Apparently the squeaky-clean obsession is not just silly but unnecessary too: Dirt is good for us. When we get dirty, we expose our immune system to germs, which train it to develop and get stronger. Or so says the “hygiene hypothesis”, based on several scientific studies.
The idea is that people need to be exposed to a wide array of microorganisms in order to keep their immune systems alert and fighting fit. The hygiene hypothesis suggests that while avoiding germs can prevent infections, exposure to pollen, dust and microbes actually allows your immune system to fight back. It is much-needed target practice for your body (much like your building’s fire drill), and strengthens your immunity for future assaults that may be deadlier.
The pioneer of the hygiene hypothesis seems to be Mary Ruebush, a microbiology and immunology instructor at Kaplan Medical, US, and author of Why Dirt is Good: 5 Ways to Make Germs Your Friends. In her book, she says: “What a child is doing when he puts things in his mouth is allowing his immune response to explore his environment.” And Ruebush is not alone.
Should you believe this?
A September study by researchers at the University of Manchester, published in the Journal of Allergy and Clinical Immunology, found that children who attend day-care centres may be less likely to suffer from asthma and wheezing than their stay-at-home peers. This supports the hygiene hypothesis: Early exposure to infectious agents in day care or from older siblings (who are likely to contract infections from the outside world) offers protection.
The hygiene hypothesis is fairly new for Indian health experts, but it is already gaining supporters. Shubnum Singh, clinical allergist, Max Healthcare, seems to be in its favour: “I agree that a little dirt is good for you,” says Singh. “Your body can only build up antibodies if it has something to react to.”
She explains that we have killer and helper T-cells generated by the thymus gland to moderate our bodies’ immune responses “to steer our way through a sea of infections and allergens by producing adequate numbers of protective antibodies”.
If you live in a spick and span bubble, she says, the killer cells have essentially nothing to fight and end up fighting innocuous agents: pollen, foods or, worst, one’s own body (causing autoimmunity disorders). “As time passes, if not stimulated adequately, your immunity drops and one little germ can wreak havoc,” she adds (also see ‘Know’, below).
Madhu Handa, senior consultant in microbiology, Moolchand Medcity, New Delhi, agrees. “Exposure to germs makes our children less susceptible to bigger diseases and allergies in the long run, though it makes us vulnerable to a runny nose…which is really not a big deal,” she says.