Supplements of a compound found in red wine appear to stabilize the blood levels of a protein associated with Alzheimer’s. Since this protein – amyloid beta 40 (Abeta40) – usually builds up in the brain as the disease develops, it's assumed that levels consequently drop in the blood. But those with mild to moderate Alzheimer’s who were given the compound did not experience an anticipated decline in blood levels of Abeta40, according to a new study published in Neurology.

The research does not conclude that the compound, called resveratrol, can be used to treat Alzheimer’s, as the study author Scott Turner says in a statement: “This is a single, small study with findings that call for further research to interpret properly.” It confirms the compound's safety at large doses when compared with a placebo, and allows the researchers to move on to a phase three trial with a much larger study group to confirm its effectiveness.

Resveratrol is a chemical known as a phenol and is produced naturally by plants in response to injury. Found in a range of products, from red wine to dark chocolate and raspberries, it has long been claimed to have various health benefits, though human studies have been few and inconclusive.

The reason this compound was chosen for the current study is because it activates proteins called sirtuins. Previous studies have shown that extreme calorie restriction reduces age-related disease in lab animals, and it’s suggested this happens due to the activation of sirtuins, which seem to affect gene expression and protect against stress. Although some studies appear to question this. One, for example, found that genetically modified nematode worms and fruit flies that produce more sirtuins were probably only longer-lived due to unrelated genetic factors.

To test the effect of resveratrol on Abeta40, the researchers conducted a randomized, placebo controlled double blind study over one year. This simply means that not only did the 119 patients involved in the trial have no idea if they were given the drug, neither did the researchers. Over the year, the patients were also given increasing doses of the drug, to test for any adverse side effects. The results suggest that resveratrol maintained the levels of Abeta40, a biomarker which has been associated with the progression of Alzheimer’s, in the blood.

“A decrease in Abeta40 is seen as dementia worsens and Alzheimer’s disease progresses; still, we can’t conclude from this study that the effects of resveratrol treatment are beneficial,” explained Turner, from Georgetown University Medical Center. “It does appear that resveratrol was able to penetrate the blood-brain barrier, which is an important observation.” This is obviously important if the compound is to help prevent the build-up of Abeta40 in the brain.         

An unexpected outcome of the trial was that those who were taking resveratrol lost more brain volume than those just on the placebo. “We’re not sure how to interpret this finding,” admits Turner. It could be that the compound reduces brain inflammation found with Alzheimer’s.

The results do not, however, mean we should all be drinking more wine or eating more chocolate – the doses of resveratrol involved equates to drinking around 1,000 bottles of red wine a day. Until more research is done, and the phase three trial completed, little more can be drawn from this study.