DASH4D Diet Reduces BP by 4.6 mm Hg in Adults with T2D on Maximal Antihypertensive Therapy
For individuals with T2D, findings are more than numeric; a 5-mm Hg reduction in SBP reduces stroke risk by 14%, CV events by 6%, and heart failure by 8%, authors wrote.
A randomized controlled feeding study of 102 adults with type 2 diabetes (T2D) found that a modified DASH diet with reduced sodium lowered systolic blood pressure (SBP) by 4.6 mm Hg and diastolic blood pressure (DPB) by 2.3 mm Hg compared with a typical American diet with higher sodium, even among participants taking multiple antihypertensive medications.1
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The DASH4D (Dietary Approaches to Stop Hypertension for Diabetes) trial, published June 9 in JAMA Internal Medicine, is one of the largest controlled feeding studies conducted among people with T2D. Johns Hopkins Medicine researchers modified the original DASH diet by lowering carbohydrates, increasing unsaturated fat, and reducing potassium content to ensure safety for patients with chronic kidney disease.1
"The DASH diet has been around for a long time and is part of the standard treatment for hypertension. We know that it lowers blood pressure, but there has been little study of this diet and sodium reduction in people with diabetes," lead author Scott Pilla, MD, MHS, an assistant professor of medicine at the Johns Hopkins University School of Medicine, said in a statement from Johns Hopkins Medicine.2
The study used a randomized 4-period crossover design from June 2021 to June 2024. Participants consumed 4 diets in randomly assigned sequence for 5 weeks each: DASH4D with lower sodium, DASH4D with higher sodium, typical American diet with lower sodium, and typical American diet with higher sodium. Pitta and fellow researchers provided all food and adjusted calories to maintain stable weight.1
FINDINGS
Of the 102 participants, 85 (83.3%) completed all diet periods. The mean age was 66 years, 66% were women, and 87% self-identified as Black. Mean baseline blood pressure measured 135/75 mm Hg, and 66% of the cohort was using 2 or more antihypertensive medications at baseline. Compared with the typical American diet with higher sodium, the DASH4D diet with lower sodium reduced end-of-period SBP by 4.6 mmHg (95% CI, 7.2-2.0; P < .001) and DBP by 2.3 mmHg (95% CI, 3.7-0.9).1
Pitta et al reported that BP reduction occurred primarily during the first 3 weeks of each diet period, with sodium reduction appearing to contribute more than the DASH4D dietary pattern itself. Adverse events occurred infrequently across all diet periods, according to the study.1
"Most people in this study were taking more than one blood pressure medication, but we found that you can lower [BP] further with dietary change," corresponding author Lawrence Appel, MD, MPH, a professor of medicine at the Johns Hopkins University School of Medicine who helped develop the original DASH diet, said in the statement. "Blood pressure is one of the most important numbers to control because the higher the number, the higher the risk of stroke and heart disease."2
Study authors note that the clinical significance of the findings extend beyond numerical reduction. In people with diabetes, a 5-mm Hg reduction in SBP reduces stroke risk by 14%, cardiovascular events by 6%, and heart failure by 8%. Recent trials demonstrate that even a 3-mm Hg reduction in SBP is associated with approximately 12% reduction in stroke and total mortality.1
"Blood pressure is one of the most important numbers to control because the higher the number, the higher the risk of stroke and heart disease."
The study results address a critical gap in diabetes management. Four in 5 US adults with diabetes have hypertension, and hypertension contributes significantly to atherosclerotic cardiovascular disease, the leading cause of morbidity and mortality in people with diabetes. The evidence for dietary sodium reduction in management of hypertension is codified in current clinical guidelines that recommend the DASH diet with dietary sodium reduction, but to date the evidence has been limited.1
"A lot of people are interested in controlling diabetes and their blood pressure through diet and other lifestyle changes," Appel noted. The study provides evidence that dietary interventions effectively lower blood pressure in people with type 2 diabetes already receiving optimal medical therapy.2
However, implementation challenges remain. Sodium reduction to 1,500 mg per day proves difficult in the current food environment, requiring further research including community implementation studies.
"The next steps are to get the knowledge that we gained out to people with diabetes and help them use the diet to make healthy changes," Pilla said in the statement. "We need to make it easier for people to follow this diet in ways that are affordable and accessible to people of different cultures and with different dietary habits."2
