Atopy Dermatitis

An atopic disease is a form of allergy where the hypersensitivity reaction occurs at a location different from the initial contact point between the body and the offending agent (allergen). For example, food taken by mouth may cause an allergic skin reaction - atopic dermatitis. The incidence of atopic diseases such as dermatitis, allergic rhinitis, and asthma is rising in industrialized countries and now affects about 20% of the population.

A team of researchers from the University of Turku and Tufts University in Boston now report that the increase in atopic diseases is closely tied in with an increase in the consumption of omega-6 fatty acids (linoleic acid) which have pushed the ratio of omega-6 to omega-3 (alpha-linolenic, eicosapentaenoic, and docosahexaenoic acids) fatty acids in the diet to an unfavorably high level (10:1 or higher). An increasing dietary intake of linoleic acid has been linked to a rise in atopic diseases in both Germany and Japan. A recent study of Finnish and Swedish school children found that children with a high ratio of eicosapentaenoic acid to linoleic acid had a lower prevalence of atopic diseases while children with allergies tended to have a lower level of docosahexaenoic acid in their blood.

The researchers point out that the metabolic products (Eicosanoids) of omega-6 fatty acids promote inflammation while the metabolites of omega-3 acids dampens inflammation. They also point to several clinical trials, which have shown that supplementation with fish oil, or alpha-linolenic acid can reduce the symptoms of atopic dermatitis and asthma. They conclude that an increased intake of omega-3 fatty acids (fish oils and alpha-linolenic acid) may alleviate atopic diseases caused by an excessive intake of omega-6 fatty acids.