A daily 320 milligram dose of anthocyanins, equivalent to about 100 g of fresh blueberries and blackcurrants, was associated with an 8% reduction in LDL cholesterol, a 23% reduction in triglycerides, and a 19% increase in HDL cholesterol, report scientists from Guangdong Provincial Key Laboratory of Food, Nutrition, and Health and Sun Yat-sen University.
In addition, anthocyanin supplementation for 24 weeks was associated with an 8.5% reduction in fasting plasma glucose and a 13% reduction in insulin resistance estimated using the homeostasis model (HOMA-IR).
Adiponectin, a hormone released from fat cells that plays an important role in the regulation of insulin sensitivity and energy, were increased following anthocyanin supplementation, with average increases of 23% reported, compared to placebo.
“These data extend findings that so far have been observed only in cell and rodent models to humans, showing that anthocyanin has the potential to improve metabolic health in subjects at risk of developing diabetes and metabolic syndrome,” wrote the researchers in the Journal of Nutrition.
Oxidative stress and diabetes
Type 2 diabetes is associated with a number of metabolic irregularities, including abnormal blood lipid levels (dyslipidemia), elevated triglyceride levels, and elevated blood sugar levels that lead to increases in oxidative stress.
In order to assess if anthocyanins, antioxidant compounds from berries, could produce benefits in humans, the Chinese researchers recruited 58 diabetics to participate in their 24 week randomized, placebo-controlled, double-blind trial. The participants were randomly assigned to receive either 320 mg per day of anthocyanins or placebo.
Results showed significant improvements in LDL and HDL cholesterol levels, as well as for triglycerides and other blood lipid markers.
“To put this into perspective, it was reported that the rate of cardiovascular disease events is reduced by nearly 1% for each 1% reduction in LDL cholesterol and by [greater or equal than] 1% for each 1% increase in HDL cholesterol,” wrote the researchers. “Therefore, the 7.9% decrease in LDL cholesterol and the 19.4% increase in HDL cholesterol observed in the present study would result in a nearly 27.3% reduction in coronary artery disease risk.”
Significant reductions in markers of oxidative stress, such as 8-iso-prostaglandin F2alpha, 13-hydroxyoctadecadienoic acid (13-HODE), and carbonylated proteins, were also observed in the anthocyanin group, compared with placebo.
Safe and efficacious
“We demonstrate beneficial effects of anthocyanin supplementation on metabolic disorders in subjects with type 2 diabetes,” wrote the researchers. “The protective mechanism by anthocyanin on diabetes was closely correlated with prevention of dyslipidemia, lower systemic oxidative damage, and an increase in insulin sensitivity.
“Furthermore, there were no effects and no adverse events were reported.
“Therefore, anthocyanin supplementation has the potential to overcome the metabolic aberrations that are associated with diabetes in humans.”
Source: Journal of Nutrition
Published online ahead of print, doi:10.3945/jn.114.205674
“Purified Anthocyanin Supplementation Reduces Dyslipidemia, Enhances Antioxidant Capacity, and Prevents Insulin Resistance in Diabetic Patients”
Authors: D. Li, Y. Zhang, Y. Liu, R. Sun, M. Xia
LDL cholesterol and trigylceride levels were decreased by 8% and 23%, respectively, while HDL levels increased by 19%