Father’s weight prior to conception could affect that of his children, suggests study

Father and Baby

Researchers in Denmark believe they may have identified a link between paternal weight and a possible predisposition for obesity in children.

The scientists found that the sperm cells of obese men and men who were not overweight had differing epigenetic markers, which regulate the way genes behave.

Researchers at the University of Copenhagen examined the sperm cells of six morbidly obese men who were about to undergo weight-loss surgery. New samples were collected one week after surgery and again after a period of 12 months.

Lead author Dr Romain Barres says epigenetic changes were noticeable in both the second and third round of samples and while a solid scientific conclusion for how these changes could affect any potential offspring remains to be drawn, he says the recorded changes can be linked to the recognised genes relating to appetite control and brain development.

The five-year study, published in the journal Cell Metabolism, also recorded similar sperm cell changes when comparing samples from 13 men with a BMI of below 30 with those from 10 moderately obese men.

Evolutionary advantage

Dr Barres suggests that one reason for the epigenetic markers could be evolutionary advantage - whereby information about a father's weight could be of some value to his offspring.

Fathers Weight

He theorises that during times of abundance, it could be nature’s way of encouraging children to instinctively eat more and grow bigger while times are good and food is plentiful.

"It's only recently that obesity is not an advantage," he says. "Only decades ago, the ability to store energy was an advantage to resist infections and famines."

“Intriguing” findings

Professor Allan Pacey, Professor of Andrology at the University of Sheffield, who describes the findings as “intriguing”, says: “This is an interesting study which provides further evidence to support the theory that some characteristics can be passed by sperm from a father to his children, without altering the basic structure of the genetic code.” He adds: “The fact that such significant differences can be found in the epigenetic markers of lean and obese men is intriguing and in my opinion worthy of more detailed investigation. In addition, the fact that changes can be seen in men before and after significant weight loss also adds some validity to the findings.”

However, Professor Pacey cautions that it is too early to conclude what the observations could mean for human health and reproduction at this point, and encourages further research.

He adds: “Until we know more, would-be parents should just aim to be as healthy as possible at the time of conception and not be drawn to faddy diets or other activities in order to try and influence the health of their children in ways we don’t properly understand.”

Professor Marcus Pembrey, Emeritus Professor of Paediatric Genetics, Institute of Child Health, UCL, and Visiting Professor, University of Bristol, says: “The similar correlation between father’s and mother’s BMI and that of their offspring has been a puzzle, given that the mother nurtures the baby in the womb and into infancy.”

Baby Sleeping

He describes the study as “the first comprehensive epigenetic profiling of human sperm in relation to obesity” and says it has set the ball rolling in terms of investigation into the effects of obesity on sperm. He adds that, while showing obesity-related epigenetic changes in sperm is a long way from knowing how and if these changes contribute to the paternal effect on offspring BMI, it shouldn’t stop fathers from setting a good example to their children by keeping their weight in check.

Dr Barres adds: “When a woman is pregnant she should take care of herself. But if the implication of our study holds true, then recommendations should be directed towards men too."

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