Kids with obese parents are known to be at increased risk of childhood obesity themselves. Moms with unhealthy diets have been shown to pass along metabolic problems to their kids, but exactly how dads fit into the equation is unclear. In humans, this is particularly difficult because fathers and children often share not just genes, but a home environment as well.
Thankfully, we have rats to help sort this out.
Australian researchers fed some male rats a high-fat diet and kept others on a healthy diet. Both groups of rats mated with females, all of whom ate a healthy diet. Then the researchers studied the resulting female pups.
The pups born to overweight fathers were smaller than those with healthy fathers. When they grew up, the daughters of overweight fathers had the same amount of fat, muscle mass, triglycerides and leptin as daughters of healthy fathers. But there were differences – the rats whose dads ate the high-fat chow had impaired glucose tolerance and insulin secretion. The problems started earlier than for rats with healthy dads, and they got worse over time.
Genetic analysis revealed that 642 genes related to insulin and glucose metabolism were expressed differently in the daughters of overweight rats compared with the control rats. These so-called epigenetic changes affected the function of pancreatic cells that make insulin.
“To our knowledge, this is the first direct demonstration in any species that a paternal environmental exposure” – in this case, a high-fat diet – “can induce intergenerational transmission of impaired glucose-insulin homeostatis in their female offspring.”
The findings will be published in Thursday’s edition of the journal Nature.
-- Karen Kaplan/Los Angeles Times