Recently the supplement Gingko Biloba has been in the news quite a bit. To get the facts straight on gingko and what it can do, the Wellness Advisor sat down with nutritional expert Dr. Steven Yannicelli.
Steven Yannicelli, PhD, RD is the Director of Continuing Education at Pharmavite. Dr. Yannicelli is well versed in the area of supplements with major interest on bone and joint health. Prior to joining Pharmavite, Dr. Yannicelli was a Research Scientist who worked in the area of metabolic defects. As part of this experience he incorporated diet regimens which included various vitamin and supplement therapies to help infants, children and adults with medical conditions.
Wellness Advisor: What is gingko?
Dr. Steven Yannicelli: Gingko is an herb which comes from leaves of the gingko tree whose Latin name is Gingko Biloba. Originally, gingko trees were found predominately in China and Japan but are now cultivated in the U.S. and other countries. The dried gingko leaves are processed to extract and standardize the biologically actives ingredients.
WA: How is gingko supposed to help people?
Dr. Yannicelli: According to the German Commission E, a regulatory agency that approves safety and efficacy of herbal medicines in Germany, gingko extract is safe and beneficial in treating persons with specific mental or cognitive impairment, peripheral circulatory disorders, vertigo and tinnitus. The most common use of gingko is in memory and cognitive improvement.
Gingko is one of the most clinically studied botanicals in the marketplace. Over 120 clinical studies have been completed; the majority of them reporting improvement in measures of memory and cognition in elderly persons with mild to modest mental impairment, including persons with Alzheimer’s disease. Similar results have also been reported in healthy elderly individuals given doses of 180 mg per day.
A recent Expert Panel organized by the Council for Responsible Nutrition and the American Botanical Council recently affirmed the benefits of gingko on memory and cognition in adults with early stage mental impairment and in specific circulatory disorders. The report by the Expert Panel will be published later in 2002.
WA: We’ve read quite a bit about gingko in the news lately. What are your thoughts on the recent study on gingko which challenges its claims on enhancing memory?
Dr. Yannicelli: A randomized clinical trial was conducted on 230 healthy elderly subjects given either gingko biloba or placebo for six weeks. The study, reported in the Journal of the American Medical Association, reported no differences in measures of attention, memory or cognition between those receiving gingko or those on placebo. However, caution must be made in the interpretation of this paper. As with all clinical studies there are some that show benefit while others do not. What is important is that in total there is compelling evidence that a benefit does exist. Reasons for different conclusions in studies of similar nature are numerous but include the dose given to subjects, length of time on the product or supplement and the number of subjects tested.
In the JAMA study ’healthy’ elderly subjects were tested. Measuring mental improvements in persons without mental impairment is very difficult to do and requires thousands of subjects, not just a couple of hundred as in the JAMA study. In the current study, subjects were tested for only 6 weeks which may not be a sufficient amount of time to see results. Other studies showing a positive effect of gingko and on memory and cognition were done with larger doses and over longer periods of time.
Of importance, but not mentioned in the JAMA study, is the time of day when the tests were performed and whether subjects were instructed not to consume caffeinated beverages prior to testing. Both of these issues can influence concentration, memory and other mental tests. Lastly, researchers in this study did not measure the level of active ingredients in the gingko supplement given to subjects, but use label claim only. It is widely known that quality of supplements and amount of active ingredients in herbal products can vary greatly. For this reason, we do not know if all the subjects given gingko were actually receiving the same amount of extract.
WA: So if gingko works for me I can continue to take it?
Dr. Yannicelli: Yes. The results from the JAMA study contribute to our knowledge of gingko, but are not the final or conclusive word on the subject. For this reason, if a person is currently taking gingko and finds benefit it is important not to stop supplementation but to first talk with his or her clinician.
