http://www.nrjournal.com/article/S0271-5317%2815%2900181-5/abstract
Abstract
Epidemiological
studies indicate that habitual coffee consumption lowers the risk of
diabetes and cardiovascular diseases. Postprandial hyperglycemia is a
direct and independent risk factor for cardiovascular diseases. We
previously demonstrated that coffee polyphenol ingestion increased
secretion of Glucagon-like peptide 1 (GLP-1), which has been shown to
exhibit anti-diabetic and cardiovascular effects. We hypothesized coffee
polyphenol consumption may improve postprandial hyperglycemia and
vascular endothelial function by increasing GLP-1 release and/or
reducing oxidative stress. To examine this hypothesis, we conducted a
randomized, acute, crossover, intervention study in healthy male adults,
measuring blood parameters and flow-mediated dilation (FMD) after
ingestion of a meal with or without coffee polyphenol extract (CPE).
Nineteen subjects consumed a test meal with either a placebo- or
CPE-containing beverage. Blood biomarkers and FMD were measured at
fasting and up to 180 minutes postprandially. The CPE beverage led to a
significantly lower peak postprandial increase in blood glucose and
diacron-reactive oxygen metabolite, and significantly higher
postprandial FMD than the placebo beverage. Postprandial blood GLP-1
increase tended to be higher after ingestion of the CPE beverage,
compared with placebo. Subclass analysis revealed that the CPE beverage
significantly improved postprandial blood GLP-1 response and reduced
blood glucose increase in the subjects with a lower insulinogenic index.
Correlation analysis showed postprandial FMD was negatively associated
with blood glucose increase after ingestion of the CPE beverage. In
conclusion, these results suggest that coffee polyphenol consumption
improves postprandial hyperglycemia and vascular endothelial function,
which is associated with increased GLP-1 secretion and decreased
oxidative stress in healthy humans.
