Scientists from the Allergy Group in the department of nutrition and health at the Nestlé Research Center in Lausanne stress that the effects are currently limited to mice. “It will now be important to study whether these mechanistic findings apply to humans too. To this end, a safety study in allergic children has been initiated,” they state in Clinical & Experimental Allergy.
If the results can be repeated in humans, the apple polyphenols may offer hope for the increasing number of people suffering from allergic disease. An estimated eight per cent of children in the EU suffering from food allergies, according to the European Federation of Allergy and Airways Diseases Patients' Associations.
The most common food allergen ingredients and their derivatives are cereals containing gluten, fish, crustaceans, egg, peanut, soybeans, milk and dairy products including lactose, nuts, celery, mustard, sesame seed, and sulphites.
An apple a day…
The Nestlé researchers built on previous findings that apples have been report to reduce certain allergies, like respiratory allergy and atopic dermatitis.
Mice that displayed an allergy to ovalbumin, a protein in egg white, were fed a polyphenol-rich extract from apple (Pomactiv HFV, from Val de Vire Bioactives, France) either during the ovalbumin challenge, or just before, and their immune response was measured.
Data showed that the apple polyphenols did indeed reduce the allergic response to the ovalbumin in the mice, but only when consumed before the challenge: No effects were observed if consumed during the ovalbumin challenge, said the researchers.
Commenting on the potential mechanism, Dr Annick Mercenier and her co-workers indicated that at least two mechanisms may be occurring. The polyphenols may be reducing the release of an allergic mediator by cells called effector cells, which are white blood cells activated by the presence of an allergen.
A second mechanism may involve a binding of the apple polyphenols to the allergen itself, which would reduce the allergenicity of the protein. Indeed, other studies have shown that polyphenols may change the structure of an allergen, “which resulted in a strong reduction of the IgE-binding capacity of this allergen”, wrote Dr Mercenier and her co-workers.
Source: Clinical & Experimental Allergy
June 2010, Volume 40, Issue 6, Pages: 942-950
“Polyphenol-enriched apple extract attenuates food allergy in mice”
Authors: A. W. Zuercher, S. Holvoet, M. Weiss, A. Mercenier