A Mediterranean-style diet is known to help protect the heart, and now new research suggests it can also lower an expectant mother's risk for life-threatening preeclampsia.
Marked by a sudden spike in blood pressure, protein in urine, or other problems during pregnancy, preeclampsia can cause serious health problems for moms and babies when left untreated. The condition also increases a woman's risk of heart disease later in life.
The traditional heart-healthy Mediterranean diet is rich in fruits, vegetables, fatty fish, whole grains, legumes and healthy fats such as olive oil.
The new study wasn't designed to see how, or even if, this style of eating lowers the risk for preeclampsia in pregnant women; it only found an association. But researchers have some theories about how it might do so.
"Some studies show that a Mediterranean diet can reduce oxidative stress and improve vascular function" or blood vessel flexibility, said study author Dr. Anum Minhas. She's a fellow in cardiology, cardio-obstetrics and advanced imaging at Johns Hopkins University in Baltimore. When blood vessels around the uterus constrict during pregnancy, it can cause high blood pressure.
"It's also possible that this diet lowers pregnancy weight gain," Minhas said. Women who gain a lot of weight during pregnancy may be at higher risk for developing preeclampsia.
The research focused on more than 8,500 women in the Boston area who were part of a broader study of pregnancy, infancy and child health. Some were at risk for preterm birth, which overlaps with preeclampsia. Black women made up nearly half of the study participants.
The researchers gave each woman a score based on how closely she stuck to a Mediterranean diet.
In all, 10% developed preeclampsia. But the study found that the risk was 22% lower among women who more closely followed a Mediterranean-style diet during pregnancy, and this reduction in risk was even greater among Black women who did so. Black women are at higher risk of developing preeclampsia.
"Black women with the greatest adherence to a Mediterranean diet had an even greater reduction of preeclampsia risk, which further supports the idea that this intervention might work across women of different racial and ethnic backgrounds," Minhas said.
She and her colleagues plan to continue combing the data to see how this eating style may lower preeclampsia risk. They also hope to conduct a randomized, controlled trial comparing the Mediterranean diet to another eating regimen among women at risk for preeclampsia.
There are very few preeclampsia treatments that are safe and also produce meaningful benefits. The only cure is to deliver the baby, which often results in preterm birth.
"This is one of the reasons we are excited about the results as the Mediterranean diet is beneficial and safe for mom and baby," Minhas said.
As of now, women at risk for preeclampsia are typically treated with baby aspirin and monitored closely. Researchers didn't track whether women in the study took daily aspirin.
The findings were published April 20 in the Journal of the American Heart Association.
Dr. Mitchell Kramer, chairman of obstetrics and gynecology at Huntington Hospital in Huntington, N.Y., reviewed the findings.
Preeclampsia is a major health issue among pregnant women in the United States, he said.
"It disproportionately affects women of color and disadvantaged socioeconomic background," Kramer said.
These women often don't follow a healthy, well-balanced eating regimen due to a lack of access or income and education about diet, he said.
"The obstetrical provider community has always felt that a healthy diet made up of fresh foods, low salt, fruits, vegetables, decreased red meat, nuts, legumes and healthy oils will benefit the pregnant woman and fetus, and this study supports the importance of encouraging pregnant women, especially this studied population, to adhere to this Mediterranean-style diet," Kramer said.
The American Heart Association has more about the Mediterranean Diet.
SOURCES: Anum Minhas, MD, chief cardiology fellow, and cardio-obstetrics and advanced imaging fellow, Johns Hopkins University, Baltimore; Mitchell Kramer, MD, chairman, obstetrics and gynecology, Huntington Hospital, Huntington, N.Y.; Journal of the American Heart Association, April 20, 2022