Household
cleaning products may contribute to kids' overweight by altering their gut
microbiota
Canadian Medical Association Journal
Commonly used household cleaners
could be making children overweight by altering their gut microbiota, suggests
a Canadian study published in CMAJ (Canadian Medical
Association Journal).The study analyzed the gut flora of 757 infants from the general population at age 3-4 months and weight at ages 1 and 3 years, looking at exposure to disinfectants, detergents and eco-friendly products used in the home.
Researchers from across Canada
looked at data from the Canadian Healthy Infant Longitudinal Development
(CHILD) birth cohort on microbes in infant fecal matter. They used World Health
Organization growth charts for body mass index (BMI) scores.
Associations with altered gut flora in babies 3-4 months old were strongest for frequent use of household disinfectants such as multisurface cleaners, which showed lower levels of Haemophilus and Clostridium bacteria but higher levels of Lachnospiraceae.
The researchers also observed an increase in Lachnospiraceae bacteria with more frequent cleaning with disinfectants. They did not find the same association with detergents or eco-friendly cleaners. Studies of piglets have found similar changes in the gut microbiome when exposed to aerosol disinfectants.
"We found that infants living
in households with disinfectants being used at least weekly were twice as
likely to have higher levels of the gut microbes Lachnospiraceae at age 3-4
months; when they were 3 years old, their body mass index was higher than
children not exposed to heavy home use of disinfectants as an infant,"
said Anita Kozyrskyj, a University of Alberta pediatrics professor, and
principal investigator on the SyMBIOTA project, an investigation into how alteration
of the infant gut microbiome impacts health.
Babies living in households that
used eco-friendly cleaners had different microbiota and were less likely to be
overweight as toddlers.
"Those infants growing up in
households with heavy use of eco cleaners had much lower levels of the gut
microbes Enterobacteriaceae. However, we found no evidence that these gut
microbiome changes caused the reduced obesity risk," she said.
She suggests that the use of
eco-friendly products may be linked to healthier overall maternal lifestyles
and eating habits, contributing in turn to the healthier gut microbiomes and
weight of their infants.
"Antibacterial cleaning
products have the capacity to change the environmental microbiome and alter
risk for child overweight," write the authors. "Our study provides
novel information regarding the impact of these products on infant gut
microbial composition and outcomes of overweight in the same population."
A related commentary provides
perspective on the interesting findings.
"There is biologic plausibility
to the finding that early-life exposure to disinfectants may increase risk of
childhood obesity through the alterations in bacteria within the Lachnospiraceae
family," write epidemiologists Dr. Noel Mueller and Moira Differding,
Johns Hopkins Bloomberg School of Public Health, in a related commentary.
They call for further studies
"to explore the intriguing possibility that use of household disinfectants
might contribute to the complex causes of obesity through microbially mediated
mechanisms."
Dr. Kozyrskyj agrees and points to
the need for studies that classify cleaning products by their actual
ingredients. "The inability to do this was a limitation of our
study."
The research study was funded by the
Canadian Institutes of Health Research (CIHR) with funding from the Allergy,
Genes and Environment (AllerGen) Network of Centres of Excellence for the CHILD
study.
