By Amy Brownlee
We, as consumers, are always trying to find new products to buy in which to improve ourselves. In modern-day American culture, improving oneself has become synonymous with feeling younger and healthier. Gingko biloba extract is one of the popular herbal supplements being marketed to mainstream consumers as a "smart" and "anti-aging" drug (http://www.stevemorow.com/food.htm) which will work to help to increase their overall brain functioning in the normal population, as well as, those who suffer from mental impairment due to aging. Gingko biloba extract has also been labeled an anti-aging drug due to its antioxidant properties, its supposed free radical scavenger properties, as well as its reported increases in peoples overall mental functioning. You see advertisements for it on television, as well as, the Internet making a large number of different kinds of claims of Gingko bilobas benefits. The claimed benefits range from increasing overall brain functioning in normal people to people with mental impairment, to being a mood enhancer (http://www.televar.com/alpha/biloba.html), to helping with such slight conditions as cough and asthma, to helping increase circulation in patients suffering from painful vascular diseases to actually having "slimming" applications (http://www.mmpinc.com/WHATS.HTM). If all these claims are true, then Gingko biloba extract sounds like a "mulit-cure"drug for the entire population. This paper will attempt to reduce the confusion associated with the large number of claimed benefits of taking Gingko biloba by explaining what the research literature has to back up these claims. I had a hard time myself keeping track of all the reported claims. At this time, Gingko biloba extract is being marketed towards the entire population claiming that it will improve everyones overall mental functioning. This paper will also attempt by analyzing the research data to figure out who actually benefits from this drug - the normal population or just people suffering from some condition.
What is Gingko biloba and where does it come from?
The Gingko is one of the oldest living tree species dating back more than 300 million years. Individual trees can live up to 1,000 years. The Chinese have been using Gingko as an herbal treatment for over 5,000 years. Extracts taken from the leaves of the Gingko tree are used to treat a range of symptoms. However, the main mechanism how the Gingko biloba extract works is that it promotes vasodilation increasing blood flow to the brain and the extremities.
http://www.televar.com/alpha/biloba.html. Furthermore, it appears to be composed of a number of useful components such as the antioxidants Vitamin C and carotenoids and free radical scavengers. While the "jury is still out" on what antioxidants are capable of. It is "thought" that antioxidants combat free radicals, assist in skin repair, and the strengthening of blood vessels which is why they are associated with anti-aging. The free-radical scavengers in Gingko biloba are supposed to be effective in treating Senile Macular Degeneration.
A list of all the claims of taking gingko biloba
For all the ailments that ginkgo biloba extract is supposed to cure, it should be called a wonder-drug. It is suggested that gingko biloba can be used to treat:
-those suffering from conditions related to poor circulation/ circulatory disorders
- vertigo, tinnitus, inner ear disturbances, headaches
-associated with cerebral impairment -memory loss/impairment, mental fatigue, dizziness, inability to concentrate and dementia associated with Alzheimers, Parkinsons
-help in reducing pain associated with the vascular diseases such as lymphedema, edema, and Raynaurds disease, arteriosclerositic plaque
-asthma, bronchitis, coughs
-Senile macular degeneration - thought to involve free radical damage
What taking gingko biloba does to the bodys functioning
1. Taking Gingko biloba extract promotes the elasticity and strength in the blood vessels and capillary walls which strengthens the cardiovascular system, reducing tendency for clots. The antioxidant component of gingko biloba extract inhibits platelet aggregation, thinning the blood inside arterial walls which helps the walls retain flexibility hindering the formation of arteriosclerositic plaque. One can see how Gingko biloba extract might be helpful in treating people with vascular diseases.
2. Taking Gingko biloba moves blood and oxygen to the brain to enhance memory and mental alertness. The flavonoid component of gingko is responsible for dilating the micro-capillaries (part of the circulatory system) which increases the blood circulation and oxygen levels in 1) the brain which enhances mental alertness and memory and 2) the extremities which improves circulation throughout the body. Gingko can increases the bodys production of the universal energy molecule adenosine triphosphate, commonly called ATP. Increased ATP levels boost the brains energy metabolism of glucose and increase electrical activity and mental alertness.
3. Scavenges free-radicals that can damage cells and accelerate aging
The flavonoids in gingko are effective free-radical scavengers. As a free-radical scavenger, gbe helps to attack free radical which themselves destroy particular cells. For example, visual cells are destroyed by free radicals in senile macular degeneration. So GBE helps prevent "aging" by destroying free radicals.
