How many people are affected by food allergy?
This is a question that is very difficult to answer because different studies provide different results due to the diversity in study designs. A recent review showed most studies found that clinically proven allergy to any food occurs in 1-5% of the total population.
Recently researchers in the EU-funded EuroPrevall project looked at more than 900 published studies to access the percentage of people with food allergy in the community. The researchers found that if surveys asked people if they think they have food allergies, 3 - 38% answered yes, although only few studies had figures above 20%. However, only 1 - 11% of these people had their food allergy confirmed by a medical specialist. Most of the studies in which food allergy was clinically proven reported that 1-5 % of the total population had any food allergy. So there is a large gap between the number of people who think they have a food allergy and the number of people who are diagnosed as allergic.
Many people believe that the number of people with food allergy is increasing. It is also an impression gained by the doctors running allergy clinics that the occurrence of food allergies changes with age and varies across different geographical areas. However, we generally lack research results that can clarify whether this is in fact true.
Children and food allergy
It is an impression gained by allergy doctors that milk and egg allergies are among the most common kinds of food allergy in children. At the age of 3-5 years many of the children with milk and egg allergy have outgrown their allergy. Other foods frequently causing allergic reactions in older children are peanut, fish, and tree nuts. These allergies will often last for a lifetime.
Adults and food allergy
Clinical evidence suggests that fruits, vegetables, tree nuts, and peanuts are responsible for most allergic reactions among adults. Most of the allergic reactions among adults start because of cross-reactions resulting from allergies to pollen or latex. People who are allergic towards pollen or latex may experience problems when eating certain fruits, vegetables, and nuts. This is because our bodies cannot distinguish between the allergens in pollen or latex and similar proteins in foods.
The occurrence of food allergy probably varies across different geographical areas e.g. because of different dietary patterns and differences in exposure to pollen. For instance fish allergy appears to be more common in countries like Norway, Portugal and Japan where fish is consumed in greater amounts than in most other countries. Another example is hazelnut allergy, which appears to be more common in geographical areas where birch pollen is abundant because of cross-reactivity between the birch pollen and hazelnut.
Little information exists on gender differences in food allergy in children. In adults, an impression gained by allergy doctors is that food allergy is more common in women. However, it is not known whether this gender difference is due to physiological differences or to differences in health-seeking behaviour between men and women.
EuroPrevall state of the art papers:
- R.J. Rona, T. Keil, C. Summers, D. Gislason, L. Zuidmeer, E. Sodergren, S.T. Sigurdardottir, T. Lindner, K. Goldhahn, J. Dahlstrom, D. McBride, C Madsen (2007). The prevalence of food allergy: A meta-analysis. J Allergy Clin Immunol 120(3), 638-646.
- L. Zuidmeer, K. Goldhahn, R.J. Rona, D. Gislason, C Madsen, C. Summers, E. Sodergren, J. Dahlstrom, T. Lindner, S.T. Sigurdardottir, D. McBride, T. Keil (2008). The prevalence of plant food allergies: a systematic review. J Allergy Clin Immunol 121, 1210-1218.
Lay version of the above papers:
General chapter on epidemiology of food allergy and specific frequency data for cereals, crustaceans, fish, eggs, peanuts, soy, milk, nuts, celery, mustard, sesame, and sulphites:
Prevalence of all allergens, milk, egg, peanut, tree nuts, fish shellfish, and soy in the United States: