Children whose parents consume a high-fat diet are more likely to develop obesity and diabetes, according to research published in Nature Genetics. The study indicates that epigenetic factors are directly transmitted through sperm and eggs.
In recent decades, the world has seen a rise in diabetes so rapid that it seems unlikely that DNA mutations are to blame.
Epigenetic inheritance, on the other hand, could offer some explanation as to the sudden expansion of the condition.
While parents transmit genetic information to their children through DNA, scientists now believe that epigenetic modifications may also be passed on to the offspring's genetic material.
Epigenetic inheritance refers to the passing on of traits that do not feature in the DNA, or genes. Epigenetic information is currently thought to involve RNA transcripts and chemical modifications of the chromatin.
Could environmental influences on parents affect their children?
According to the authors of the current study, both Jean-Baptiste Lamarck and Charles Darwin hypothesized that parents could pass on to their children traits that they acquire as a result of exposure to environmental influences.
However, the extent to which environmental conditions impact future outcomes remains unclear.
Factors that affect the offspring's future health outcomes are thought to include what the mother consumes while she is pregnant or lactating, which molecules are present in the father's semen and the microbiota of either parent.
Peter Huypens, of Helmholtz Zentrum München in Germany, and colleagues fed mice a high-fat, low-fat or normal diet over a period of 6 weeks. The mice were genetically identical.
Mice that consumed a high-fat diet developed obesity and glucose intolerance.
The team then created a new generation by implanting embryos using sperm and eggs from the mice that had eaten different diets into healthy surrogate mothers.
The use of surrogates enabled them to separate environmental factors from the epigenetic factors that were present only in the sperm or eggs.
Parental diet impacts offspring's susceptibility
The new generation of mice then consumed a high-fat diet.
Offspring of two obese parents gained significantly more weight on a high-fat diet than those with only one obese parent. Offspring of two lean parents gained the least weight on a high-fat diet. Similar patterns emerged for glucose intolerance.
However, female offspring were more prone to severe obesity, while males were more affected by blood glucose levels than females.
Maternal influence also appeared to be greater than that of the father. Lead author Prof. Johannes Beckers says this is also true for humans.
The authors conclude that epigenetic factors in gametes play an important role in passing on the risk of obesity and diabetes from parents to offspring.
Prof. Martin Hrabě de Angelis, director of the Institute of Experimental Genetics (IEG), who initiated the study, says:
"This kind of epigenetic inheritance of a metabolic disorder due to an unhealthy diet could be another major cause for the dramatic global increase in the prevalence of diabetes since the 1960s."
The researchers believe this is the first study to demonstrate that offspring can inherit an acquired metabolic disorder epigenetically, through eggs and sperm, in keeping with the theories of Lamarck and Darwin.
Medical News Today recently reported on the establishment of microbiota in infants. The inherited microbiome is thought to affect children's chance of developing conditions such as obesity in later life.