Theories Vary On Why Food Allergy Cases Are Increasing
By Joel S. Klein, M.D., Advocate Lutheran General Hospital/Advocate Lutheran General Children's Hospital
One of the pleasures of life is enjoying the taste, texture and smell of food. But, for some of us, one or more foods is an allergy and can have life-threatening effects because of the human body's immune system.
Food allergy is different than food intolerance. A food intolerance, such as lactose intolerance or drinking too much coffee, does not occur because the food activates the immune system. Food allergy happens because the immune system recognizes the food as foreign to the body. While at least 20 percent of us change our diet because of reactions to foods, food allergy affects about 5 percent of young children and 3 percent to 4 percent of adults in Westernized countries.
The number of people with food allergies has increased. Many middle-aged adults, such as myself, and older adults don't recall any classmates with food allergies while growing up. Some children with a food allergy have no family history of it. The CDC has reported an 18 percent increase in childhood food allergy from 1997 to 2007.
The reason for this increase isn't clear. But there are many theories, which stem from the focus on peanut allergy. One theory, known as the hygiene hypothesis, is that trying to avoid an infection or overtreating an infection during the first one to two years of life prevents the immune system from developing certain processes that would not reject the food.
Other theories include: imbalances of antioxidants, fats or nutrients; the use of antacids that keep the food protein intact longer; and food processing – for example, roasting, instead of boiling, a peanut makes an allergic reaction more likely.
Areas about food allergies need further study, such as:
- Factors, in addition to asthma, which cause a higher risk for serious consequences from a food allergy.
- Additional reliable laboratory tests when the results of skin tests and the blood antibody test do not confirm a suspected cause.
- Whether breast-feeding beyond 6 months of age prevents food allergy and other allergic conditions.
- Whether restricting a mother's diet during pregnancy or during breast-feeding prevents food allergies from developing.
- A safe and effective preventative therapy, so one would not have to avoid eating the food that causes symptoms.
Trained health care professionals know how to diagnose a food allergy, make reasonable judgments on which foods to avoid, how to avoid them and how to treat reactions that occur. Those who are considered at risk for life-threatening reactions should carry an epinephrine (adrenaline) auto-injector device that can quickly stop a serious reaction.
Food allergy is manageable. It takes education about what could contaminate a meal with a food allergen when cooking in the kitchen. It takes vigilance to read labels on food containers to be sure the food allergen is absent. And patience, as with any situation, is needed with those who need to learn about food allergy.
Some resources for more information about food allergy include the following web sites: