Abstract Body: Background: In a recent controlled feeding trial, we showed that a DASH-style diet tailored for individuals with type 2 diabetes (DASH4D diet) improved short-term glycemic control assessed by continuous glucose monitoring. In this secondary analysis of the trial, we examined the effect of the DASH4D diet on biomarkers of glycemia.
Methods: In the DASH4D trial, adults with type 2 diabetes were fed four isocaloric diets in a random order: DASH4D diet or comparison diet (representative of a typical American diet), each with higher or lower sodium. Each feeding period lasted 5 weeks and was separated by ≥1 week break. The primary outcome in this analysis was fructosamine, a marker reflecting glycemia over the past 2-3 weeks. Secondary outcomes included fasting glucose (reflecting glycemia at a single moment) and HbA1c (reflecting glycemia over 2-3 months). Outcomes were assessed at the end of each feeding period. Using an intention-to-treat approach, we estimated the effect of the DASH4D (versus comparison) diet on all outcomes with linear mixed effect models. In exploratory analyses, we examined the effect of the DASH4D diet by baseline HbA1c.
Results: We included 101 participants (mean age: 67 years; 65% female; 88% Black adults). At baseline, mean HbA1c was 7.0% and 55% of participants were using two or more glucose-lowering medications. Compared to the comparison diet, the DASH4D diet significantly reduced end-of-period fructosamine (adjusted difference: -5.6 umol/L, P<0.002) and fasting glucose (adjusted difference: -4.5 mg/dL; P=0.019) (Figure A1-A2). The DASH4D diet also had a small effect on HbA1c (adjusted difference: -0.09 %-points; P=0.035) (Figure A3); however, the 5-week duration of the feeding periods was suboptimal for estimating the effect of the diets on HbA1c. The effect of the DASH4D diet on fructosamine and fasting glucose was larger for participants with higher baseline HbA1c (Figure B1-B3).
Conclusion: The DASH4D diet significantly lowered fructosamine and fasting glucose in adults with type 2 diabetes. These results support the inclusion of the DASH4D dietary pattern into policy and clinical guidelines to improve glycemic control in type 2 diabetes.