Resveratrol Improves Insulin Sensitivity in Humans

Low-dose supplementation of resveratrol daily may reduce oxidative stress and improve the body's sensitivity to insulin, a study from University of Pecs in Hungary suggests.

In a double-blind, placebo-controlled study published in the British Journal of Nutrition, Hungarian researchers report observations that people with type 2 diabetes who take 5 milligrams of resveratrol twice daily improved their sensitivity to insulin after only our weeks.

"The present study shows for the first time that resveratrol improves insulin sensitivity, which might be due to a resveratrol-induced decrease in oxidative stress that leads to more efficient insulin signaling via the Akt pathway," the authors concluded.

The Akt pathway is a pathway involved in cellular uptake of glucose in response to insulin—it induces glucose transport, particularly into muscle cells. When working properly, insulin stimulates cells to take in glucose from the blood stream, thereby lowering circulating glucose levels and providing carbohydrate for the cells for energy production.

In this study, the researchers randomized 19 Caucasian male participants with type II diabetes into two groups. The intervention group received 5 milligrams of resveratrol, twice daily for four weeks. The control group received a placebo twice daily.

By the fourth week, the intervention group showed significantly reduced oxidative stress and increased levels of phosphroylated Akt, indicating improved insulin sensitivity. Similar studies also documented a glucose-lowering effect of resveratrol in diabetic rodents.

Resveratrol, a naturally occurring compound found in grapes and other foods, is also famed because of evidence as an anti-aging bioactive and an aid in weight management.

Reference

Brasnyo P, Molnar GA, Mohas M et al. Resveratrol improves insulin sensitivity, reduces oxidative stress and activates the Akt pathway in type 2 diabetic patients. Br J Nutr 2011;1-7.

Low muscle mass linked to diabetes

Being overweight is a risk factor for type 2 diabetes; however, a new study shows losing weight alone may not be enough to reduce risk of type 2 diabetes in people with low muscle mass and strength, particularly if they are over the age of 60.

These are the findings of new research from Dr. Preethi Srikanthan of University of California, Los Angeles, and colleagues who performed a cross-sectional analysis of 14,528 people from National Health and Nutrition Examination Survey III.

Dr. Srikanthan and colleagues concluded that age-related muscle loss, or sarcopenia, was associated with greater insulin resistance; and, sarcopenia, independent of obesity, may be an early predictor of diabetes. This association of sarcopenia and insulin resistance was strongest in those who were 60 years and older, the researchers warn.

Apart from these poor health outcomes, sarcopenia in older adults is also clearly associated with other health outcomes such as increased risk of falls, hip fractures, bone loss (osteopenia) and physical disability.
Several earlier studies suggest similarly that a direct correlation exists between sarcopenia in people ages 60 and older and greater risk of insulin resistance, metabolic syndrome, type 2 diabetes and cardiovascular disease, regardless of body weight.

Study Reference: Srikanthan P, Hevener AL, Karlamangla AS, 2010 Sarcopenia Exacerbates Obesity-Associated Insulin Resistance and Dysglycemia: Findings from the National Health and Nutrition Examination Survey III. PLoS ONE 5(5): e10805. doi:10.1371/journal.pone.0010805