Scientists have long speculated about why obesity tends to run in families. While some of the blame can be chalked up to simply growing up in the same household and eating the same food, the earliest days we spend in the womb may especially influence our obesity risk. Now, a new study published in the International Journal of Obesity suggests that the umbilical cord can provide us with clues as to how that happens.

Researchers examined cells taken from the umbilical cords of over 30 Brazilian mothers soon after they gave birth, 24 of whom were obese or overweight before the pregnancy. They found that the more obese the mother was, the less likely her umbilical cells expressed genes known to be important in regulating metabolism. The tweaks found in these cells, some of which have been seen in people with obesity and type 2 diabetes, involved the regulation of mitochondria (the structures found in our cells that produce energy) and lipid metabolism.

"This suggests that already at birth there are detectable metabolic perturbations resulting from maternal obesity," said study co-author Dr. Elvira Isganaitis, a professor of pediatrics at Harvard Medical School and staff endocrinologist at Joslin Diabetes Center, in a statement.

The cells were specifically taken from the vein responsible for providing oxygen and nourishment to the developing fetus. "These samples give a window into the nutrients and metabolites that are coming from the mom into the infant," explained Isganaitis.

In the case of obese mothers, Isganaitis and her colleagues speculate, the types of nutrients they’re passing down may very well be harmful to the future metabolic health of their children. Adding support to that theory, Isganaitis said the tested fetal blood of children born to obese mothers “had significantly higher levels of many lipids that are known to be metabolically deleterious, like saturated fatty acids.” These fatty acids, shed from the mother’s fatty tissues, may in turn create a sort of “fuel overload” in the developing embryo, she added.

Because their research is admittedly in the early stages, Isganaitis’ team will continue tracking children born closer to home in the Boston area to see if the connection between umbilical cells and obesity risk remains present. Eventually, they hope their research (and that of others) can amount to real-life implications for prenatal care, such as developing tests that can detect obesity biomarkers in the womb, which could then lead to recommended lifestyle changes.

"Pregnant women engage often with their healthcare providers, and you can really tap into their motivation," she explained. "If we could come up with tailored interventions — if we could say, take this vitamin, exercise regularly and you can minimize obesity or diabetes risk in your child — I'm sure mothers would do it."

Even for those of us who start off with a higher risk for obesity, though, there’s no need to see that as a certainty, according to Isganaitis. Or to assume that our later life experiences and decisions can’t affect that risk in either direction.

"Your risk of chronic diseases isn't set in stone at birth; there are many different periods in which your lifelong disease risk can be modulated," she said.

Source: Costa S, Isganaitis E, Matthews T, et al. Maternal obesity programs mitochondrial and lipid metabolism gene expression in infant umbilical vein endothelial cells. International Journal of Obesity. 2016.

Read More:

Mothers Gaining Weight Excessively During Pregnancy May Put Newborn Babies At Risk Of Childhood Obesity. Read here.

Mother's Breast Milk May Influence Risk Of Obesity In Children, As Their Gut Microbiomes Are Built Early. Read here.