Continued interest in a traditional herbal remedy
The benefit of ginkgo biloba, the maidenhair tree, has long been recognized by traditional Chinese medicine with respect to a number of health disorders. In the West, the main interest centers on the benefit of ginkgo biloba supplements in preventing dementia and cognitive loss and improving memory. The benefit of this herb in relieving claudication (leg pain due to blocked arteries) has been supported by scientific studies. Results of studies on other benefits are inconsistent, although there is much anecdotal evidence from users claiming to have experienced the benefit of ginkgo supplements in a variety of conditions and diseases.
According to an overview by the University of Maryland Medical Center, Ginkgo biloba extract has been shown to improve circulation and thus could have an effect in conditions caused by decreased blood flow to the brain or other organs.
In addition, the flavonoids and terpenoids contained in the plant are potent antioxidants. Antioxidants act against the damaging effects of free radicals found in the environment or generated in the body. Free radicals cause tissue damage and also have a role in the development of cancer. Flavonoids have a protective effect on the cardiovascular system, nerves, and retina. Terpenoids dilate blood vessels and reduce platelet “stickiness” thus improving blood circulation.
Relative benefits in various conditions
The MedlinePlus record for Ginkgo biloba lists the conditions in which supplements have been investigated in scientific studies and indicates the grade of scientific evidence for each use (classification runs from strongly positive (A), through good (B), unclear (C) to fairly negative (D)). The conditions include claudication (leg pain from blocked arteries, A), dementia (A), cerebral insufficiency (B), acute hemorrhoidal attacks (C), memory impairment (C), altitude sickness (C), asthma (C), cardiovascular disease (C), side effects of chemotherapy (C), chronic venous insufficiency (C), cocaine dependence (C), cochlear deafness (C), depression and seasonal affective disorder (SAD) (C), diabetic neuropathy (C), dyslexia (C), gastric cancer (C), glaucoma (C), Graves' disease (C), macular degeneration (C), memory enhancement (C),mood and cognition in post-menopausal women (C), multiple sclerosis (C), premenstrual syndrome (C), pulmonary interstitial fibrosis (C), quality of life (C), Raynaud's disease (C), diabetic retinopathy (C), tinnitus (C), schizophrenia (C), sexual dysfunction (C), stroke (C), vertigo (C), vitiligo (C), mental performance after eating (D). Side effects, safe dosage and potential interactions with other medications are also covered.
Cognitive benefit is a matter of controversy
Recent studies have raised some doubts about the benefit of Ginkgo supplements in the treatment of cognitive decline and dementia. These are summarized below as well as the limitations of the studies leading to such statements.
An updated Cochrane review, published in 2009, assessed the safety and benefit of Ginkgo biloba in the treatment of existing cognitive impairment and dementia. The review was based on an analysis of 36 randomized, double-blind, placebo-controlled studies identified from the medical literature and other sources.
It was found to be a safe treatment, with no differences in side effects noted between participants given supplements and subjects given placebo. The authors of the review criticised some of the earlier studies for having very small groups of subjects and for their unsatisfactory methodology. Results from more recent trials were inconsistent. Three out of the four most recent studies found no difference between Ginkgo and placebo, while one found very large differences in favor of the herb. The authors of the review concluded: “The evidence that Ginkgo biloba has predictable and clinically significant benefit for people with dementia or cognitive impairment is inconsistent and unreliable.”
Also in 2009, Snitz and colleagues reported further results from the Ginkgo Evaluation of Memory (GEM) study, the largest single clinical study so far conducted on the effects of this herbal remedy in preventing cognitive decline and dementia. The study included 3069 subjects aged 72-96 years and was conducted in 6 US academic medical centers between 2000 and 2008. Subjects were followed-up for a median period of 6.1 years. The subjects received 120 mg of Ginkgo biloba extract or placebo twice daily.
The study did not find any decrease in the incidence of dementia, due either to Alzheimer disease or to other causes, in subjects given supplements. Furthermore, no effects were observed on overall age-associated changes in cognition, nor on changes in memory, attention, language or other specific cognitive parameters.
The authors themselves admit that the study had certain limitations. The most important of these is that the results of three neuropsychological tests were better in the placebo group right at the very outset of the study. This potentially could have masked some subtle differences between the group given placebo and the group given supplements. However, the authors claim that the differences in test results were small and not clinically significant.
Herbal company defends cognitive benefits
The results from the GEM study have been hotly disputed in a statement released by Dr. Willmar Schwabe GmbH & Co. KG, a herbal medicines company based in Karlsruhe, Germany, which manufactures ginkgo biloba supplements. The company director, Professor Michael Habs stated: “The current paper, describing secondary analyses of data from a previously published study, is methodologically so weak that it is of limited relevance.” The main criticism concerns the fact that cognitive decline was very slight, even in the placebo group. Dr Guenter Meng, Head of R&D at Schwabe, considers that the study would need to have continued for another ten years at least to obtain a level of cognitive decline that would enable any conclusions to be made. Another criticism is that 40% of study participants had actually stopped taking the supplements or placebo by the time of the secondary analyses.
