A cohort study of 8,507 racially and ethnically diverse US women revealed that a diet rich in vegetables, fruit, legumes, grains, dairy, and seafood reduced the risk of preeclampsia by more than 20%, with the biggest gains among black women.
Results provide valuable insight into the women most likely to benefit from dietary interventions to reduce the risk of preeclampsia, the researchers say.
Lead scientist, Anum S. Minhas commented that given the health hazard to mothers and children it is important to identify modifiable factors to prevent preeclampsia – and particularly among high-risk groups, such us black women.
"We were surprised that women who more frequently ate foods in the Mediterranean-style diet were significantly less likely to develop preeclampsia, with Black women experiencing the greatest reduction in risk.
"This is remarkable because there are very few interventions during pregnancy that are found to produce any meaningful benefit, and medical treatments during pregnancy must be approached cautiously to ensure the benefits outweigh the potential risks to the mother and the unborn child."
Associated risks
Preeclampsia is a condition that presents during pregnancy and characterised by severe high blood pressure, and liver and kidney damage. It affects around 5-10% of women globally, and especially in the presence of obesity and / or any form of diabetes.
Women with preeclampsia have an increased risk of long-term cardiovascular disease (CVD), ischemic stroke, heart failure, and pre-term birth. Children born to mothers with preeclampsia often have a low birth weight and also have an elevated risk of high blood pressure and CVD.
The condition can lead to major complications or even death for women and their unborn child.
Minhas said: "Women should be encouraged to follow a healthy lifestyle, including a nutritious diet and regular exercise, at all stages in life. Their health during pregnancy affects their future cardiovascular health and also impacts their baby's health."
Lack of diversity
Scientists believe the benefits of a Mediterranean-style diet (MSD) derive from improvements in oxidative stress or endothelial cell function, which could contribute to improved placental vascular function during pregnancy. MSD’s may also reduce the risk of preeclampsia through metabolomic changes.
Previous studies show that a Mediterranean diet improves microvascular function and endothelial function, and “result in a unique metabolic signature, which has been predictive of lower future CVD risk”.
The authors therefore hypothesize that adherence to a dietary pattern such as a MSD can reduce the risk of preeclampsia “given the shared risk factors between CVD, preterm birth, and preeclampsia”.
Given the lack of evidence on the link between MSD and preeclampsia in high-risk women, researchers focused on a broad demographic of racially and ethnically diverse women.
Study protocol
Participants were recruited from Boston Medical Centre, which serves a predominantly urban, low-income, under-represented racial and ethnic population, and had an average age of 25 years.
Black women accounted for 47% of participants; a quarter were Hispanic women (28%), and the remaining were white or “other” race.
Dietary data for women enrolled in the 1998 to 2016 Boston Birth Cohort was examined along with self-reported information from postpartum questionnaires.
Researchers developed a Mediterranean-style diet score (MSDS) based on participants responses to food frequency interviews and postpartum questionnaires.
Findings
The analysis found that 10% of participants developed preeclampsia and this correlated with low conformity to a MSD.
Women with pre-pregnancy obesity, chronic hypertension, and any form of diabetes before pregnancy were twice as likely to develop preeclampsia compared to women without these conditions.
Black women had the lowest MSD scores and highest risk (78%) for preeclampsia compared to other participants who more closely adhered to the MSD however they also presented the greatest reduction in odds of developing the condition through adherence to the MSD.
While the study delivered some significant results, limitations - relating to postpartum food frequency interviews and self-reported questionnaires - suggest prospective studies are required to verify results that assess diet prior to diagnosis of preeclampsia, the authors conclude.
Source: Journal of the American Heart Association
Published online: DOI: 10.1161/JAHA.121.022589
‘Mediterranean-Style Diet and Risk of Preeclampsia by Race in the Boston Birth Cohort’
Authors: Anum Minhas et al.