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ABC's Of Allergies
(Released August 2006)

 
  by Sujata Suri  

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Reducing the Risk of Developing Allergic Diseases

Contents

While the exact cause of allergies is not clear, many scientists believe that genetic factors in the allergic person and environmental factors act together in their development. Numerous studies have reported an association between genes that exert their effects predominantly in combination with environmental factors, e.g., cigarette smoke (Kabesch, 2006) or tobacco smoke (Diaz-Sanchez, 2006), to cause allergies.

hand holding cigarette
Cigarette smoke is a common cause of allergies
At least some early life exposure to common household microbes and unpasteurized milk reduces our later risk of acquiring allergies. Allergic people can avoid triggering allergy symptoms by limiting the exposure to allergens. Healthy eating habits and exercise can further strengthen one's immune system and avert undesired effects.

Bacterial extracts have been reported as "modulators" of the host immune system. In one study farmer's children and rural residents were reported to be less likely to develop allergies than their urban counterparts. Perkin and Strachan (2006) proved that unpasteurized or raw milk consumption was associated with significantly lower IgE levels and fewer allergy symptoms. Several studies in human volunteers report that ingestion of probiotic bacteria (Lactobacillus, bifidobacterium, eubacteria) or fermented milk products or exposure to environmental mycobacteria are helpful in preventing allergies (Matricardi et.al, 2003; Schrezenmeier and Vresem, 2001; Adlerberth et al. 1991). These different bacteria have a role in modification of Th2 to Th1 immune response and induction of interferons (IFN-^g), interleukins (IL-2, IL-12) and allergen-specific IgG antibodies that antagonize IgE mediated effects. (Matricardi et.al, 2003).

Although allergens are known to increase symptoms in allergic individuals, early exposure to some of them, e.g., common environmental microbes as fungal spores or bacteria in mattresses, carpets, play grounds, unsanitary places, decreases the chances of developing an allergy. The exposure to bacterial endotoxins and lipopolysaccharides present in unpasteurized milk, yoghurt or fermented milk early in life helps prevent the development of asthma and other related allergies (Douwes et al. 2006). Similarly, the presence of an animal in the home has been associated with decreased sensitization to animal allergens.

Infections with helminthes in early life reduced the risk of developing allergies. Mangan et al. (2006) proved in their animal model studies that infection with parasitic worms like Schistosoma mansoni in mice reduced respiratory allergic disorders by increasing the production of interleukins (IL-4, IL-10 and IL-13) and reduction of IL-5 levels. If a person has little or no exposure to helminth infections in childhood, Th1 cells will not be stimulated to produce the cytokines and interferons that help prevent the overproduction of IgE which results in an increased risk of developing allergies (Bell, 2002).

Thus some exposure to microbes, helminths, and unpasteurized milk in early life can reduce the probability of developing allergies.

Go To Beware of the Common Allergens

Special thanks to Deborah Whitman for her invaluable help with this Discovery Guide

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