Special Diets

• By Maureen Williams, ND

Antioxidant Resveratrol for Better Blood Sugar Control

Resveratrol—a colorful antioxidant found in red wine, grapes, peanuts, chocolate, and several other foods—has received plenty of recent attention, as previous research has found that it supports heart health. A preliminary study has also found that taking resveratrol led to improved blood sugar control, insulin sensitivity, and blood vessel function in older people with high blood sugar levels.

The study, published in the Journal of Gerontology, included ten people over 65 whose fasting and after-meal blood sugar levels were higher than normal, but not high enough to be diagnosed with diabetes. They took 1 gram, 1.5 grams, or 2 grams of resveratrol per day for four weeks, while maintaining their usual diet and activity level. The study is considered preliminary because there was no placebo group.

Resveratrol is found in a number of healthy foods, which may also be high in fiber, essential fatty acids, and other antioxidants

Better blood sugar control after resveratrol

At the end of the study, fasting blood sugar levels remained unchanged, but several other signs of improvement were noted:

• Post-meal blood sugar levels were markedly reduced. This suggests that the participants had better blood sugar control.
• Post-meal insulin levels were also reduced. When considered along with the fact that blood sugar levels were also down, this indicates an increase in insulin sensitivity.
• There was a small but significant improvement in after-meal blood vessel function at the end of the study. This means blood vessels were better able to constrict and dilate in response to blood flow changes.

Early but promising findings

“Together, these results suggest that resveratrol shows promise as a new therapeutic strategy for an important and highly-prevalent metabolic disorder,” the study’s authors said. “This study provides the first evidence in humans that resveratrol may possess clinically relevant effects on glucose metabolism and vascular function.”

The researchers pointed out that their findings must be considered preliminary and need to be confirmed in placebo-controlled studies. They also noted that the study was too small to say whether there were different effects due to the different amounts of resveratrol used.

Eat your resveratrol

Resveratrol is found in a number of healthy foods, which may also be high in fiber, essential fatty acids, and other antioxidants that contribute to better insulin sensitivity, blood sugar maintenance, and vascular health. Here are some things to consider if you want to increase your resveratrol intake:

• Consider a supplement. The amounts of resveratrol used in this and other studies are as much as 1,000 to 2,000 times higher than you can get from eating reasonable amounts of these foods. So, if you want to use resveratrol as a treatment, talk to your doctor about whether a supplement is a better idea for you.
• Raise a glass of red wine. Red wine is the most concentrated source of resveratrol, and the longer the grape skins are left in during the fermentation process, the higher the resveratrol content. White wine has some, too, but much less.
• Choose grape juice. Red grape juice has about half as much resveratrol as red wine, but without the alcohol. If your blood sugar levels have been high, however, you’re better off avoiding all juices.
• Chew on some peanuts. Two ounces of peanuts is similar in resveratrol content to a fluid ounce of red wine. Sprouted peanuts have even more.
• Pour on the berries. Blueberries, bilberries, cranberries, and mulberries all have some resveratrol. Eat them raw—heating depletes their resveratrol.
• Enjoy some dark chocolate. Cocoa powder, baking chocolate, and dark chocolate provide small amounts of resveratrol. A small piece of dark chocolate is a nice treat, but pass on the more sugary chocolates if your blood sugar levels have been high.

(J Gerontol A Biol Sci Med Sci 2012;doi:10.1093/gerona/glr235)