Resveratrol may reduce Alzheimer’s biomarker, study suggests

A small study has found that resveratrol, a compound found in red grapes, red wine and dark chocolate, may help treat Alzheimer’s disease. Researchers at Georgetown University observed that it affects a biomarker for Alzheimer’s, but they cautioned that more studies are needed before resveratrol can be recommended for individuals with disease, which does not have a cure.

In their study, researchers reported that resveratrol helped stabilize amyloid-beta40 levels in the blood and cerebrospinal fluid of those who consumed the compound compared to the control group, which did not consume the compound and saw their amyloid-beta40 levels decrease.

In patients with Alzheimer’s, amyloid-beta levels decrease in the cerebrospinal fluid, while deposits of the substance increase in the brain, where it becomes insoluble. These insoluble plaques are a hallmark of the disease, which eventually leads to the death of nerve cells in the brain.

“Somehow, resveratrol is affecting cerebrospinal amyloid levels,” Dr. R. Scott Turner, director of the Memory Disorders Program at Georgetown University Medical Center, told “We don’t quite fully understand why or how, but [we] think it may be related to sirtuins.”

Sirtuins are proteins that are activated by caloric restriction. The biggest risk factor for developing Alzheimer’s is aging. Previous animal studies have found that long-term caloric restriction— eating two-thirds one’s normal caloric intake— prevents or delays most age-related diseases, including cancer, diabetes and heart disease.

The clinical trial, a phase II, placebo-controlled double-blind study, was published Friday in the journal Neurology.  The study was conducted with 119 participants, all with mild-to-moderate Alzheimer’s, ranging from age 50 to 90. The mean age for the resveratrol group was 70; the mean age for the placebo group was 73.

Researchers synthesized the resveratrol, creating a pure sample. Over the two-year study period, test group participants took two doses daily— equivalent to the amount found in about 1,000 bottles of red wine. The large dose was necessary because the compound rapidly metabolizes in the brain, but wouldn’t be ideal outside of a clinical setting, Turner noted.

“If we found more potent drugs that are maybe more bioavailable, maybe that would be a preferred strategy that could be pursued by drug companies,” he said.

In addition to the difference in amyloid-beta40 levels, researchers also observed that, compared to the placebo group, the resveratrol-treated group had fewer cancers and lost weight.

The resveratrol-treated group lost more brain volume than the placebo-treated group, which Turner said was unexpected but mirrors findings from other Alzheimer’s treatment studies.

“Is this good or bad? We don’t really fully know yet,” he said. “It doesn’t seem to be bad because patients aren’t worsening.”

Turner and his team are continuing to analyze the study data and hope to complete a phase III study to identify cognitive outcomes of the treatment.

For Turner, the results are less about resveratrol itself than a new method of treatment.

“We’re not recommending people take resveratrol,” he said. “I think we’re just cracking the door open to a new strategy that’s targeting aging mechanisms, as opposed to targeting amyloid directly.”