Acute effect of pistachios on postprandial endothelial function: Influence of fat quantity and quality

Abstract

Previous studies have shown that saturated fat and refined carbohydrates (CHO) acutely impair endothelial function, while unsaturated fats appear to exert a neutral effect. The purpose of this study was to examine endothelial function after meals differing in fat and CHO content. We assessed endothelial function in 20 adults with metabolic syndrome before and after each of the following meals: pistachios alone, pistachios plus white bread, white bread alone (12 and 50 g available CHO), and white bread plus cheese and butter. Endothelial function was assessed via pulse wave amplitude (EndoPAT) and reported as reactive hyperemia index (RHI). Fasting RHI did not differ among treatments, and the primary analysis examined change in RHI from fasting up to 3 hours postprandially. RHI was differentially affected by the meals (p=0.01). RHI decreased after the white bread plus cheese and butter meal (−0.09±0.09) and increased after the white bread only meals (0.17±0.09 and 0.15±0.09 for white bread 12g and 50g, respectively); this differential response was statistically significant (Tukey p<0.05). An intermediate change in RHI was observed after the pistachio meals (0.05±0.09 and −0.03±0.09 for pistachio and pistachio plus white bread, respectively). These results provide further evidence that endothelial function is differentially affected by type and quantity of dietary fat.Funding: American Pistachio Growers