DASH diet transformed: New research unveils diabetes-fighting variation

Researchers in a recent clinical trial have found that modifying the popular DASH (Dietary Approaches to Stop Hypertension) diet, which is known to lower blood pressure, can also lower glucose in adults with type 2 diabetes.

Developed in the mid-1990s, research on the DASH diet was funded by the US National Institutes of Health to address high blood pressure in the general population. It focuses on fruits, vegetables, and low-fat dairy products, and is low in saturated fat and cholesterol.

A research team led by the Johns Hopkins Bloomberg School of Public Health, US, modified the diet for people with type 2 diabetes. The rebranded “DASH for Diabetes” diet — or “DASH4D” — mirrors the DASH diet but is lower in carbohydrates and higher in unsaturated fats.

The DASH4D diet also has reduced potassium levels in the DASH4D diet to improve safety for individuals with chronic kidney disease.

“The original DASH diet has long been recommended for people with diabetes and other health conditions due to its effectiveness in lowering blood pressure, but this is the first time a controlled study has shown a significant improvement in glucose control as well,” says study senior author Elizabeth Selvin, Ph.D., MPH, director of the Welch Center for Prevention, Epidemiology and Clinical Research and professor in the Bloomberg School’s Department of Epidemiology, US.

Better control of glucose levels

The study published in Nature Medicine examined 89 participants with type 2 diabetes. Researchers fed them prepared meals at a clinical research center for 20 weeks, half of the time on the DASH4D diet and half on a standard diet modeled after what US adults typically eat.

The participants’ blood glucose levels were measured using wearable continuous glucose monitoring (CGM) devices.

When participants consumed the DASH4D diet, they exhibited a clinically meaningful reduction of average blood glucose levels. Those who stuck to the DASH4D diet had blood sugar levels that were 11 mg/dL lower on average than when eating the standard diet.

Participants on the DASH4D diet exhibited a clinically meaningful reduction of average blood glucose levels.They also stayed in the optimal blood glucose range for an extra 75 minutes a day.

Both effects are considered clinically meaningful as the researchers say they may lower risks of heart disease, kidney disease, and other long-term adverse consequences of diabetes.

“Larger improvements were seen in participants who had higher blood glucose levels at the start of the trial,” says Michael Fang, PhD, MHS, an assistant professor also in the Bloomberg School’s Department of Epidemiology.

“For those with the highest glucose levels — HbA1c above 8% — the DASH4D diet increased their time in the optimal blood glucose range by about three hours per day — a very significant benefit.”

Effects on lowering blood pressure

According to the Centers for Disease Control and Prevention, an estimated 35 million Americans have type 2 diabetes.

The “DASH4D CGM” study, led by Selvin, was part of a larger Hopkins-led clinical trial, published this spring. The main trial found the DASH4D diet also lowered blood pressure among individuals with type 2 diabetes.

Among the 89 people who completed the DASH4D CGM study, 67% were female and 88% were African American. Trained staff prepared meals — eventually totaling more than 40,000 — for participants at a central testing site during the 2021–2024 study period.

In random order, each participant spent five weeks on a low-sodium DASH4D diet, five weeks on a high-sodium DASH4D diet, and five weeks each on low-sodium and high-sodium standard diets. Sodium levels differed in order to test the effects of sodium on hypertension.

Participants wore CGM devices during weeks three and four in every five-week diet period. All the diets had the same number of calories.

“This trial design is what we call a ‘crossover’ design — we compared participants with themselves under different diet conditions, which reduced inter-individual variability and enhanced statistical power, allowing us to detect meaningful treatment effects despite what might initially appear to be small sample size,” Selvin explains.

For participants on the DASH4D diet, blood glucose levels were also less variable generally, and did not enter the hypoglycemic range more often than for the standard diets.

“We’re encouraged by these results and believe this can make a major impact on population health,” says Fang. “The DASH4D diet was specifically designed to be sustainable and easy to follow.”

Dieting for diabetes intervention

In recent research, French fries were linked to a higher risk of developing type 2 diabetes in a Harvard paper. The study examines how different styles of preparing potatoes may influence diabetes risk, suggesting that replacing any kind of potato with whole grains leads to a greater health benefit.

Another study found that consuming one artificially sweetened soft drink each day could raise a person’s risk of developing type 2 diabetes by 38%. The paper suggests this risk could be higher than it is for consumers of sugar-sweetened beverages, such as regular sodas, where the threat was said to be 23% greater.

In other research, scientists discovered a molecule, D-lactate, created by gut bacteria, enters the bloodstream to fuel the liver to make more glucose and fat than needed. This finding may open new pathways to improve blood sugar levels and reduce liver damage when treating metabolic diseases like type 2 diabetes and fatty liver disease.