Peanuts or an Isocaloric Lower Fat, Higher Carbohydrate Nighttime Snack Have Similar Effects on Fasting Glucose in Adults with Elevated Fasting Glucose Concentrations: a 6-Week Randomized Crossover Trial

Background The glycemic effects of peanuts are not well studied and no trials have been conducted in adults with elevated fasting plasma glucose (FPG). Furthermore, intake of peanuts as a nighttime snack, an eating occasion affecting FPG, has not been examined. Objectives The aim was to determine the effect of consuming 28 g/d of peanuts as a nighttime snack for 6 wk on glycemic control and cardiovascular disease risk factors, compared with an isocaloric lower fat, higher carbohydrate (LFHC) snack (whole grain crackers and low-fat cheese), in adults with elevated FPG. Methods In a randomized crossover trial, 50 adults (FPG 100 ± 8 mg/dL) consumed dry roasted, unsalted peanuts [164 kcal; 11% energy (E) carbohydrate, 17% E protein, and 73% E fat] or a LFHC snack (164 kcal; 54% E carbohydrate, 17% E protein, and 33% E fat) in the evening (after dinner and before bedtime) for 6 wk with a 4-wk washout period. Primary (FPG) and secondary end points [Healthy Eating Index-2015 (HEI-2015), weight, insulin, fructosamine, lipids/lipoproteins, central and peripheral blood pressure, and pulse wave velocity] were evaluated at the beginning and end of each condition. Linear mixed models were used for data analysis. Results FPG was not different between the peanut and LFHC conditions (end point mean difference: −0.6 mg/dL; 95% CI: −2.7, 1.6; P = 0.67). There were no between-condition effects for secondary cardiometabolic endpoints. The HEI-2015 score was not different between the conditions (3.6 points; P = 0.19), although the seafood/plant protein (2.0 points; P < 0.01) and added sugar (0.8 points; P = 0.04) components were improved following peanut intake. The whole grain component was lower with peanuts compared with LFHC (−2.6 points; P < 0.01). Conclusions In adults with elevated FPG, peanuts as a nighttime snack (28 g/d) did not affect FPG compared with an isocaloric LFHC snack after 6 wk. This trial was registered at clinicaltrials.gov as NCT03654651.