Obese men are more likely to father children who go on to develop cancer, compared to men of normal weight, researchers from Duke Unviersity Hospital reported in BMC Medicine.

Previous studies showed that a mother's diet and weight might impact a child's health - even before he/she is born.

Hypomethylation of the gene coding for IGF2 (Insulin-like growth factor 2) in infants increases their risk of developing cancer when they are older. The researchers said that among babies whose fathers were obese, they found a drop in the amount of DNA methylation of IGF2 in the fetal cells that had been taken from cord blood.

The scientists gathered and examined data regarding parental weight and compared the epigenetic data of their offspring (newborns) - this was part of the Newborn Epigenetics Study (NEST). While DNA is the genetic data which children inherit from their parents, epigenetic imprinting controls how active these genes are.

IGF2 codes form a growth factor that is particularly crucial during a fetus' development. DNA hypomethylation, as well as other abnormal controls of this gene have been associated with cancer.

IGF2 was hypomethylated in infants with obese fathers, the researchers explained. This was not found in infants of obese mothers.

Study leader, Dr. Adelheid Soubry, said:

"During spermatogenesis some regions in the DNA may be sensitive to environmental damage; these effects can be transmitted to the next generation. It is possible that (mal)nutrition or hormone levels in obese fathers, leads to incomplete DNA methylation or to unstable genomic imprinting of sperm cells. Further research is necessary to confirm our findings."

Dr. Cathrine Hoyo, a NEST researcher, explained "In general, epigenetic marks are reprogrammed while sperm and eggs are being formed, and consequently nutrition, lifestyle or environment of the parents at this point in time can have a direct effect on a child's development and subsequent health."

The epigenetics of higher obesity rates through generations

Scientists from Baylor College of Medicine, who were researching on overweight pregnant mice, found that chemical changes in the ways genes are expressed (epigenetics) could affect future generations.

In an article published in the International Journal of Obesity, the researchers suggested that one of the reasons everybody is getting fatter and fatter is that maternal obesity before and during pregnancy impacts on the establishment of body weight regulatory mechanisms in the fetus/infant. In other words, maternal obesity could be promoting obesity in the next generation.

Written by Christian Nordqvist