Can vinpocetine help with memory loss?
BACKGROUND:With the growing prevalence of Alzheimer's disease and other forms of dementia, coupled with the scarcity of effective treatments, natural remedies are being examined as sources of potential benefits. Vinpocetine is one such supplement that was popular in the 1980s and has been undergoing a revival in interest. The supplement is made by chemically modifying a compound extracted from the lesser periwinkle, Vinca minor. A related species (the Madagascar periwinkle) was the original source of a number of vinca alkaloids which remain important in treating cancer.
The lesser periwinkle was found to contain another vinca alkaloid, vincamine, which affected blood flow in the brain. Vincamine was then modified to give vinpocetine which had fewer side effects. The drug was developed in Hungary and soon had a reputation throughout eastern Europe for improving memory, slowing cognitive decline and improving brain function. It was also alleged to prevent clot formation and to be useful when given to people shortly after they had a stroke. Vinpocetine is also said to have antioxidant effects.
Although treated as a medicine in some countries, vinpocetine is regulated as a food supplement in the US. This has opened up new markets for the supplement, especially over the internet, and led to interest in its use as a cognitive enhancer and “natural” memory booster.
EVIDENCE FROM STUDIES:Numerous laboratory studies were conducted on vinpocetine in the 1970s and 1980s. These demonstrated a wide range of effects on biochemicals and cells found in the human brain. A few animal studies showed positive effects on memory. Several studies were performed on humans, but many of these had serious design problems. The results have been inconclusive, with some finding beneficial effects and others not. Although websites claim that hundreds of scientific studies support the use of vinpocetine to prevent age-related cognitive decline and boost brain power, two Cochrane Collaboration systematic reviews have reached much more sober conclusions.
The first of these examined vinpocetine for treating mild to moderate dementia. Only three studies were of sufficient quality to be included in the review, with the most recent one published in 1991. Although some beneficial
effects were found, the reviewers concluded that the overall results were inconclusive. In addition, few patients were treated for more than six months, which is a major limitation with a treatment intended for long-term use in conditions such as Alzheimer’s disease.
The second Cochrane review focused on vinpocetine as a treatment for strokes and was published in 2009 (as was an update of the other Cochrane review). Only two randomised controlled studies were found where vinpocetine was given to patients within 14 days of a stroke. In both studies, the vinpocetine was given intravenously. No significant differences were found in the number of patients who died or were dependent on others at one or three months after treatment with either vinpocetine or placebo.
PROBLEMATIC ASPECTS:Few adverse effects have been reported in clinical trials. Most of the problems were relatively mild gastrointestinal ones. However, dizziness, headache and sleep disturbances were also reported. A few people had short-term decreases in their blood pressure.
RECOMMENDATIONS:Given that some useful effects have been found in studies, vinpocetine continues to attract interest. Further research is being conducted, such as recent PET and CT studies which showed that vinpocetine does change blood flow within the brain. However, much further research is needed before results such as these can be used to recommend vinpocetine to patients. The use of vinpocetine to enhance memory in healthy patients is not supported by any recent evidence.
Dónal OMathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing, Dublin City University. He is author of Alternative Medicine: The Christian Handbook, Updated and Expanded Edition, Zondervan, 2007
