Mediterranean-style diet may lower preeclampsia risk, especially in Black women

Following a Mediterranean-style diet during pregnancy may lower the risk for preeclampsia, a blood pressure-related complication that can be fatal, new research shows.

The study, published Wednesday in the Journal of the American Heart Association, found Black women, who are at higher risk for preeclampsia than their white peers, had the biggest gains in risk reduction the more they adhered to this eating pattern compared to their non-Black peers.

"The U.S. has the highest maternal mortality rate among developed countries, and preeclampsia contributes to it," Dr. Anum S. Minhas said in a news release. Minhas is chief cardiology fellow and a cardio-obstetrics and advanced imaging fellow at Johns Hopkins University in Baltimore.

Preeclampsia, characterized by severely high blood pressure and liver or kidney damage, is a serious complication that affects 5%-10% of pregnant women worldwide. It can be fatal to mother and child and more than doubles a woman's risk for long-term cardiovascular disease, including chronic high blood pressure, stroke, heart disease and heart failure. Women with this condition are more likely to give birth prematurely and their children are at higher risk for developing high blood pressure and heart disease.

"Given these health hazards to both mothers and their children," Minhas said, "it is important to identify modifiable factors to prevent the development of preeclampsia, especially among Black women who are at the highest risk of this serious pregnancy complication."

Preeclampsia and heart disease share several risk factors, including high blood pressure, diabetes and obesity. The Mediterranean-style eating pattern – with its focus on vegetables, fruits, legumes, nuts, olive oil, whole grains and fish – has been shown to reduce the risk for heart disease in adults. The new study looked at whether this eating pattern could lower the risk for preeclampsia for all women, but especially those at high risk.

Researchers analyzed health and dietary data for 8,507 women enrolled in the Boston Birth Cohort between 1998 and 2016. The women were 25 years old on average and were recruited from Boston Medical Center, which serves a low-income, largely under-resourced racial and ethnic population. Nearly half the women were Black, 28% were Hispanic and the remainder were white or of unspecified race. About 10% of the participants developed preeclampsia.

Overall, women who ate a Mediterranean-style diet during pregnancy had more than 20% lower odds of developing the condition. When researchers analyzed the data among Black women, they found even bigger gains among those who adhered most closely to the Mediterranean diet.

"This is remarkable because there are very few interventions during pregnancy that are found to produce any meaningful benefit," Minhas said. "And medical treatments during pregnancy must be approached cautiously to ensure the benefits outweigh the potential risks to the mother and the unborn child."

Women who had heart-related risk factors before pregnancy were at much higher risk for preeclampsia, the study found. Diabetes and obesity before pregnancy carried twice the risk of preeclampsia, and women with high blood pressure were nine times more likely to develop preeclampsia.

"Women should be encouraged to follow a healthy lifestyle, including a nutritious diet and regular exercise, at all stages in life," Minhas said. "Eating healthy foods regularly, including vegetables, fruits and legumes, is especially important for women during pregnancy. Their health during pregnancy affects their future cardiovascular health and also impacts their baby's health."

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