Our obsession with domestic hygiene, promoted through increasingly intensive advertisements, could be detrimental to children’s health, because – according to a study published in the Canadian Medial Association Journal – they alter intestinal bacteria (microbiome) and, hence, children’s metabolism. The result: new-borns exposed to excessively strong domestic disinfectants could be more likely to be overweight or obese when they grow up.

The research was carried out by a team from the University of Alberta (Canada), using the data of 757 infants that had been recruited into a major study called Canadian Healthy Infant Longitudinal Development (CHILD). In particular, pediatricians from the University of Alberta examined the intestinal microbiome of these infants at the age of between three and four months’ old, and then measured the weight of the same infants at the age of one and then three years’ old, noticing, in fact, that there was a link between the exposure to strong disinfectants (due to parents’ choice) and microbiome composition, and that the infants in this case were overweight. In particular, the infants that were more in contact with strong soaps and disinfectants had microbiome with higher concentrations of Lachnospiraceae bacteria and lower concentrations, compared to the average, of Haemophilus-type bacteria. On the contrary, the bacterial flora of the infants living in households using eco-friendly or weaker detergents were closer to the average for that age group.

It cannot be shown with complete confidence, as the researchers themselves admit, that the changes in the infants’ microbiome are the direct cause of their weight increase. There could also be other explanations: including, for example – as the researchers write – the fact that the mothers accustomed to using eco-friendly detergents are, in general, more health-conscious and therefore also more attentive to the weight of their children. For some time, however, the excessive use of detergents has been a subject in the firing line, especially due to the negative effects that it can have on the “maturing” of the immune system. Hygiene is fundamental, of course, but it is just as important – explain the researchers – for the defence system of small children to be in contact with the widest possible range of “enemies” (antigens), so that they can develop correctly, and thus facilitate all the functions of the body, including metabolism.

Journalist since 1983, has been dealing with scientific divulgation for years, especially in the fields of medicine and biology. Creator of Sportello Cancro, the site created by corriere.it on oncology, in collaboration with the Umberto Veronesi Foundation. He collaborated with the pages of the Science of Corriere della Sera for several years. He is currently President of the Lugano Science Foundation.