Your father's diet before you were born could have affected your health, a new study suggests

Your father's diet before you were born could have played a role in your health, a new study has found.

Released earlier this month in Nature, the study from German research group Helmholtz Munich looked at health data from more than 3,000 families. In all, they found a trend linking fathers' bodyweight and their children's, even when accounting for genetics, maternal health and environmental factors.

But laboratory testing conducted as part of the study may indicate that the impacts come down to a small window of time around conception; perhaps a matter of days or weeks.

"Our results suggest that preventive health care for men wishing to become fathers should receive more attention and that programs should be developed for this purpose, especially with regard to diet," Raffaele Teperino, head of Helmholtz' environmental epigenetics department, said in a press release.

"This can reduce the risk of diseases like obesity and diabetes in children."

Eating for two

To corroborate the relationships found in the human-family data, researchers ran laboratory tests in mice, examining sperm samples of specimens exposed to high- and low-fat diets.

Mice given food higher in fat for just two weeks were found to produce offspring with higher risk of metabolic disease, including in some cases a lower tolerance for sugar and a resistance to insulin — traits central to diabetes.

Comparing their findings among mice against human genome data, the researchers identified similar genetic signatures between the high-fat, sugar-intolerant mice and childhood obesity in humans.

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Also notable, though, was that when mice in the high-fat group returned to normal diets for four more weeks, none of the same impacts were seen in their offspring.

The study concluded that the high-fat impacts were reversible, meaning a would-be father who's been eating poorly may be able to undo the effects if they eat a healthier diet shortly before conception, at least in the case of the mice.

Wouldn't put it past him

The study joins a growing body of research into the mitochondrial RNA (mt-RNA), genetic material separate from the nucleus of each of the body's cells that can influence which genes are active, early in development.

Previously, scientists understood that mt-RNA from the mother's side could impact children's health, but research like the Helmholtz study points to a more balanced view between parents.

"Previously, it was assumed that fathers had no part in the genetic makeup of their offspring's mitochondria," reads the release. "Recent studies like this one now show that sperm carry fragments of mt-RNA … into the egg during fertilization."

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While maternal body mass index (BMI) has traditionally been associated with health outcomes for children, further analysis by the Munich team found that among families with low-BMI mothers, a high-BMI father doubles the obesity risk of the child, alongside impacts on insulin sensitivity.