Women with pregnancy-related diabetes (gestational diabetes) are at increased risk of developing high blood pressure later in life. However, a healthy diet may reduce the risk, according to key findings in a study published in the American Heart Association’s journal Hypertension, titled “Healthful Dietary Patterns and the Risk of Hypertension Among Women With a History of Gestational Diabetes Mellitus A Prospective Cohort Study.”
Hypertension is one of the most prevalent and preventable risk factors for cardiovascular and kidney diseases, and is one of the leading causes of death in the United States. Approximately 7 percent (ranging from 1 to 14 percent) of all pregnancies in the U.S. are complicated by gestational diabetes mellitus (GDM), a condition that is associated with an elevated risk for hypertension; but this risk can be modified with adherence to a healthy lifestyle, including diet and exercise.
The research team led by Cuilin Zhang from the Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, prospectively examined the associations between long-term adherence to three healthy diets and the subsequent risk of hypertension.
For the study, 3,818 women with a history of GDM were followed from 1989 to 2011, and grouped according to their diet — Dietary Approach to Stop Hypertension (also known as DASH diet), the alternative Mediterranean diet (aMED), and the Alternative Healthy Eating Index (AHEI). Researchers also assessed whether the associations were potentially mediated through changes in body mass index (BMI).
Incident hypertension was identified through self-administered questionnaires that women filled every four years. The adherence scores for AHEI 2010, aMED, and DASH were computed for each participant. The three diets share important similarities: eating fruits and vegetables, fish, legumes, and whole grains, while reducing red meat, salt, and processed meat.
During a median of 18.5 years of follow-up, the researchers documented 1,069 incident hypertension cases, meaning that women developed high blood pressure, which in turn increased their risk of having a heart attack or stroke.
The results showed that women who adhered to a healthy diet were 20 percent less likely to develop high blood pressure than those who did not. The researchers also found that an increase in BMI explained 20 to 30 percent of the relationship between lower healthy dietary pattern scores and an increased risk of hypertension.
“Our earlier research showed that diabetes in pregnancy increased a woman’s risk of developing hypertension, even 16 years after giving birth,” said Cuilin Zhang, M.D., Ph.D., senior study author and senior investigator at the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Rockville, Maryland, in a news release. “Our current study shows that a healthy diet, which has been proven to reduce high blood pressure risk in the general population, appears to be equally effective in reducing the risk in this group of high risk women.”
Women with a greater adherence to a healthy diet were less likely to be current smokers and more likely to drink alcohol moderately, to be more physically active, and to eat more cereal fiber. These women were also less likely to consume trans-fats.
Lower weight gain contributed to a reduced risk of developing high blood pressure in women who adhered to a healthy diet, and, regardless of weight gain or loss, a healthy diet was found to protect against high blood pressure.
“While the majority of these women’s glucose levels will return to normal after delivery, our study should serve as an early warning signal,” said Zhang, adding that pregnancy complications are normally treated by recommending women reduce their calorie intake and increase exercise.