The use of Gingko biloba extract is more popular in Europe and Asia than the United States. In 1988, doctors in Germany (where it is sold as an over the counter drug) wrote more prescriptions for it than any other drug. (http://wellmedia.com/news/week16/gingko.html). However, the U.S. FDA has labeled Gingko biloba extract "probably safe". The U.S. FDA has a reputation for being conservative in their assessment of products so Gingko biloba is considered an herbal supplement which when taken in small doses is considered relatively safe and free of side effects.
( http://www.televar.om/alpha/biloba.html).However, large doses can cause restlessness, diarrhea, nausea, vomiting whch is why smaller dosages administered up to three times a day is recommended. (http://www.damicon.ti/sd/gingko-biloba.html , http://www.smartbasic.com/glos.herbs/ginko_biloba.html ).
Out of 9772 patients taking Gingko biloba extract ( 44 double-blind studies), the amount of side effects were minimal. Gastrointestinal discomfort occurred in 21 cases, headache in 7 cases, and dizziness in 6 cases.
However, one of the effects of Gingko biloba extract is that acts as an anticoagulant which reduces the ability of the blood to clot. People with clotting disorders or who take anticoagulant medicine (even such minor over the counter medications such as aspirin) should be cautious about taking Gingko.(http://www.damicon.ti/sd/sd-gingko.html) (http://www.phytotherapeutic.com/gingko.htm)
Most recommended dosages for gingko biloba extract are concentrations with 24% flavones and 6% terpene lactones. The usual dosage is 120-160 mg per day taken in three divided doses. (http://www.televar.com/alpha/biloba.html)
Daily dosages are important, and it is important to divide the doses that are taken at different times due to possible negative side effects such as restlessness, diarrhea, vomiting, and nausea that might occur if a large dose is taken. (http://www.damicon.ti/sd/sd-gingko.html)
Furthermore, while results have been shown to occur as early as two weeks, it is important to note that GBE can take up to 12 weeks for improvements to be seen. http://www.wellweb.com/ALTERN/herbs/gingko.htm
So now that we know what some of the problems that Gingko biloba extract is supposed to help treat, we can look at the research literature, and see what claims have been validated by the research.
GBE as a a drug that will improve overall mental functioning
It has been suggested that Gingko biloba is an effective treatment for improving overall mental functioning because it causes an increase in ATP levels which boost the brains energy metabolism of glucose and increase electrical activity and therefore mental alertness. Furthermore, GBE causes increased blood flow to brain which inhibits memory loss. GBE has been promoted towards normal, healthy population as well as to those who suffer from some type of mental impairment due to aging.
GBE as a drug that will improve overall mental functioning in people suffering from mental impairment due to aging.
First we will look at the research that involves subjects suffering from some type of mental impairment due to aging. Rai (1991) found that treating 31 elderly patients suffering from some measure of memory loss improved their cognitive functioning when treated with gingko biloba extract. 12 subjects were were randomly selected to take 40 mg of Gingko biloba extract (24% flavonoids and 6% terpenes), while 15 subjects received a placebo. Using a range of psychometric tests, subjects were assessed at the beginning of the experiment, and then at 12 weeks and 24 weeks. Subjects, who received the Gingko biloba extract, significantly improved their performance on the psychometric tests. LeBears (1997), studied the effects of giving GBE vs. placebo in a study that included 309 patients with mild to moderate cognitive impairment caused by multiple infarcts. Of the group given 120 mg of GBE daily, the GBE appeared to stabilize and improve memory and basic cognitive functioning. Based on the ADAS-COG scale, 27% of the group receiving GBE developed an improvement in concentration which is equal to a 6 month delay in disease progression. 14% of the placebo group improved memory and basic cognitive functioning as well. Based on GERRI scale, 37% patients receiving the GBE recovered daily living function based, while 23% of those receiving placebo improved daily living function.. While the results showed a difference that was significant between those receiving the GBE and those receiving the placebo, LeBears stated that the results of the research study were inconclusive due to the fact that significance was incredibly small. In looking at the percentages, the placebo group improved quite a lot in comparison to the group that received the GBE. So there was a great deal of improvement due to placebo. So some possible confounding variable such as an increase in attention given to those in the study could have caused the improvements in these subjects rather than just manipulation of the independent variable.
