A double-blind study found that anthocyanins, antioxidants found in berries and other foods, can help improve metabolic symptoms in people with diabetes. Published in the Journal of Nutrition, the study divided 58 people with diabetes into two groups: one group received 160 mg of anthocyanins in supplement form twice daily for 24 weeks, while the other group received a placebo. The daily amount of anthocyanins (320 mg) was equivalent to eating approximately 3.5 ounces of fresh blueberries and black currants. The researchers found that:
Compared with the placebo group, those receiving anthocyanin supplements experienced a significant decrease in “bad” LDL cholesterol (-7.9%) and triglycerides (-23.0%), and an increase in “good” HDL cholesterol (+19.4%).
In addition, fasting blood glucose levels (-8.5%) and insulin resistance (-13.0%) decreased in the anthocyanin group.
Compared with the placebo group, markers of oxidative stress decreased significantly in the anthocyanin group. Oxidative stress is thought to play an important role in the development of diabetes.
This study was among the first to look at anthocyanin supplementation in people with diabetes, and more research is needed to confirm the benefits of anthocyanins. Nevertheless, the findings are of potential clinical significance, particularly for people with diabetes because of their increased risk for cardiovascular disease and events. For example, it is estimated that a 1% decrease in LDL cholesterol, or a 1% increase in HDL cholesterol, reduces the risk of cardiovascular events by 1%.