Breastfeeding and childhood obesity

Breastfeeding can help reduce a child’s risk for obesity, says a new international study led by researchers at the University of Toronto.

“The benefits of breast milk are well known. However, what is new is to find that breastfeeding can have a significant impact on children who have a genetic predisposition to obesity,” said Dr. Laurent Briollais, assistant professor with the Dalla Lana School of Public Health at the University of Toronto and senior investigator with Mount Sinai’s Samuel Lunenfeld Research Institute.

Almost a third of Canadian children aged five to 17 are overweight or obese, according to Statistics Canada.

Briollais, principal investigator of the study, worked with collaborators in Australia, as well as his postdoctoral student, Dr. Taraneh Abarin, and Dr. Stephen Lye, executive director of U of T’s Fraser Mustard Institute for Health Development and associate director of Mount Sinai’s Samuel Lunenfeld Research Institute.

Their research revealed that the length of time a baby is breastfed positively affects the function of the fat mass and obesity gene (FTO) in young adults. The study, published Nov. 15 in the International Journal of Epidemiology, followed children in Western Australia from birth to age 14.

For years, body mass index (BMI) has been used by scientists to track weight problems and obesity in children and adults. Previous studies have connected a common variant of the FTO gene to increased risk of obesity in young adults. This study finds that breastfeeding can help reverse the effects of the FTO gene variant if a child is exclusively breastfed for at least three months.

"Childhood obesity is a serious problem, and it will likely impact chronic diseases in the long-term, as well as increased health care costs," said Briollais.

An estimated 70 per cent of children in Canada possess at least one copy of the specific variant of the FTO gene responsible for increased BMI and obesity. The increase in BMI in children affected by this gene is seen as early as six years.

“This study is one of the first examples of early intervention in the fight against obesity,” said Lye. “Rather than trying to treat the symptoms later, we’re better off trying to prevent them in the first place.”

The study was supported with funding from the Canadian Institutes of Health Research (CIHR) and The Alva Foundation.