Diet for asthma and eczema

by Sue Gilbert, MS

Q: I have a six-year-old daughter who suffers from asthma and eczema. I have heard about controlling these illnesses through diet. Is there a connection, and what foods might be helpful or harmful for her? Thank you for your time.

A: Diet can affect asthma in two ways. First, some foods can provoke asthma attacks by causing an allergic reaction. If you find that eating certain foods are closely followed by an asthma attack, then, as you probably know, those foods need to be eliminated from your daughter's diet in order to prevent such attacks. Some of the most common food-allergy asthma triggers are: eggs, nuts, milk, sulfites, fish and chocolate.
Diet can also affect asthma by helping to control the severity of an attack. Food can actually dilate air passageways, opening them up for freer breathing. One of the best-known foods for doing this is coffee, due to the caffeine, but you not want to offer coffee to your daughter, as caffeine can have other unwanted side effects. Food can also help by thinning the mucus so that it can move out of the airways, easing breathing.
There are even some foods that offer an immediate relief from an attack. The foods in this category include the spicy, pungent foods like chili, hot mustard, garlic and onions. It may be that these hot foods work by stimulating nerves, resulting in the release of watery fluid in the mouth, throat and lungs. This watery secretion will help to thin down the mucus so that it can more easily move out of the airways. Thirdly, some foods can control inflammation of the airways because they contain anti-inflammatory components in their chemical makeup. Foods that help to do this include onions (these are particularly good), fatty fish (fish oil is a proven anti-inflammatory high in omega 3 fatty acids) and vitamin C-packed foods.
Studies have also shown that a diet high in dairy and meat cause more asthma attacks than vegetarian diets. It may be that there are more allergenic components in dairy and meat. Vegetable oils high in omega-6 fatty acids should be avoided as it promotes inflammation. Oils high in omega-6 fatty acids include sunflower oil, corn oil and safflower oil.
Like asthma, a flare-up of eczema can be triggered by allergen-containing foods. Similarly, the way to prevent the flare-up is to avoid the food. In order to prevent unnecessary restriction of foods in your daughter's diet, it would be wise to consult with an allergist so that you can pinpoint the culprit. Unlike asthma, however, I cannot find evidence of diet affecting the treatment of eczema. It seems that more atopic cures must be used. In addition to avoiding the offending food, if that is the cause of your daughter's eczema, try to keep your daughter well-hydrated. This will help insure that her skin does not dry out and become flaky, compounding the eczema.
If you haven't already, I suggest that you visit The Food Allergy Network at http://foodallergy.org as they may have some helpful suggestions for you.
Thank you for writing. I hope that these dietary suggestions offer some relief to your daughter.