Study Shows Proper Diet Could Reduce Cardiovascular Risk by 10% or More

Stephen Juraschek, MD, PhD

Data from the DASH trial provides evidence demonstrating adherence to a healthy diet can reduce cardiovascular disease risk by 10% in adult patients.

An analysis of data from the landmark trial led by investigators at Beth Israel Deaconess Medical Center (BIDMC), results of the study suggest adherence to the DASH diet was associated with a 10.3% reduction in 10-year ASCVD risk and adherence to the fruit and vegetable diet was associated with a 9.9% reduction in 10-year risk compared to the Western diet over an 8-week period, with these effects more apparent in women and Black adults.

"While physicians and patients rely on the extensive data available when choosing appropriate pharmacologic therapy to prevent atherosclerotic cardiovascular disease, there's limited evidence to inform expectations for risk reductions from established lifestyle interventions," said study investigator Stephen P. Jurashcek, MD, PhD, a clinician-researcher in the Department of Medicine at BIDMC, in a statement from BIDMC. "Our study suggests that the benefits associated with these diets may vary by sex and race. While a diet rich in fruits and vegetables produced reductions in risk for woman and Black participants, the effect with the DASH diet was twice as large in women and 4 times as large in Black adults."

As a result of the limited evidence related to nutrition and cardiovascular health, the NHLBI-sponsored Dietary Approaches to Stop Hypertension (DASH) trial was an endeavor launched in 1993 with the aim of evaluating the effects of different dietary approaches for lowering blood pressure. With randomization beginning in 1994, the multicenter trial randomized patients to 1 of 3 dietary approaches: a typical “Western” diet, a diet heavy in fruit and vegetables, or the DASH diet, which was characterized as being high in fruits, vegetables, and low-fat dairy products, and had a favorable macronutrient profile.

Published in the New England Journal of Medicine in 1997, the original article demonstrated adherence to the DASH diet reduced systolic and diastolic blood pressure by 5.5 and 3.0 mmHg more, respectively, than the control diet (P <.001 for each). Results also indicated adherence to the fruits and vegetables diet was associated with a systolic blood pressure reduction 2.8 mmHg greater (P <.001) and diastolic blood pressure reduction 1.1 mmHg greater (P=.07) than the control diet.

In the current analysis, investigators leveraged data from the trial to determine the effects of each approach on 10-year ASCVD risk score using information related to blood pressure and lipid measurements before and after the 8-week intervention period.

Upon analysis, results indicated adherence to the DASH diet during the trial was associated with a -10.3% (95% CI, -14.4 to -5.9) reduction in 10-year ASCVD risk score, with this effect more pronounced in women and Black adults. Adherence to the fruits and vegetables diet was associated with a -9.9% (95% CI, -14.0 to -5.5) reduction in 10-year ASCVD risk score, with the trend of a more pronounced effect seen in women and Black adults also observed among this cohort. Comparisons of the DASH diet against the fruits and vegetable diet demonstrated there were no significant differences between the approaches (-0.4% [95% CI, -6.9 to 6.5]).

Further analysis suggested the reductions in risk observed attributable to the difference in systolic blood pressure alone, relative to the control diet, were -14.6% (95% CI, -17.3 to -11.7) with the DASH diet and -7.9% (95% CI, -10.9 to -4.8) with the fruits and vegetables diet, with a net relative advantage of 7.2% greater relative reduction favoring the DASH diet compared to the fruits and vegetables diet. However, investigators pointed out this reduction was offset by the impact of the DASH diet on high-density lipoprotein, which increased 10-year risk score by 8.8% (95% CI, 5.5 to 12.3) versus the more neutral effect of -1.9% (95% CI, -5.0 to 1.2) observed with the fruits and vegetables diet.

"The findings could have major implications for clinical practitioners and policy makers alike," said lead investigator Sun Young Jeong, MD, MPH, an internal medicine resident at BIDMC, in the aforementioned statement. "Cardiovascular disease is the leading cause of death in women and hypertension is also more strongly linked with heart failure and death in women than men. We also know women are less likely to receive risk factor modification therapies, such as statins, so our finding that DASH may be more efficacious among women are relevant for lifestyle counseling in this group."

This study, “Effects of Diet on 10-Year Atherosclerotic Cardiovascular Disease Risk (from the DASH Trial),” was published in the American Journal of Cardiology.