Proponents of the "hygiene hypothesis" assert that early exposure to bacteria and other microbes promotes the healthy development of a child's immune system and that weakened immunity rather than exposure to germs causes children to succumb to illnesses.
Cleanliness May Cause More Harm Than Good
Increasingly sterile homes and other human environments minimize people's exposure to disease-causing pathogens including bacteria, viruses, fungi, and parasites, as well as potential allergens including dust, pollen, and mold.
Antibacterial soaps, as well as vaccinations and antibiotics, may inhibit healthy immune development. For example, children who contract diseases such as chicken pox or measles develop lifetime immunity to those diseases, whereas children who receive vaccinations require booster shots for continued immunity. Alternative vaccination schedules may minimize risks associated with vaccines.
A study published by the Journal of the American Medical Association found that children who had early exposure to pets and livestock were less likely to develop allergy-related diseases later in life, suggesting that early exposure to potential allergens bolstered the children's immune systems against those substances [Platts-Mills. Paradoxical Effect of Domestic Animals on Asthma and Allergic Sensitization. JAMA, 2002].
The JAMA study also found that children in large families suffered fewer illnesses than children in smaller families, suggesting that larger families exposed children to more germs, which increased their immunity to common infections.
Factors in Healthy Immune Function
A Juvenile Diabetes Research Foundation study found that susceptibility to type 1 diabetes and other autoimmune disorders may result from lack of exposure to certain parasites and microbes. In the study, mice raised in a germ-free environment developed diabetes while mice exposed to common intestinal bacteria remained resistant to developing the disease [JDRF Funded Study Links Hygiene Hypothesis to Diabetes Prevention. Nature Magazine, 2008].
Practices to support or boost healthy immune function and development, include breastfeeding and a diet rich in fruits, vegetables, fermented foods, and omega-3 fatty acids, and low in sugar, carbohydrates, and chemical additives.
The University of Helsinki will conduct the DIABIMMUNE research project during the years 2008-2013 to test the hygiene hypothesis and establish if the decrease in a person's infection load contributes to the development of type 1 diabetes and allergies.
The DIABIMMUNE project was conceived to address the question of why Finnish children develop type 1 diabetes and allergic symptoms approximately five times more often than Russian Karelian children with similar genetic factors that predispose them to autoimmune disease.
Even when they are exposed to germs and allergens, a strong immune system can prevent children from getting sick. Some scientists believe that exposure to germs boosts the immune system's disease-fighting ability and protects people from developing disease. If this proves true, getting dirty may help children stay healthy.
Sara McGrath - Sara is a veteran homeschool mom of three, Usborne consultant, and the author of Unschooling: A Lifestyle of Learning.
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