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What your parents ate before you were born might affect your risk of obesity and diabetes

*Waggles finger disapprovingly at parents*

PETER DOCKRILL
15 MAR 2016
 

It's well-known that the food your parents eat and the kind of kitchen they run when you're growing up can have a major impact on how your own dietary health pans out, but what about their eating habits before you were even born?

New research in mice has found that the food parents eat before their offspring come into the world can also end up affecting the next generation's health. In the study, researchers found that mice fed a high-fat diet rendered their offspring more susceptible to developing obesity and diabetes – even when the babies were carried by and born to healthy surrogate mothers, ruling out the impact of any subsequent behaviour on the part of the biological parents during pregnancy and thereafter.

 

The study provides the latest evidence of epigenetics – the remarkable and somewhat counterintuitive science that explains how we can inherit some traits via external or environmental factors in addition to the genetic information encoded in our DNA.

"From the perspective of basic research, this study is so important because it proves for the first time that an acquired metabolic disorder can be passed on epigenetically to the offspring via oocytes and sperm," said researcher Johannes Beckers from the German Research Centre for Environmental Health.

To isolate whether parental diets in themselves could affect offspring health outside of a behavioural context, the researchers fed groups of genetically identical mice one of three diets: high fat, low fat, or standard lab chow. After six weeks, the mice on high-fat food had become obese and showed an impaired tolerance to glucose – an early sign of type 2 diabetes.

The scientists then took eggs and sperm cells from each of the three groups and impregnated healthy female mice via in vitro fertilisation (IVF).

When the offspring born via IVF were in turn fed high-fat diets, the animals whose biological parents had been obese in the first stage of the experiment were more prone to gaining weight and developing glucose intolerance themselves – especially if both parents had been obese. In contrast, the offspring of two mice on the low-fat diet gained the least weight when fed the high-fat diet.

"[The study] shows that metabolic alterations in the offspring are more important if both eggs and sperm have been collected from high-fat-diet fed animals, suggesting the effect of maternal and paternal diet are additive," Romain Barrès, a molecular biologist from the University of Copenhagen, who was not involved with the study, told Linda Geddes at Nature.

The findings, published in Nature Genetics, suggest that female offspring are more prone to gaining weight when the parents had been obese, whereas male offspring were more prone to developing glucose intolerance. The scientists don't fully understand why this is the case, and will be looking at studying further how these traits are passed on in future research.

So far, these results have only been found in mice, and there's no guarantee that the same outcomes would necessarily be replicated in humans, so don't freak out just yet. That said, epigenetics is a field of intense interest to researchers right now, and we do know that humans do pass on epigenetic information. We just have to figure out if parents' pre-pregnancy diets are a part of that.

If the dietary inheritance system shown in mice does turn out to apply to humans, this sort of external influence on our tendency to gain weight (or not) could help explain a bit about health dilemmas in the world today.

"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," said one of the researchers, Martin Hrabě de Angelis.

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