Dad’s beer belly might affect the eating behaviour and overall health of his children, researchers have found in a new study. The idea of obese parents influencing their children is nothing new; however, the father’s individual role in the matter may be more significant than previously thought. Researchers at the University of Denmark believe they have found evidence that ‘markers’ on the sperm that correspond to the owner’s genes can predispose potential children to obesity.
The study examined the differences between obese men and men of normal weight, with large differences being observed in their sperm. When some men in the study had gastric bypass surgery (GBP), markers in their sperm changed over time as they revised their diet and lifestyle following the procedure. This relationship between genetic data and lifestyle changes could lead to methods of preventing the transmission of obesity and other disorders from parents to their offspring.
“Today, we know that children born to obese fathers are predisposed to developing obesity later in life, regardless of their mother’s weight,” explained Dr. Ida Donkin, a researcher at the University of Copenhagen, in a press release. “It’s another critical piece of information that informs us about the very real need to look at the pre-conception health of fathers. And it’s a message we need to disseminate in society.”
The first segment of the study had researchers comparing sperm cells from 13 men with an average BMI of 22.9 and 10 obese men with an average BMI of 31.8. They found that even the way that the sperm acted and looked appeared to differ before noting the hundreds of differences in genetic expressions between the two groups. Most prominent were differences in epigenetic markers found in gene regions associated with appetite.
In the second part of the study, the team of researchers followed six men before and up to a year after gastric bypass surgery. After only weeks after surgery, they found 3,000 differences in epigenetic patterns of their sperm. After a year, that number rose above 5,000.
The researchers admit that they are not sure exactly how this works yet, but they maintain that these developments strengthen the idea that we genetically inherit many aspects of our lifestyle from our parents.
“We certainly need to further examine the meaning of these differences; yet, this is early evidence that sperm carries information about a man’s weight. And our results imply that weight loss in fathers may influence the eating behaviour or their future children,” says Romain Barrès from the Novo Nordisk Foundation Center for Basic Metabolic Research.
Barrès is now collaborating with a fertility clinic to conduct further research. By law in Denmark, embryos must be discarded after five years and can be used for research. Thus Barrès is now looking at the epigenetic differences in the discarded embryos made from the sperm of men with various BMI’s. Additionally, cord blood from children of men with various degrees of body weight will be examined, but it will take a while before they accumulate enough participants.
“It is clear that these epigenetic changes happen in mice and rats,” he says, “but we also need to know if this also happens in humans and whether this is a significant driver for changing our traits.”