Glycemic Response of Pistachios – A Dose Response Study

Background: Nuts, related to their effects on plasma lipids, have beneficial effects on reducing coronary heart disease (CHD) risk. It was also recently demonstrated that different doses of mixed nuts consumed with white bread decreased postprandial glycemia in a dose dependant manner. However, the specific effects of pistachios on blood glucose have yet to be determined. Objective: To assess the acute glycemic effects of 3 different doses of pistachios consumed alone and co‐ingested with a carbohydrate meal. Methods: Ten healthy adult volunteers were fed 28g, 56g and 84g of pistachios alone or with 50g of available carbohydrate from white bread after an overnight fast. Capillary blood samples for glucose analysis were obtained over 2h, and glycemic responses were assessed by calculating the incremental area under the 2h curve (IAUC). Results: The glycemic responses of pistachios consumed alone were significantly lower (P<0.05) expressed as a percentage of 50g available carbohydrate from white bread (100%): 28g pistachios (6.3±1.9%); 56g (9.5±2.4%); and 84g (10.4±3.3%). The addition of pistachios to white bread resulted in a progressive reduction in the glycemic response (IAUC) of the composite meal in a dose‐dependent manner (pistachios: 28g [89.1±6.0]; 56g [67.3±9.8]; and 84g [51.5±7.5]). Conclusion: Pistachios, which contain 21% available carbohydrate, had a small effect on postprandial glycemia when consumed alone. However, pistachios reduced the postprandial glycemic impact of white bread with which they were eaten in a dose dependent manner. The suppression of the glycemic response of carbohydrate foods may be part of the mechanism by which pistachios and other nuts may reduce the risk for diabetes and CHD. Research Support: California Pistachio Commission