The recent reaction from the natural products industry regarding the study on the effects of Ginkgo Biloba on preventing dementia, which were published in the November 19, 2008 (Vol.300, no.19) issue of the Journal of the American Medical Association (JAMA), have raised some interesting points.
To very briefly summarize the JAMA study, it was designed to “determine effectiveness of G biloba vs placebo in reducing the incidence of all-cause dementia and Alzheimer disease (AD) in elderly individuals with normal cognition and those with mild cognitive impairment.”(1) 3,069 volunteers participated in the randomized, double-blind, placebo-controlled trial through five different academic medical centers in the United States. The overall conclusion of this study was that Ginkgo Biloba had no effect on the rate of progression to dementia of patients with mild cognitive impairment.
So does this mean that Ginkgo should be given up on and forgotten? Its history says otherwise.
Ginkgo has been used for medicinal purposes for thousands of years. To this day, it is amongst the topmost selling supplements in North America, according to the U.S. National Library of Medicine.(2) The Mayo Clinic describes Ginkgo as having “promising early evidence favoring the use of ginkgo for memory enhancement in healthy subjects, altitude (mountain) sickness, symptoms of premenstrual syndrome (PMS), and reduction of chemotherapy-induced end-organ vascular damage.”(3)
It is also important to keep in mind that there has yet to be a drug of any type designated for primary use against Alzheimer’s disease.
Michael McGuffin, President of the American Herbal Products Association (AHPA), spoke with NPIcenter and explained his view of the JAMA publication’s research. “[This study] was a novel concept, the researchers scratched their heads and said ‘I wonder if…’ and what they found is that in their study, the answer is no.”
McGuffin went on to explain that this study ignores previous research regarding the herb, explaining that the researchers of the JAMA study “didn’t re-evaluate any other studies, they didn’t re-evaluate the usefulness of Ginkgo as an anti-oxidant, and there is a large body of information that supports the use of Ginkgo as an anti-oxidant, which of course has all sorts of benefits.”
So does that mean that it’s possible Ginkgo could still have benefits regarding dementia?
Mark Blumenthal, Executive Director of the American Botanical Council (ABC), commented on the study, explaining that “even though this large scale, six-year, 3,000 person trial failed to show any evidence towards preventing the onset of the symptoms, the fact is that there’s still a considerable body of evidence supporting the treatment of Ginkgo for patients that are experiencing dementia and or early stage Alzheimer’s.”
“There are no conventional drugs, approved by the FDA at this time, for prevention of dementia or Alzheimer’s. There is no standard against which to compare Ginkgo because there has been nothing that has been shown to work.” Blumenthal added.
McGuffin shared a similar opinion on the use of Ginkgo.
“There is some research on the use of Ginkgo to provide symptomatic relief when you’re already in a state of mild to moderate to serious dementia. Now in the United States we can’t make those kinds of claims, those would be drug claims, but nonetheless the science still supports that there’s at least a strong suggestion of value for that purpose.” McGuffin said.
Ginkgo also has other benefits, aside from those that are related to cognitive function. Amongst them are; increased blood flow, increased metabolism efficiency, treatment of infertility and impotence in males and it can help some skin disorders such as psoriasis.
Ginkgo has had some side effects reported, such as gastrointestinal discomfort and headaches. People who are on anti-depressants are also not recommended to take Ginkgo, as it can result in a negative drug interaction. Ginkgo is also not recommended for pregnant women, and in some cases can cause vomiting, restlessness and nausea in those who take it.
The point of the issue to remember is this; JAMA’s published research on the effects of Ginkgo Biloba on eliminating dementia brings the point back to the role of supplements in day to day lives. Ginkgo was not expected to be a magic bullet to end dementia or Alzheimer’s disease outside of this trial. It continues to have benefits to those who take it, and one widely-criticized report should not be able to cause one to forget all the previous research that has shown its positive properties.
(1) The Journal of the American Medical Association “Ginkgo biloba for Prevention of Dementia” Vol. 300 No. 19, November 19, 2008
(2) Medline Plus Website, http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-ginkgo.html December 9, 2008.
(3) The Mayo Clinic Website, http://www.mayoclinic.com/health/ginkgo-biloba/NS_patient-ginkgo December 9, 2008.