In addition, positive results reported from earlier studies cannot be disregarded. It is clear from the MedlinePlus information given above that more gingko biloba research is required before the benefit of supplements can be truly assessed,
Safety and side effects of gingko biloba
As of now, these supplements continue to be widely prescribed and herbal tea prepared from this plant is generally considered to be a safe remedy. The main concerns are that it may cause allergic reactions in individuals who are allergic to poison ivy. It also increases the risk of bleeding and therefore should be avoided by people with bleeding disorders or immediately before surgery.
Ginkgo biloba seeds are potentially deadly and should not be consumed under any circumstance.
Like other herbal remedies, gingko biloba can interact with medicines to cause potentially dangerous side effects.
Persons who do not have the risk factors listed above may safely take the supplements for the conditions listed under categories A to C in Medline Plus. Ginkgo biloba supplements are widely available at moderate prices, both online and locally.
- Ginkgo biloba overview, University of Maryland Medical Center
- MedlinePlus record for Ginkgo biloba
- Abstract of Cochrane Review on Ginkgo biloba
- Ginkgo Evaluation of Memory (GEM) Study
- Schwabe Statement on GEM Study
Texan on December 13, 2011:
I developed a vertigo/loss of balance and upon taking ginkgo biloba 3 times a day for about a week, my vertigo has improved significantly. It works!!!
Steve Andrews from Tenerife on August 18, 2011:
This is Bard of Ely from my other account and as you know I take it daily. If I don't I am liable to migraine.
Gypsy Willow from Lake Tahoe Nevada USA , Wales UK and Taupo New Zealand on February 21, 2010:
Great hub on a controversial substance. I did take it for awhile but I got headaches which I don't usually get. I haven't come across poison ivy so I don't know my reaction to that. The older I get the more I need a brain boost, maybe I'll give it another shot. Thanks for the information. Great hub.
Krys W (author) from Abertawe, Cymru on February 20, 2010:
Phew! I'm glad I included that information and that you read the hub, Sara
Sara Tonyn from Ohio, the Buckeye State on February 13, 2010:
I've always wanted to try ginkgo biloba but never got around to it. Now I'm glad I didn't.
"The main concerns are that ginkgo biloba may cause allergic reactions in individuals who are allergic to poison ivy."
I am sooooooo allergic to poison ivy! It would be my luck to get an allergic reaction to ginkgo biloba as well! Thanks for the hub! :)
Eileen Hughes from Northam Western Australia on February 06, 2010:
Interest information, there is so much for and against medicines and supplement for health these days it is hard to know which to take.
I think the only way is if it works for you then take it with caution. I may need a bucket full if it helps with the memory. Thanks for that.
Krys W (author) from Abertawe, Cymru on January 26, 2010:
That is really interesting to hear, Dolores. It goes to show that far more unbiased, scientific studies are needed to explore fully ginkgo's potential.
Dolores Monet from East Coast, United States on January 26, 2010:
WriteAngled - my daughter has Down syndrome. She is in her 30's and started taking ginko as a supplement. She's always had her ups and downs but when taking the ginko, she became the wit of the party. She was making clever observations and was on a total wave of brightness that seemed linked to the ginko. Maybe it was all in her head. (oh, haha)
Krys W (author) from Abertawe, Cymru on January 22, 2010:
I keep meaning to try ginkgo for my lousy memory, but then I always forget to buy it when I'm in town ;)
Money Glitch from Texas on January 22, 2010:
I started using Ginkgo biloba went I went back to grad school and I know for a fact it was this supplement that enabled me to get through some of the difficult subjects. :) Thanks for sharing!
Krys W (author) from Abertawe, Cymru on January 15, 2010:
Prynhawn da, Bard. Studies show that ginkgo dilates blood vessels. I believe some types of migraine are due to vessels in the brain becoming constricted, so your experience makes sense. It's not listed in the MedlinePlus categorised conditions, which implies no proper studies have yet been done on this particular use of ginkgo.
Steve Andrews from Lisbon, Portugal on January 15, 2010:
I have been using it for many years and can say it works for me. At times I have run out and not been taking it for a while are the only times I have had migraine attacks and I have found websites that say it is a remedy for this. My experience has shown that to be correct.
CMHypno from Other Side of the Sun on January 13, 2010:
Hi WriteAngled, great info on Ginkgo Biloba. Its a supplement that I have never taken personally, but I have some friends who swear by it. I think like all things, if you think that Ginkgo is going to be useful for you, try it and see. Not every supplement is right for everybody.
Krys W (author) from Abertawe, Cymru on January 12, 2010:
Hi apricotmousse, that statement has to appear on any product that has not been approved for medicinal use by the FDA. Products that are marketed as dietary supplements, cosmetics etc rather than as medicinal products by law must not carry any claims about therapeutic effects.
apricotmousse on January 07, 2010:
I took this supplement before but I stopped using it because as what is always written in the bottles, "No approved therapeutic claim." Thank you for sharing your article.
Krys W (author) from Abertawe, Cymru on January 05, 2010:
Thank you, Tina. There are so many different personal testimonials and anti-testimonials. That is why I kept to scientific studies and arguments. Although they have their own biases, at least the statements made derive from observations of various sized groups rather than just one individual.
TINA V on January 05, 2010:
I have a friend who tried using the Ginkgo Biloba plus (by Sundown) as a herbal supplement because it says that it helps maintain healthy circulation. But he stopped using it because he doesn't feel any changes. This hub is a good source of information about this medicine.
Happy New Year!