A randomized clinical trial has demonstrated that a modified version of the Dietary Approaches to Stop Hypertension (DASH) diet specifically tailored for diabetes can significantly reduce blood pressure in adults with type 2 diabetes, even among those already taking multiple antihypertensive medications.
The study, published in JAMA Internal Medicine, tested the DASH4D (DASH For Diabetes) diet in 85 participants with type 2 diabetes. Results showed that the low-sodium DASH4D diet reduced systolic blood pressure by 4.6 mm Hg and diastolic blood pressure by 2.3 mm Hg compared with a typical US diet with higher sodium content.
Clinical Trial Design and Methodology
The DASH4D study was conducted from June 2021 to June 2024 at a community-based study center. Participants had systolic blood pressure between 120 and 159 mm Hg and diastolic blood pressure below 100 mm Hg. Each participant underwent four dietary interventions in random order, each lasting five weeks: DASH4D with lower sodium, DASH4D with higher sodium, typical US diet with lower sodium, and typical US diet with higher sodium.
"Most people in this study were taking more than one blood pressure medication, but we found that you can lower it further with dietary change," said Dr. Lawrence Appel, senior researcher and professor of medicine at Johns Hopkins University School of Medicine. "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."
Diabetes-Specific Dietary Modifications
The DASH4D diet maintains the original DASH diet's emphasis on fruits, vegetables, and low-fat dairy while reducing saturated fat and cholesterol intake. However, it incorporates several modifications specifically for diabetes management:
- Lower carbohydrate content to help maintain stable blood sugar levels
- Increased intake of unsaturated fats
- Reduced potassium intake to help prevent kidney disease that often accompanies type 2 diabetes
"The DASH diet has been around for a long time, and is part of the standard treatment for hypertension," said lead researcher Dr. Scott Pilla, an assistant professor of medicine at Johns Hopkins University School of Medicine. However, he noted there had been little study of this diet in people with diabetes, particularly with sodium modifications.
Cardiovascular Risk Reduction
The five-point reduction in systolic blood pressure achieved by the low-sodium DASH4D diet translates to meaningful cardiovascular risk reductions. According to the study results, this reduction decreased the risk of stroke by 14%, heart failure by 8%, and overall heart health events by 6%.
For context, blood pressure medications typically lower systolic blood pressure by about 10 points, making the dietary intervention's five-point reduction clinically significant, especially as an adjunct to existing pharmacological treatments.
Study Population and Adherence
Approximately 66% of study participants were taking two or more high blood pressure medications, demonstrating that dietary interventions can provide additional benefits beyond standard pharmacological treatment. The study achieved high adherence rates, with participants provided all meals and instructed to consume no outside food while maintaining constant weight throughout the study period.
Most of the blood pressure reduction occurred within the first three weeks of each diet period, and adverse events were rare across all dietary interventions.
Clinical and Public Health Implications
The researchers emphasized the broader implications of their findings. "The findings in DASH4D have public health implications," they wrote, noting that the results provide evidence of blood pressure lowering efficacy through dietary change in people with type 2 diabetes, including those treated with multiple medications.
The study particularly highlighted the importance of dietary sodium reduction in type 2 diabetes management, with sodium reduction appearing to have a stronger impact on lowering blood pressure than the DASH4D diet composition alone.
Future Implementation Challenges
Despite the promising results, researchers acknowledged implementation challenges. "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 so they can integrate them into their daily life and make them part of their daily routine," Pilla said.
The study was conducted at a single center with a less diverse population than originally planned, though it did include a significant number of Black participants, a group at higher risk for hypertension-related complications. The COVID-19 pandemic also posed challenges by interrupting participant feeding at various points during the trial.
