WASHINGTON — Obese mothers tend to have kids who become obese. Now provocative research suggests weight-loss surgery may help break that unhealthy cycle in an unexpected way — by affecting how their children's genes behave.
In a first-of-a-kind study, Canadian researchers tested children born to obese women, plus their brothers and sisters who were conceived after the mother had obesity surgery. Youngsters born after mom lost lots of weight were slimmer than their siblings. They also had fewer risk factors for diabetes or heart disease later in life.
More intriguing, the researchers discovered that numerous genes linked to obesity-related health problems worked differently in the younger siblings than in their older brothers and sisters.
Clearly diet and exercise play a huge role in how fit the younger siblings will continue to be, and it's a small study. But the findings suggest the children born after mom's surgery might have an advantage.
"The impact on the genes, you will see the impact for the rest of your life," predicted Dr. Marie-Claude Vohl of Laval University in Quebec City. She helped lead the work reported Monday in the journal Proceedings of the National Academy of Sciences.
Why would there be a difference? It's not that mom passed on different genes, but how those genes operate in her child's body. The idea: Factors inside the womb seem to affect the dimmer switches that develop on a fetus' genes — chemical changes that make genes speed up or slow down or switch on and off. That in turn can greatly influence health.
The sibling study is "a very clever way of looking at this," said Dr. Susan Murphy of Duke University. She wasn't involved in the Canadian research but studies uterine effects on later health. She says it makes biological sense that the earliest nutritional environment could affect a developing metabolism, although she cautions that healthier family habits after mom's surgery may play a role, too.
It's the latest evidence that the environment — in this case the womb — can alter how our genes work.