A new study published last week in the journal Neurology demonstrated that long-term, high-dose resveratrol stabilized amyloid-beta40 (Abeta40) in patients with mild to moderate Alzheimer's disease. This biomarker declines when the disease progresses.
Even though this is a single, small study, it is the largest and longest nationwide human clinical trial of high-dose resveratrol to date. The clinical trial was a randomized, phase II, placebo-controlled, double blind study in patients with mild to moderate dementia due to Alzheimer's disease. It had 119 participants taking 1 g of resveratrol orally two times per day. The patients who were treated with the resveratrol over 12 months showed little or no change in Abeta40 levels in blood and cerebrospinal fluid. On the other hand, those taking the placebo had a significant decrease in the levels of Abeta40 compared with their levels at the beginning of the study.
A decrease in Abeta40 is seen as dementia worsens and Alzheimer's progresses. Resveratrol was measured in both blood and cerebrospinal fluid; the study suggests that resveratrol is able to penetrate the blood brain barrier.
The researchers studied resveratrol because it activates sirtuins, which are the same proteins activated by caloric restriction. While the major risk factor for developing Alzheimer's is aging, previous studies have shown this disease can be prevented or delayed by long-term caloric restriction. In addition, the patients taking a resveratrol supplement experienced weight loss while those taking the placebo gained weight.
Furthermore, the research team obtained brain MRI scans on participants before and after the study and found that resveratrol-treated patients lost more brain volume than the placebo-treated group. This has also been seen with some anti-amyloid immunotherapy trials. The research team hypothesizes that the treatments may be reducing inflammation or brain swelling, which is seen with Alzheimer's disease.
Resveratrol and other similar compounds are being tested in many age-related disorders. A new animal study published earlier this year in Scientific Reports demonstrated that resveratrol prevented age-related memory decline. It reported that treatment with resveratrol had significant benefits in learning, memory and mood function in aged rats.
The results showed that neurogenesis doubled in the rats given resveratrol compared to the control rats. The resveratrol-treated rats also had significantly improved microvasculature, indicating improved blood flow, and had a lower level of chronic inflammation in the hippocampus.
By Michael Jurgelewicz, DC, DACBN, DCBCN
Source: R. S. Turner, R. G. Thomas, S. Craft, C. H. van Dyck, J. Mintzer, B. A. Reynolds, J. B. Brewer, R. A. Rissman, R. Raman, P. S. Aisen. A randomized, double-blind, placebo-controlled trial of resveratrol for Alzheimer disease. Neurology, 2015; DOI:10.1212/WNL.0000000000002035