High-fat diet in pregnancy risks heart problems in offspring

Babies born to women consuming a high-fat, sugary diet are at risk of cardiovascular disease and diabetes in later life, according to a new study led by the University of South Australia (UniSA).

Researchers identified the link by analysing tissue samples from the fetuses of pregnant baboons fed a high-fat, high-energy diet in a biomedical research institute in the United States. They then compared this to fetuses from baboons on a control diet.

UniSA PhD candidate Melanie Bertossa said the findings, published in The Journal of Physiology, demonstrate a clear link between an unhealthy diet high in saturated fats and sugar and poor cardiovascular health.

“There has been a longstanding debate as to whether high-fat diets induce a hyper- or hypothyroid state in the fetal heart; our evidence points to the latter,” said Bertossa, who served as lead author on the study.

“We found that a maternal high-fat, high-energy diet reduced concentrations of the active thyroid hormone T3, which acts like a switch around late gestation, telling the fetal heart to start preparing for life after birth. Without this signal, the fetal heart develops differently.”

Bertossa said that diets high in fat and sugar can also alter the molecular pathways involved in insulin signalling and critical proteins involved in glucose uptake in the fetal heart. This increases the risk of cardiac insulin resistance, often leading to diabetes in adulthood. This is despite babies being a normal weight at birth.

“You’re born with all the heart cells you will ever have,” she said. “The heart doesn’t make enough new heart muscle cells after birth to repair any damage, so changes that negatively impact these cells before birth could persist for a lifetime.

“These permanent changes could cause a further decline in heart health once children reach adolescence and adulthood when the heart starts to age.”

UniSA’s Professor Janna Morrison said the study demonstrates the importance of good maternal nutrition in the lead-up to pregnancy, not only for the mother’s sake but also for the health of the baby.

“Poor cardiac outcomes were seen in babies that had a normal birth weight — a sign that should guide future clinical practice,” said Morrison, senior author on the study.

“Cardiometabolic health screening should be performed on all babies born from these types of pregnancies, not just those born too small or too large, with the goal being to detect heart disease risks earlier.”

The researchers are currently undertaking long-term studies of babies born to women on high-fat, high-energy diets to track their health over decades. Morrison is concerned that if rising rates of these diets are not addressed, more people will develop health complications resulting in shorter lifespans in the decades ahead.

“Hopefully, with the knowledge we have now about the negative health impacts of obesity, there is potential to change this trajectory,” she said.

Image credit: iStock.com/Mykola Sosiukin