Intake of pistachios as a nighttime snack has similar effects on short and longer-term glycemic control compared to education to consume 1-2 carbohydrate exchanges in adults with prediabetes: A 12-week randomized crossover trial

BACKGROUND:Nut intake is associated with better glycemic control and lower cardiovascular disease (CVD) risk. It remains unclear if nut intake timing affects glycemic control and CVD risk factors. Intake of pistachios as a nighttime snack may attenuate morning glucose production and lower fasting plasma glucose (FPG). OBJECTIVES:We assessed the effects of a nighttime (after dinner and before bedtime) pistachio snack (57 g/d) on glycemic control markers, vascular health, lipids/lipoproteins, and diet quality versus education to consume 1-2 carbohydrate (CHO) exchanges (usual care) in individuals with prediabetes. METHODS:A 2-period, randomized crossover trial was conducted. Participants were provided 57 g/d of dry roasted unsalted pistachios (319 kcal; fat 26 g; CHO 16 g; protein 12 g; fiber 6 g) as a nighttime snack or received usual care for 12 weeks. Primary [FPG] and secondary outcomes [hemoglobin A1c (HbA1c), insulin, HOMA-IR, lipids/lipoproteins, vascular health, and Healthy Eating Index-2015 (HEI-2015)] were measured before and after each condition. RESULTS:66 participants (50.9±11.6 years, FPG 106.2±6.4 mg/dL) were randomized, and 51 participants completed the trial. No between-condition differences in FPG (0.9 mg/dL [95% CI: -1.2, 3.1]), HbA1c, insulin, HOMA-IR, lipids/lipoproteins, blood pressure, or vascular health were observed. HEI-2015 score was higher after pistachio (6.8 points [95% CI: 1.5, 12.1]) vs. usual care driven by higher component scores for seafood and plant proteins (2.0 points [95% CI: 1.0, 2.9]), refined grains (2.3 points [95% CI: 1.1, 3.5]), and the fatty acid ratio (1.7 points [95% CI: 0.0, 3.5]). CONCLUSIONS:In adults with prediabetes, consuming 57 g/d of pistachios as a nighttime snack increased diet quality but had similar effects on glycemic markers, lipids/lipoproteins, blood pressure, and vascular health compared to the usual care control. Pistachios may be a healthful alternative to carbohydrate-rich nighttime snacks to increase alignment with Dietary Guidelines for Americans. CLINICALTRIALS:gov Identifier: NCT04056208.