Diet-Induced Obesity Is Transmitted Through The Germline

To anyone following the “biological” literature on obesity, it should be pretty evident by now that environmental factors can epigenetically modify genes in ways that allow “information” on environmental exposures in parents to be directly transmitted to their offspring.

Now a paper by Peter Huypens and colleagues from the Helmholtz Zentrum München, Germany, published in Nature Genetics, shows that both maternal and paternal exposure to weight gain induced by a high-fat diet in mice can substantially increase the risk for obesity in their offspring.

The key novelty in this study was the fact that the researchers isolated egg and sperm from both male and female mice that had been exposed to high-fat diets (or not) and used these germ cells in various combinations using in-vitro fertilization to create the offspring that were then implanted into surrogate female mice.

In all cases, risk for obesity as well as signs of insulin resistant tracked with both the male and female exposures, pretty much confirming that diets eaten by mothers and fathers can directly influence “genetic” risk for obesity in the next generation.

If transferable to humans (and there is little reason to doubt that this is the case), these findings suggest that a large proportion of the “heritability” of obesity is due to epigenetic modification that transfers risk from one generation to the next.

This means that efforts to prevent childhood obesity need to focus on the parents rather than the kids – kids born to mothers and fathers who have obesity are already born with a substantial higher risk than those born to lean mothers and fathers.

Perhaps our best chances of tackling obesity in the next generation of kids is to focus efforts on younger adults of child-bearing age.

@DrSharma
Edmonton, AB