A man’s weight may affect the heritable information contained in his sperm and could explain why children of obese fathers are more likely to be obese, according to a small study.
The research in the journal Cell Metabolism found that the sperm cells of lean and obese men possess different epigenetic marks, particularly in genes associated with appetite control. Epigenetics refers to the way that inherited genes can be modified by environmental factors.
Before and after weight-loss surgery
In order to test the theory, Danish researchers analysed the sperm of 6 obese men who were undergoing weight-loss surgery. Tests on the men’s sperm were carried out before surgery, soon after surgery and a year later.
They report 1,509 specific structural genetic changes a week after surgery and 3,910 changes after a year compared to the pre-surgery state.
The authors say it is early evidence that sperm carries information about a man’s health, although more research is needed to determine the effect these changes have on offspring.
Similar differences in sperm cells were noted when the researchers compared epigenetic changes in 13 lean men and 10 obese men.
Changing men’s behaviour
Lead researcher Romain Barrès, an associate professor at the University of Copenhagen, comments in a statement: ” Our research could lead to changing behaviour, particularly pre- conception behaviour of the father.
“It’s common knowledge that when a woman is pregnant she should take care of herself – not drink alcohol, stay away from pollutants, etc – but if the implication of our study holds true, then recommendations should be directed towards men, too.”
Professor Barrès says there is probably an evolutionary explanation for why information about a father’s weight would be valuable to offspring. He says that in times of abundant food supply it would be a way of programming children to eat more and grow bigger. “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.”
Commenting on the study in a statement, Allan Pacey, professor of andrology at the University of Sheffield, 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. Whilst the study examines a relative small number of individuals, 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.
“In my opinion, it’s far too preliminary to conclude what these observations may mean for human health and reproduction. There is much work in this area that still needs to be done. But the authors’ observations are credible and I would encourage them and others to investigate this phenomenon further.
“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.”
Source: Web MD
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