With cleaning and disinfection, it is as bad to go over as not to arrive. While no one disputes that removing microbes from water or pasteurizing milk has helped reduce infant mortality and saved millions of lives, taking neatness to the extreme can have negative consequences. This is what the hygiene hypothesis defends, and there are more and more studies that agree with it.
Without going any further, a team of Swedish allergists recently showed that children who live in houses where dishes are washed by hand and food is bought directly from farms suffer fewer cases of asthma, rhinitis, conjunctivitis and eczema on the skin. Other research revealed that children who grow up in rural areas and in direct contact with animals develop fewer allergies than urban children, especially if microbes inhabit their sheets. In addition to that they also have fewer cases of autoimmune diseases such as multiple sclerosis, diabetes and psoriasis.
Dirty and sturdy
Although it seems a contradictory phenomenon, it has its logic. There are certain lymphocytes, normally responsible for responding to parasites, which reach too high amounts in children who live in extremely clean environments. Early contact with microorganisms is necessary so that our immune system has the correct proportions and learns to regulate itself. Otherwise, the overpopulation of cells specialized in defending ourselves against external aggressions can make our body too sensitive and tend to overreact to harmless substances and microbes.
Immunologists say that the microorganisms with which human beings evolved when we lived in contact with nature assumed the role of fine-tuning the regulatory mechanisms that allow our defenses to act properly. If we eliminate them with extreme neatness, almost obsessive, the immune system goes out of control. And it can attack harmless molecules, such as dust particles, and even cells of its own. The conclusion is clear: children must be allowed to get dirty in order for them to grow up healthy and strong.
Let them put their thumb in their mouth
The benefit of this was recently demonstrated by researchers at the University of Otago, New Zealand. After exhaustively monitoring the health of more than a thousand subjects from birth to age 40, they proved that those who sucked their thumbs and bit their nails at five, seven and even nine years , suffered 31% fewer skin allergies. Again, because they increased their exposure to microbes.
And what to do with the pacifiers that fall to the ground? Nothing to boil them to sterilize them. As you could read in the Pediatrics review, it is preferable that parents clean them by giving them a hickey or putting them in their mouth. Babies whose parents have this habit hardly develop asthma or dermatitis. According to the researchers, it is because microbes transmitted to them by adults through saliva positively stimulate their immature immune systems.
