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Further clinical evidence points to benefits of resveratrol (found in wine) in preventing Alzheimer's disease

old man drinking wine

There is always so much bad publicity and hype about the dangers of drinking alcohol (liver disease, premature death) that the benefits of moderate drinking (2-3 glasses of wine a day) on reducing your risk of death (mortality) is often forgotten by the media. Red wine from certain regions of the world, grapes with thick skins, appear to have clear health benefits despite what the press have to say.

So it was good to come across another positive study in relation to a chemical found in wine and its potential benefits in preventing dementia and Alzheimer's disease. Prescription wine, here we come!

The blog has written about the potential health benefits of resveratrol in wine and a new study published recently in Neurology gave further evidence of the potential effects of polyphenols in Alzheimer's disease. See earlier article here.

The accumulation of amyloid plaques in the brain is often used as a biomarker for Alzheimer’s disease. But there is still plenty of debate amongst Alzheimer's experts on the role of amyloid plaques and whether they cause the disease or are just a result of other more destructive mechanisms. However, for now amyloid levels in the brain are a good indicator for progression.

The latest Resveratrol and Alzheimer's disease study Georgetown University, Washington

Scientists at Georgetown University Medical Centre in Washington DC  gave 119 participants with mild to moderate symptoms of Alzheimer's either one gram of synthesised resveratrol twice a day in oral form for 12 months, or a placebo containing no active ingredient. Note that the resveratrol was synthesised since the dose was many magnitudes higher than that found in wine or foods.

The study published on September 11th in 119 participants concluded that it " provides Class II evidence that for patients with AD resveratrol is safe, well-tolerated, and alters some AD biomarker trajectories."  Over the 12 months of the study, those in the placebo group showed signs that their Alzheimer’s was progressing, including reductions in in the level of amyloid beta protein in their blood (where it probably accumulates in the brain causing the classic symptoms of dementia). Those taking resveratrol, showed little or no change in amyloid beta levels in their blood and by implication had less accumulation of amyloid in the brain tissues where it can cause damage.

What is resveratrol?

Resveratrol is found in the skin of red grapes as well as in dark chocolate and in certain fruits and vegetables such as raspberries. For example, the Malbec grape, used extensively in Argentina and the Tannat grape found in Uruguay, have thick skins and contains high levels of resveratrol. Vine grapes grown in cooler climates have higher resveratrol levels than those from warmer climates such as Australia.

What does this new study mean - can red wine really prevent you from getting Alzheimer’s disease?

The jury is still out but the evidence continues to mount that resveratrol appears to have a positive impact, without any major side effects even at the very high doses used in this latest study. Doses many times higher than found in wine or raspberries! The good news is that even at high doses, there does not seem to be any negative impact.

The question many scientists are asking themselves is what is the mechanism by which resveratrol might protect against dementia and Alzeheimer's.

 In laboratory experiments, extreme low calorie diets have reduced age-related diseases and it is has been postulated that this might occur because of the activation of enzymes called sirtuins, which may alter gene expression and protect against the effects of stress, including a poor diet.

Resveratrol may activate sirtuins just like these extreme low calorie diets but the evidence is not conclusive.

Summary of the implications

This latest study published this month on the potential effect of resveratrol adds fuel to the fire about the health benefits of chemicals like this found in fruit, wine and even dark chocolate at relatively low levels. Other small clinical studies have also demonstrated benefits of resveratol on human health measures and overall drinking wine has a definite benefit in reducing mortality compared with teetotalers (in  moderation). For many years, scientists have proposed that the very high life expectancy in certain parts of France despite high saturated fat diets, the so called French Paradox, is related to daily consumption of wine in the population. 

The Washington study adds yet more positive data to the debate about resveratrol and hopefully a large scale study will confirm these initial promising findings.

More details on the Washington clinical are below:

A randomized, double-blind, placebo-controlled trial of resveratrol for Alzheimer diseaseR. Scott Turner, MD, PhD,  Ronald G. Thomas, PhD, Suzanne Craft, PhD,  et al
September 11th 2015
For the Alzheimer's Disease Cooperative Study

ABSTRACT

Objective: A randomized, placebo-controlled, double-blind, multicenter 52-week phase 2 trial of resveratrol in individuals with mild to moderate Alzheimer disease (AD) examined its safety and tolerability and effects on biomarker (plasma Aβ40 and Aβ42, CSF Aβ40, Aβ42, tau, and phospho-tau 181) and volumetric MRI outcomes (primary outcomes) and clinical outcomes (secondary outcomes).

Methods: Participants (n = 119) were randomized to placebo or resveratrol 500 mg orally once daily (with dose escalation by 500-mg increments every 13 weeks, ending with 1,000 mg twice daily). Brain MRI and CSF collection were performed at baseline and after completion of treatment. Detailed pharmacokinetics were performed on a subset (n = 15) at baseline and weeks 13, 26, 39, and 52.

Results: Resveratrol and its major metabolites were measurable in plasma and CSF. The most common adverse events were nausea, diarrhea, and weight loss. CSF Aβ40 and plasma Aβ40 levels declined more in the placebo group than the resveratrol-treated group, resulting in a significant difference at week 52. Brain volume loss was increased by resveratrol treatment compared to placebo.

Conclusions: Resveratrol was safe and well-tolerated. Resveratrol and its major metabolites penetrated the blood–brain barrier to have CNS effects. Further studies are required to interpret the biomarker changes associated with resveratrol treatment.

Classification of evidence: This study provides Class II evidence that for patients with AD resveratrol is safe, well-tolerated, and alters some AD biomarker trajectories. The study is rated Class II because more than 2 primary outcomes were designated. © 2015 American Academy of Neurology