Review of antioxidants' role in allergic disease

Many researchers around the world have investigated the role of declining dietary antioxidant intake in the relatively recent increase in allergic disease. A paper published in the March 2010 issue of Clinical & Experimental Allergy looks at several studies in this area and reviews the information gained so far.

Studies using animal models have demonstrated that antioxidant supplementation at the time of primary and subsequent allergen exposure reduces allergic inflammatory responses; however data from human studies are less clear. Many human studies in this area predominantly focus on asthma, with results suggesting that single antioxidant supplements have little if any clinical benefit in adults. Many of these observational epidemiological studies of humans are also affected by methodological limitations associated with the assessment of diet.

A small number of birth cohort studies have reported potentially beneficial associations between maternal intake of some antioxidants during pregnancy and childhood asthma. As yet, there is very limited data suggesting potentially beneficial associations between maternal antioxidant intake and childhood atopic dermatitis and allergic rhinitis.

In concluding their review, the authors state the available epidemiological, animal, molecular and immunological data suggest that there are associations between antioxidants and asthma and to a much lesser extent, atopic dermatitis and allergic rhinitis, however the exact nature of the relationships and the potential for therapeutic intervention remain unclear.

Reference: Allan et al. 2010. Clinical & Experimental Allergy. Vol 40(3).pp 370-380.