A modified Dietary Approaches to Stop Hypertension (DASH) diet, tailored for individuals with type 2 diabetes (T2D), has been shown to substantially improve glycaemic control and increase time in range (TIR), according to findings from the randomised DASH4D trial.¹

The DASH diet is well-established for its benefits in managing hypertension, but its impact on key glycaemic metrics in T2D has been less rigorously studied. This trial, DASH4D (NCT04286555), aimed to assess the effects of a DASH-style diet on glucose levels using continuous glucose monitoring (CGM).

The study was a randomised, crossover feeding trial involving 89 participants with T2D. Each participant consumed four distinct isocaloric diets in a random order, with each feeding period lasting 5 weeks. The interventions consisted of the DASH4D diet (a DASH-style diet tailored for diabetes) or a comparison diet reflecting a typical American intake. Each of these two diets was provided with both a higher sodium level (3,700 mg/day at 2,000 kcal) and a lower sodium level (1,500 mg/day at 2,000 kcal).¹˒²

The primary outcomes, assessed over 14 days of CGM during each period, were mean glucose, the percentage of TIR (defined as 3.9–10.0 mmol/L or 70–180 mg/dl), and the coefficient of variation (CV). Secondary outcomes included glucose standard deviation (SD) and time spent in hyperglycaemia or hypoglycaemia.¹

Compared with the typical American diet, the DASH4D diet resulted in a significant reduction in mean glucose, with a mean difference of -0.62 mmol/L (-11.1 mg/dl; p<0.001). Participants on the DASH4D diet also spent more time in the target glycaemic range, with TIR increasing by 5.2 percentage points (p<0.001). There was no significant effect on the glucose CV (p=0.52).¹

Analysis of secondary outcomes revealed that the DASH4D diet was associated with a lower glucose SD and reduced time spent in hyperglycaemia (glucose >10.0 mmol/L and >13.9 mmol/L). Importantly, the time spent in hypoglycaemia (glucose <3.9 mmol/L and <3.0 mmol/L) was similar across all diets, indicating no increased risk of low blood sugar with the intervention. No serious adverse events related to the study diets or CGM use were reported.¹

These findings provide strong evidence that a structured nutritional intervention can be a highly effective strategy for managing T2D. The authors concluded that "the DASH4D diet is a promising nutritional approach to substantially improve glycaemic control in adults with type 2 diabetes."¹ The ability of the diet to improve key CGM metrics like mean glucose and TIR, without increasing hypoglycaemia risk, positions it as a valuable non-pharmacological tool for healthcare professionals to recommend to their patients.

References

1.  Fang, M., Wang, D., Rebholz, C.M. et al. DASH4D diet for glycemic control and glucose variability in type 2 diabetes: a randomized crossover trial. Nat Med (2025). https://doi.org/10.1038/s41591-025-03823-3

2.  Pilla, S. J. et al. Dietary patterns, sodium reduction, and blood pressure in type 2 diabetes: The DASH4D Randomized Clinical Trial. JAMA Intern Med. (2025). https://doi.org/10.1001/jamainternmed.2025.1580

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