Nutrition
Diet therapies or nutritional advice is the most common integrative approach for asthma. Changes in the diet and/or supplementation are meant to alter immune response and therefore airway reactivity. Strong epidemiologic data demonstrates an association between dietary deficiencies (omega-3, vitamin C, magnesium, selenium, Vitamin E) and asthma. Conversely, populations with higher intake of pro-inflammatory polyunsaturated fatty acids (omega-6 fatty acids) have a higher prevalence of asthma, eczema, and allergic rhinitis.
It is thought that eliminating certain "allergenic" type foods and decreasing exposure to items such as dairy products (believed to be associated with increased mucus production) will help with chronic asthma symptoms and their severity. The data to support such approaches are mixed.
Nutritional considerations include (on this page):
Epidemiology
General Strategy
Vegan Diet
Elimination Diet
Weight Loss
Breast Feeding
Epidemiology
Diet therapies or nutritional advice is the most common integrative approach for asthma. Changes in the diet and/or supplementation are meant to alter immune response and therefore airway reactivity. Strong epidemiologic data demonstrates an association between dietary deficiencies (omega-3, vitamin C, magnesium, selenium, Vitamin E) and asthma. Conversely, populations with higher intake of pro-inflammatory polyunsaturated fatty acids (omega-6 fatty acids) have a higher prevalence of asthma, eczema, and allergic rhinitis.
It is thought that eliminating certain "allergenic" type foods and decreasing exposure to items such as dairy products (believed to be associated with increased mucus production) will help with chronic asthma symptoms and their severity. The data to support such approaches are mixed. Nutritional considerations include:
General Strategy
It is worthwhile to manage the diet of the asthma patient. Often times, hidden food triggers, obesity and nutrient deficiencies play a role in the severity of symptoms. The following general guidelines will be helpful:
1) Eliminate potential allergens
Sulfites (especially in dried fruits).
Food additives (aspartame, benzoates, and yellow dye #5).
Wheat and dairy products (for a trial period, as mentioned previously).
2) Increase intake of fruits and vegetables, because they are rich in antioxidants
3) Increase intake of omega-3 fatty acid intake by eating cold-water fish (e.g., sardines, herring, and salmon)
4) Reduce intake of omega-6 fatty acids by eliminating vegetable oils and instead using olive oil
5) Set appropriate BMI targets if overweight
6) Encourage breast feeding when appropriate, especially in patients with strong family history of atopy
Vegan Diet
Few studies have been conducted on whole diet interventions. One positive long-term study of vegan diet was published in 1985 by Lindahl. Vegan diets are vegetarian diets that also eliminate eggs, fish, and typically processed foods high in refined sugars, preservatives and other chemicals. The Lindahl study was characterized by:
One-year prospective study, 25 subjects
Diet excluded meat, fish, eggs, dairy, coffee, tea, chocolate, sugar, and salt
Decreased cost and use of medications
92% improvement in biochemical and clinical markers
Some patients are reluctant to remove the above-mentioned foods from their diet. Nonetheless, if a patient is willing, it has been found by the author that symptoms can improve in six to eight weeks after removal of the offending agent(s). Some patients decide to make this a lifestyle choice should their asthma symptoms improve.
Elimination Diet
Elimination diets are designed to identify and remove food triggers to improve symptoms. While elimination diets have not been well studied in asthma, they have shown some clinical utility in other diseases such as rheumatoid arthritis.
To have a patient undergo an elimination diet have them pick a food that they appear to be sensitive to and eliminate it from the diet for two weeks. At the end of two weeks, reintroduce the food into the diet.
If there is a significant change, such as increased wheezing or coughing, the patient may indeed be sensitive to that particular food. If no change in symptoms occur, select another food, and repeat the approach.
Common food triggers to select are:
Wheat
Dairy
Corn
Sugar
Peanuts and Tree Nuts
Eggs
Food additives and preservatives
Weight Loss
Fat cells are pro-inflammatory. They secrete cytokines and immune proteins that can contribute to an inflammatory state such as asthma. It has been shown that when asthmatics lose weight, their symptoms improve.
For example, Stenius-Aaniala (2000) demonstrated that weight loss in obese subjects with asthma:
14.5% weight loss improves FEV1 and FVC
Reduced medication use, exacerbations, and dyspnea
Improvement persisted for over one year
For those patients who are overweight, it is important to provide general counseling on healthy BMI and encourage weight loss when indicated.
Breast Feeding
Breast feeding has been shown to reduce the development of atopic diseases. Immunoglobulins in breast milk favorably affect the balance of TH1/Th2 reactions along the gut mucosa and also helps to mature intestinal flora.
In a meta-analysis of 800 subjects (Gdalevich 2001), it was shown that breast feeding during the first three months of life reduced likelihood of developing asthma by 30-50%. The beneficial effects were most pronounced in children with a family history of atopy.
While administration of probiotics have been studied in children with allergies, with potentially favorable results, no such studies exist in the asthma population. Despite this, it is common practice for integrative providers to recommend probiotics early in life in an attempt to influence bacterial populations in the digestive tract in order to alter immune function in children with a family history of atopic disease.