Researchers closely followed participants from mid-pregnancy into childhood and adolescence and examined fecal samples for infants at 3-4 months of age in addition to survey responses about their home and use of disinfectant products.
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Of the 757 infants profiled, 80 percent came from households that used disinfectant products on a weekly basis, typically multi-surface cleaners. The emphasis on cleanliness, researchers said, has led to widening use of the products.
In the study, they noted an increase of a gut bacteria called Lachnospiraceae in infant stool with increased use of disinfectants or eco-friendly cleaners, but they found no similar association when washing detergents without the bacteria-killing ingredients were used.
It's known "from animal studies that higher levels of Lachnospiraceae have been associated with higher body fat and insulin resistance," senior author Anita Kozyrskyj said in a podcast related to the research.
According to the findings, infants from households that used antimicrobial disinfectants weekly were twice as likely to have higher levels of Lachnospiraceae and then, after age 3, they were also more likely to have a higher body mass index than children from homes where disinfectants were not as frequently used.
In addition to higher levels of Lachnospiraceae, infants from frequent disinfectant use households had lowered abundance of Haemophilus and Clostridium bacteria, a combined profile similar to children with eczema.
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"Elevated fecal abundance of Lachnospiraceae (specifically Blautia) concurrent with lowered Haemophilus is also a signature of diabetes, as shown in a study on 11-year-old children," researchers wrote.
“These results suggest that gut microbiota were the culprit in the association between disinfectant use and the overweight,” Kozyrskyj added in the podcast interview.
Gut microbiota, gut flora or gastrointestinal microbiota refers to the "complex community of microorganisms that live in the digestive tract," according to the National Institutes of Health.
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“Indeed, concerns over the potential for antibacterial products to be too effective or even toxic has motivated use of “green” or eco-friendly alternatives,” researchers said.
But though eco-friendly alternatives showed different microbiota and lower levels of the bacteria Enterobacteriaceae, plus lower rates of overweight children, study authors didn't provide a link between the altered gut microbiota and reduced childhood obesity or overweight risk.
Due to the lack of convincing data, Kozyrskyj told CNN she's not ready to recommend eco-friendly alternatives, but she has personally switched out popular disinfectants with DIY vinegar cleaning solutions.
Kozyrskyj and her colleagues concluded that antibacterial cleaning products “have the capacity to change the environmental microbiome and alter risk for child overweight,” but further research into the mechanisms through which the products alter gut microbiota and the impact on metabolism is needed.
Read the full study at cmaj.ca.