.”
A: A study looked at how much more hormones we would have to take to influence our hormone system. The result was carried out in mice and concluded, that we would need the 1.000 fold concentration you would normally find in milk.
#Consumption of Natural Estrogens in Cow’s Milk Does Not Affect Blood Levels or Reproductive Health, 2016
Until effective, people would have to take in the 1,000 times concentration of hormones, which occur in milk naturally.
Q: Is calcium connected to osteoporosis?
A: One argument claims that milk would even break calcium out of the bones. This can’t be confirmed. Milk indeed does contribute to a healthy calcium intake. This also contradicts the statement milk would cause osteoporosis.
#Dairy product intake in children and adolescents in developed countries: trends, nutritional contribution, and a review of association with health outcomes, 2014
https://www.ncbi.nlm.nih.gov/pubmed/24330063/
#Osteoporosis: Is milk a kindness or a curse?, 2017
https://www.ncbi.nlm.nih.gov/pubmed/27726930
Q: Are fermented milk products healthier?
A: It’s hard to give a definite answer here. Studies suggested a weak correlation between fermented milk products and sugar regulation, which could be beneficial for avoiding Type II diabetes. But since some studies are partly based on self report or only found tiny differences, these results have to be treated with care.
#Dairy product intake in relation to glucose regulation indices and risk of type 2 diabetes, 2013
https://www.sciencedirect.com/science/article/abs/pii/S0939475312001536
#Consumption of dairy products and associations with incident diabetes, CHD and mortality in the Whitehall II study, 2013
A: Same goes for fermented milk products and stroke. Fermented milk like cheese and a few other dairy products seem to reduce the risk of stroke, while other milk products like butter and cream don’t. Interestingly also the amount of the intake seems to play a role. So more investigation is needed before we can proudly say, cheese stops strokes.
#Dairy foods and risk of stroke: A meta-analysis of prospective cohort studies, 2014
https://www.sciencedirect.com/science/article/abs/pii/S0939475313003116
#Dairy Consumption and Risk of Stroke: A Systematic Review and Updated Dose–Response Meta‐Analysis of Prospective Cohort Studies, 2016
https://www.ahajournals.org/doi/full/10.1161/jaha.115.002787
Q: Is there pus or blood in my milk?
A: Immune cells, which are responsible for the production of pus, naturally occur in milk and are completely normal. But they can turn into pus, if the cow suffers from a so called mastitis, an infection of the udder. This can also cause the blood in the milk. Whenever milk with blood or pus in it appears, it is gathered separately and discarded.
#A comparative study on the blood and milk cell counts of healthy, subclinical, and clinical mastitis Karan Fries cows, 2015
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4774734/
Q: Does milk cause inflammation?
A: This is not proven. Inflammations are usually too complex to be triggered by a food. In a meta-study from 2017, even the opposite was observed. So milk causes no inflammation, unless you are allergic to it, but in that case you should avoid milk products anyway.
#Dairy products and inflammation: A review of the clinical evidence, 2017.
https://www.ncbi.nlm.nih.gov/pubmed/26287637
#Consumption of sucrose-sweetened soft drinks increases plasma levels of uric acid in overweight and obese subjects: a 6-month randomised controlled trial, 2015
https://www.ncbi.nlm.nih.gov/pubmed/26081486
Q: Is milk bad for my cholesterol level?
A: There is cholesterol in milk, but our bodies are incredible systems, which can adapt to our intake of this substance as long as we don’t go overboard. A reasonable intake of dairy products does not alter the cholesterol level in a negative way.
#Milk and Dairy Product Consumption and Cardiovascular Diseases: An Overview of Systematic Reviews and Meta-Analyses, 2019
https://academic.oup.com/advances/article-abstract/10/suppl_2/S164/5489436?redirectedFrom=fulltext
Quote: "Therefore, the present study states that the consumption of total dairy products, with either regular or low fat content, does not adversely affect the risk of CVD."
#Increasing Selenium and Vitamin E in Dairy Cow Milk Improves the Quality of the Milk as Food for Children, 2019
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6627237/
No child surpassed critical cholesterol values, even though milk elevated them.
Q: Does milk hydrate better than water?
A: This is actually true. Due to its composition, milk acts like an isotonic beverage. But as we stated in the video, it also adds calories to our diet. So completely replacing water with milk is still not the best idea.
#A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index, 2015
https://academic.oup.com/ajcn/article/103/3/717/4564598
Further reading:
– Milk controversies over the decades.
#The Surprisingly Intolerant History of Milk, 2018
https://www.smithsonianmag.com/history/surprisingly-intolerant-history-milk-180969056/