Effect of Premeal Pistachio Supplementation on Cardiometabolic Risk Factors among Asian Indian Adults with Prediabetes: A Randomized Controlled Trial

Background: Asian Indians are susceptible to developing type 2 diabetes at a lower age and often consume diets that are high in glycemic load and low in healthy fats.

Objectives: This study aimed to evaluate the effect of 30 g prebreakfast and 30 g predinner supplementation of pistachios for 12 wk on glycated hemoglobin (HbA1c), other glycemic markers, anthropometry, and lipid profile of Asian Indians with prediabetes.

Methods: In a 12-wk parallel arm, randomized controlled trial, we recruited 120 participants with prediabetes based on American Diabetes Association criteria. The intervention group (n = 60) consumed 60 g pistachios (30 g prebreakfast and predinner) whereas the control group (n = 60) followed a routine diet that excluded nuts. At baseline and 12 wk, we collected blood samples for biochemical analysis, anthropometrics, and 24-h recalls. Participants wore a continuous glucose monitoring (CGM) sensor during the trial's first and last 2 wk. Urinary N-methyl-trans-4-hydroxy-l-proline (MHP) was measured as a marker of pistachio consumption.

Results: A total of 109 participants completed the study (follow-up rate = 90.8%). Compared with participants in the control group, those in the intervention group had significant reductions in HbA1c (mean between-group difference: -0.2; 95% confidence interval: -0.3, -0.1; P < 0.001] with no significant changes in fasting or 2-h post glucose load plasma glucose. Compared with the control group, the intervention group had significant reductions in serum triglyceride, waist circumference, lipid accumulation product, visceral adiposity index, and atherogenic index. Urinary MHP (mg/g creatinine) showed a 62% increase in the intervention compared with the control group (P < 0.05). CGM data revealed significant decreases in the incremental area under the curve, 2-h after breakfast (28%, p=0.01) and after dinner (17%, P = 0.002) in the intervention group compared to the control group.

Conclusions: A 12-wk, premeal load of 60 g pistachios lowers HbA1c and improves cardiometabolic profile among Asian Indians with prediabetes. This is among the first studies to investigate these effects in this ethnic group. This study was registered in the Clinical Trial Registry of India as CTRI/2020/11/029340.