High-dose resveratrol supplementation had virtually no physiological effect on obese men participating in a small, 1-month study conducted in Denmark.It certainly does.
The findings were published online November 28 in Diabetes by Morton M. Poulsen, an MD/PhD student from the Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark, and colleagues.
The polyphenolic compound resveratrol, a component of grapes and wine as well as other plants, has garnered attention in recent years for its potential health benefits. In rodent studies, resveratrol has appeared to mimic the protective metabolic effects of calorie restriction, including improved glucose metabolism and reduced inflammation.
Human data have been limited, however. "The present study does not support the use of resveratrol in a human clinical setting, but before ultimately defining the role of resveratrol in human metabolism, additional studies are strongly required," Poulsen told Medscape Medical News.
A total of 26 obese but otherwise healthy men were enrolled in the randomized, placebo-controlled, double-blinded, and parallel-group design study; 24 completed 4 weeks of treatment with either resveratrol or placebo.
The study dose, 500 mg trans-resveratrol 3 times daily, was 10 times higher than that used in a previous randomized study by Timmers et al, which did find improved metabolic parameters among 11 healthy obese men.
"Intuitively this should improve our possibility of observing an effect, which is, however, not the case," Poulsen said.
At 4 weeks, no significant differences between the resveratrol and placebo groups were seen in the primary outcome measure (insulin sensitivity, as assessed by the hyperinsulinemic euglycemic clamp technique). Insulin levels increased insignificantly in both groups.
There was also no effect of resveratrol on hemoglobin A1c levels; total, high-density lipoprotein, or low-density lipoprotein cholesterol levels; triglycerides; inflammatory biomarkers; leptin; or liver function tests. Measures of energy expenditure did not differ between the groups, nor did measures of c-peptide, glucagon, cortisol, adiponectin, and free fatty acids.
Resveratrol slightly increased both systolic and diastolic blood pressures, but the difference with placebo was nonsignificant. Measures of body composition also did not differ between the groups, nor did measures of ectopic or visceral fat content, Poulsen and colleagues report.
"The lack of effect disagrees with persuasive data obtained from rodent models and raises doubt about the justification of resveratrol as a human nutritional supplement in metabolic disorders," Poulsen and colleagues write.
But have no fear, Whore Foods will continue to sell it.