Metabolic Effects of Bedtime Pistachio Consumption for 6 weeks in Overweight Persons

Abstract

Mono‐and polyunsaturated fats in nuts, such as pistachios (PI), may improve lipoprotein and glycemic status. Overweight persons trend for dyslipidemia and high diabetes risk. The lower limits of PI consumption required for health benefits are unknown. This study determined if PI at bedtime promotes beneficial changes in metabolic status in overweight persons. Overweight subjects (n=22; 55 ± 2 yrs; 90 ± 3.6 kg; BMI 31 ± 1) were randomized to 35.4 g PI self‐administered at bedtime or control (CO; no PI) for 6 weeks. There was no difference in physical activity level between subjects receiving PI and CO. Body weight was not different in PI and CO at wk 0, 1, 2, 4, and 6. HDL cholesterol at wk 0 and 6 in PI was 49.2 ± 3.5 to 50.3 ± 3.0, and CO was 60.8 ± 3.8 and 58.0 ± 2.7 mg/dL, at wk 6 PI had improved slightly relative to CO (P= 0.12). Plasma glucose at wk 0 and 6 in PI was 104.6 ± 2.8 and 99.6 ± 2.6 mg/dL, and CO was 102.0 ± 2.8 and 101.1 ± 2.6 mg/dL, at wk 6 PI had improved slightly relative to CO (P= 0.16). Plasma insulin at wk 0 and 6 in PI was 8.5 ± 1.0 and 8.4 ± 0.9, and CO was 7.2 ± 0.7 to 8.8 ± 0.7 μU/mL, at wk 6 PI had improved slightly relative to CO (P = 0.21). Beneficial changes in HDL, glucose, and insulin probably requires slightly more than 35.4 g/d PI for 6 wks. To increase the probability of metabolic health benefits, nutritionists may wish to encourage levels of daily PI consumption higher than those administered in this study.