Diet Prescribed To Lower Blood Pressure Also Reduces Women's Risk Of Heart Failure

"High blood pressure is always of concern because it has the potential to lead to major adverse events, including strokes, heart attacks and heart failure," explains senior author Emily Levitan, ScD, a research fellow in the Cardiovascular Epidemiology Research Center at BIDMC. She and her coauthors, therefore, hypothesized that the DASH diet (short for Dietary Approaches to Stop Hypertension) would also reduce a woman's risk of heart failure through its blood pressure lowering effects as well as its secondary effects on cholesterol and other heart-disease risk factors. The DASH diet, which has been shown to lower blood pressure in randomized clinical studies, is plentiful in fruits, vegetables, low-fat dairy products and whole grains. "These foods are high in potassium, magnesium, calcium and fiber, moderately high in protein, and low in saturated fat and total fat," explains Levitan.

A life-threatening condition that develops when the heart can no longer pump enough blood to meet the body's needs, heart failure (also known as congestive heart failure) is usually caused by existing cardiac conditions, including high blood pressure and coronary artery disease. Heart failure is the leading cause of hospitalization among patients 65 and older, and is characterized by such symptoms as fatigue and weakness, difficulty walking, rapid or irregular heartbeat, and persistent cough or wheezing.

Levitan analyzed data from women participants in the Swedish Mammography Cohort, in which women aged 48 to 83 who had no evidence of heart failure were invited to participate. In the fall of 1997, 36,019 women completed food frequency questionnaires to determine how closely their diets matched the DASH guidelines. Each participant was given a "score" based on their diet's similarity to the DASH diet.

"We then used records from the Swedish national healthcare system to determine whether the women went on to be hospitalized or to die from heart failure," explains Levitan. "We compared women with diets most similar to the DASH diet to women with diets that were not similar and found that those women whose diets most closely resembled DASH had the lowest risk of heart failure."

Their analysis showed that during the seven-year follow-up, 443 women developed heart failure, including 415 who were hospitalized and 28 women who died of the condition. Compared with the one-quarter of women with the lowest DASH diet scores, the one-quarter of the women with the highest DASH diet scores had a 37 percent lower risk of heart failure after factors such as age, physical activity and smoking were taken into account. More dramatically, the women with DASH scores in the top 10 percent had fully half the rate of heart failure compared with the one-quarter of participants with the lowest scores.

Of particular note, adds Levitan, a woman's diet did not have to precisely mimic the DASH diet in order to be of benefit. "Very few of the women we looked at had diets that shared all aspects of the DASH diet," she adds. "But we found that the closer they were, the lower their risk of heart failure. This suggests that making even moderate adjustments to your diet to include more fruits, vegetables, whole grains and low-fat dairy products, and less salt and sugar and less red meat and processed meats, can help improve cardiac health."

This study was supported by grants from the National Institutes of Health and from the Swedish Foundation for International Cooperation in Research and Higher Education.

Study coauthors include Murray Mittleman, MD, DrPH of BIDMC's Cardiovascular Epidemiology Research Unit and Alicja Wolk, DrMedSci, of Karolinska Institute, Sweden.