A lower sodium DASH-style diet reduced systolic blood pressure by 4.6 mm Hg in adults with type 2 diabetes, an effect primarily driven by sodium reduction rather than the DASH-style dietary pattern alone, according to a recent study. Compared with the higher sodium comparison diet, the DASH4D diet with lower sodium reduced systolic blood pressure by 4.6 mm Hg and diastolic blood pressure by 2.3 mm Hg. Within-diet comparisons showed that sodium reduction in the DASH4D diet alone lowered systolic blood pressure by 4.8 mm Hg, indicating that sodium intake played a larger role than diet pattern.
Methods
In a randomized clinical trial, researchers evaluated the effects of a Dietary Approaches to Stop Hypertension (DASH)–style diet tailored for type 2 diabetes (T2D), in combination with sodium reduction, on blood pressure (BP) among adults with T2D. The Dietary Approaches to Stop Hypertension for Diabetes (DASH4D) trial employed a 4-period crossover feeding design and was conducted at Johns Hopkins ProHealth Clinical Research Unit between June 2021 and June 2024.
The trial enrolled 102 adults with T2D, systolic blood pressure (SBP) ranging from 120 to 159 mm Hg, and diastolic blood pressure (DBP) of less than 100 mm Hg. Participants were randomized to consume four diet sequences, each for 5 weeks: (1) DASH4D diet with lower sodium, (2) DASH4D diet with higher sodium, (3) comparison (typical US) diet with lower sodium, and (4) comparison diet with higher sodium, which served as the reference. All food was provided, and participants' weight was maintained. The DASH4D diet was designed with lower carbohydrate intake, higher unsaturated fat, and moderated potassium content for safety in participants with chronic kidney disease.
The primary outcome was end-of-period SBP, with DBP as a secondary outcome. Both were measured across 5 days in each period using American Heart Association–standardized protocols. Among the 102 participants (mean age = 66 years; 66% women; 87% Black), 85 (83%) completed all diet periods.
Adherence exceeded 95% across all diets, and adverse events were infrequent. Lead author Scott J. Pilla, MD, MHS, of the Division of General Internal Medicine in the Department of Medicine at Johns Hopkins University School of Medicine in Baltimore, Maryland, wrote with coauthors: "A few participants experienced an SBP reading less than 90 mm Hg, which was more common with the lower sodium diets...Two participants consuming the DASH4D diet experienced confirmed hyperkalemia, with serum potassium levels of 5.5 mEq/L or greater, which was a small absolute risk compared with initiating angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Future research is needed to quantify the risks of the DASH4D diet and sodium reduction in higher-risk individuals, such as those with advanced kidney disease."
The researchers could not detect effects of the DASH4D diet and sodium reduction separately and the study population was not as diverse as they originally planned. COVID also interrupted participant feedings at several points, they noted.
"The observed effects on BP may contribute to a meaningful reduction in the risk of BP-related outcomes," the researchers concluded.
Full disclosures can be found in the published study.
Source: JAMA Internal Medicine
