Have you heard of the hygiene hypothesis? I remember first learning about it in my undergrad immunology classes (my favorite!). It’s a topic that comes up again and again, because it’s so important to the future health of our children.
According to the hygiene hypothesis, a germ-free environment can lead to allergies and autoimmune diseases later on in children. Westernized lifestyles are linked to higher rates of allergy, asthma, eczema, and autoimmunity. The rate of these chronic diseases is increasing. In the United States alone, the prevalence of asthma increased 75% from 1980 to 1994. Scientists believe the change in asthma and allergy rates is due to our environment, not just genes. Genes do not evolve and change that quickly over time.
So what’s wrong with our environment then? Is it air pollution? Indoor exposure to allergens? Air quality can worsen asthma, however the air pollution has actually improved in areas where asthma has increased. Research has actually shown that family size matters more. A larger family means increased germs and infections. It turns out that fighting off childhood infections is likely protective for asthma. This link has also been found in children that attend daycare early on. They also found a link between growing up on a farm vs. in the city. The common thread here is thought to be germs (from other children or animals) Being exposed to more germs is linked to lower risk of allergies and asthma.
So, based on this, what can we actually do to prevent allergies and asthma in children? Moving onto a farm and having a dozen children is unlikely an option for many… But, here’s a few things you probably can do:
1. Don’t over-sanitize.
Meeting “friendly germs” helps the children’s young immune system learn. When the immune system is “bored”, is when allergies are more likely to develop. In fact, research has shown that children are less likely to have asthma or eczema if their parents “cleaned” the pacifier by sucking on it. So, let your child play in the dirt, both science & human history agree!
2. Let a fever run its course.
The young immune system is still learning, and children will get sick often. Unless the fever gets dangerously high, let the child’s immune system learn to fight the infection. However, if you have concerns, always see a healthcare provider.
3. Limit antibiotic use.
Antibiotics may be necessary — however, if not required, avoid them! Antibiotic use in the first year of life is associated with increased risk for asthma in young children (age 7 years). Here’s a reminder that antibiotics are not useful against viral infections (eg. influenza). See your naturopath for other ways to help fight childhood infections.
4. Eat organic.
Research shows that children fed organic diets have lower levels of pesticides in their urine. Environmental toxins can impair the developing immune system and increase the risk of allergies and asthma. If organic is not always possible, consider organic for the “dirty dozen” fruits and vegetables only.
5. Avoid second-hand smoke.
Tobacco is the main indoor air pollutant, and very preventable. Exposure to second-hand smoke directly, or indirectly during pregnancy, is related to asthma and allergies in children.
References
Hesselmar, B., Sjöberg, F., Saalman, R., Åberg, N., Adlerberth, I., & Wold, A. E. (2013). Pacifier cleaning practices and risk of allergy development. Pediatrics, 131(6), e1829-e1837.
Kozyrskyj, A. L., Ernst, P., & Becker, A. B. (2007). Increased risk of childhood asthma from antibiotic use in early life. Chest, 131(6), 1753-1759.
Wills-Karp, M., Santeliz, J., & Karp, C. L. (2001). The germless theory of allergic disease: revisiting the hygiene hypothesis. Nature Reviews Immunology, 1(1), 69.
Yang, S. N., Hsieh, C. C., Kuo, H. F., Lee, M. S., Huang, M. Y., Kuo, C. H., & Hung, C. H. (2014). The effects of environmental toxins on allergic inflammation. Allergy, asthma & immunology research, 6(6), 478-484.
