Maternal Exercise During Pregnancy Epigenetically Improves Future Health of a Child, Regardless of Parental Weight

It’s never too late to exercise – even if you’re pregnant. Not only does it benefit the mother by reducing her chances of getting gestational diabetes or other possible complications, but it will also improve the baby’s total health. New research reveals that exercise could even prevent certain metabolic disorders from being passed on from overweight parents, and the findings point to epigenetics.

Women have always been encouraged to eat right and maintain a healthy weight during pregnancy. But many times, the mother is already overweight before conception, and the father may be as well. Unfortunately, children born to obese parents have a higher risk of developing metabolic disorders like diabetes, kidney damage, and heart disease later on in life. Besides, these children will most likely fall into the obese category as adults themselves, passing the same vulnerability on to their own offspring in a vicious cycle of transgenerational disease transmission.

However, expecting moms who are overweight don’t have to panic that it’s too late to make up for bad habits. Getting physically active during their pregnancy can help prevent complications and benefit the long-term health of their children. According to a study out of the University of Virginia (UVA) School of Medicine, exercise during gestation can actually protect the growing embryo from acquiring the harmful effects of parental obesity by offsetting abnormal DNA methylation transmission to the offspring.

DNA methylation is one of the most applicable and well-studied epigenetic mechanisms known to affect gene activity. It comprises the covalent addition of a methyl group (-CH3) onto the fifth position of cytosine, resulting in 5-methylcytosine (5-mC). DNA methylation modifications are dynamic and can be altered by environmental stimuli. It can also remain stable and pass on to future generations. This phenomenon is called transgenerational epigenetic inheritance, and it explains how some acquired traits and conditions are handed down through generations.

Prior studies investigating DNA methylation’s role in the deregulation of important metabolic pathways have found that it relates to an increased predisposition for obesity along with its comorbidities. For instance, maternal obesity in mice induced by a diet high in fat causes hypermethylation of the Pgc-1α gene, a key regulator of energy metabolism. This gene has also been found to be hypermethylated in subjects with type 2 diabetes.

“Most of the chronic diseases that we talk about today are known to have a fetal origin,” said Zhen Yan, Ph.D., a top exercise researcher at UVA’s School of Medicine. This is to say that the parents’ poor health conditions prior to and during pregnancy have negative consequences to the child, potentially through chemical modification of the genes.”

Inspired by previous research indicating that regular exercise done before and during pregnancy saves the offspring from developing early-onset diabetes, Yan and his team posed the questions, “what if an obese mother exercises only during pregnancy, and what if the father is obese?”  He also wanted to assess how long the benefits would last, something other studies have not yet measured.

The team conducted their study on mice, feeding some a normal chow diet before and during pregnancy, while the others were fed a high-fat diet (HFD) to simulate obesity. Of the HFD mice, some were given access to a running wheel for voluntary exercise only during pregnancy, while others were kept sedentary without access to much activity.

The results showed significant differences in metabolic health and gene activity among the groups. The mothers and fathers in the HFD group had offspring that were vulnerable to metabolic disorders, especially the male offspring of the sedentary HFD dams, which had higher incidences of high blood sugar and other metabolic problems as adults.

The big take-a-way from the study was that maternal exercise done solely during pregnancy blocked any of the adverse epigenetic modifications HFD parents acquired from transmitting to their offspring’s genetic makeup. As the first study to show evidence of this kind, it is hoped that more studies will confirm the benefits of exercise during pregnancy. If these findings hold true in humans, the implications will be significant for helping expecting mothers ensure that their children grow up to live their best and healthiest life possible.

“Regular exercise is probably the most promising intervention that will help us deter the pandemic of chronic diseases in the aging world,” says Yan, “as it can disrupt the vicious cycle of parents-to-child transmission of diseases.

Source: Rhianna C., et al. Exercise during pregnancy mitigates negative effects of parental obesity on metabolic function in adult mouse offspring. Journal of Applied Physiology, 2021; 130 (3): 605.

Reference: Joshua Barney. Exercise During Pregnancy May Save Kids From Health Problems as Adults. University of Virginia Health System, March 11, 2021.

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