In a study of 72 patients suffering from cerebral insufficiency, Grassel found a statistically significant improvement in short-term memory at 6 weeks and at 24 weeks for patients given gingko biloba extract when compared to the control group given a placebo. The study concluded that ginkgo biloba extract improves mental/mnestic ability.
In a study of 25 patients with Parkinsons and Alzheimers disease, Fungheld (1989) found significant improvement in mental functioning when given a daily dose of gingko biloba extract for one full year. Standard test, clinical evaluations, and a computerized EEG were used to test these subjects.
Taillander (1986) evaluated the effectiveness of GBE treatment for elderly patients suffering from cerebral impairment due to aging. He evaluated 166 patients suffering from some type of cerebral disorder using a specially devised geriatric clinical evaluation scale, and found a significant difference between control and GBE treatment groups at 3 months which progressively increased as a function of time. He concluded that gingko biloba treatment is effective in the treatment of cerebral disorders related to aging.
For 60 subjects suffering from cerebral insufficiency, Eckmann (1990) found overall progressive improvements in mental functioning for subjects treated with a daily dose (160 mg) of gingko biloba extract over a time period of 6 weeks when compared to a subjects given a placebo. Furthermore, the improvements increased progressively as a function of time. However, the largest number of improvements were noted within the 2nd and 4th week of the gingko treatments. At this time, two-thirds of the patients taking the GBE showed improvements. It is important to note, however, that one-fifth of the patients taking the placebo also showed improvements between the 2nd and 4th weeks. This study shows that ginkgo biloba extract is an effective treatment in improving the mental functioning of the elderly afflicted with cerebral insufficiency yet it appears the GBE treatment takes a few weeks time to take effect, and then causes greater improvements as time progresses. Furthermore, daily doses are important.
GBE as a drug to improve overall mental functioning in normal subjects
Warots (1991) study researched the effect of administering an acute dose (600 mg) of gingko biloba extract on the psychomotor and mnesic performance of normal, healthy subjects. The 12 female subjects were tested using a range of psychometric test 1 hour before and 1 hour after dosing. The results found no significance between dose of gingko biloba extract and placebo.
Subhan (1984) conducted a study researching the effects of gingko biloba therapy on the overall mental functioning of normal, healthy subjects. Out of a total sample of 8 females, a subject received gingko biloba extract in doses of 120, 240, 600 mg, and placebo in a randomized, double-blind crossover design. An hour after dosage, the subjects completed a series of psychometric tests in order to assess mental functioning. No statistically significant changes were noted on the Critical Flicker Fusion test, choice reaction time, or subjective rating of drug effects between gingko or placebo. However, a significant difference was found for memory when using the Sternberg memory scanning test when the subjects were given the 600 mg of gingko biloba extract when compared to performance when given placebo. It appears that an acute dose of gingko biloba extract can help temporarily improve a normal, healthy persons short-term memory.
Hindmarch (1986) appears to have replicated Sudhans (1984) experiment and findings. Eight normal, healthy female subjects received GBE in doses of 120, 240, 600 mg, and placebo in a randomized double-blind crossover design. The same psychometric tests as in the previous study were used and no significant differences were found using Critical Flicker Fusion test, choice reaction time, or subjective reactions of drug effect between GBE and placebo. However, once again, short-term memory as assessed by the Sternberg memory scanning test showed a significant improvement when the dose was 600 mg of GBE.
So while the samples are small, it is safe to assume that acute doses of gingko biloba extract do not instantly improve overall mental functioning except in cases of short-term memory. This does bring up the question of whether gingko biloba extract improves the mental functioning of normal, healthy people. One would need to conduct a study for an extended period of time as most "experts" on the drug claim that it can take up to 12 weeks in order to notice differences in cognitive functioning. Yet it is interesting to wonder how gingko biloba effect normal people since it is currently being marketed towards a mainstream group of consumers with a claim that it will help one to think clearer, improve mental alertness, as well as increase memory.
For people with atherosclerotic peripheral vascular disease, walking is very painful due to a decreased blood flow to limbs caused by the hardening of the arteries. Studies suggest that treatment with gingko biloba extract helps improve circulation to the extremities making it possible for patients to walk further with less pain. Schneiders study (1992) found that patients with atherosclerotic peripheral vascular disease significantly improved their walking ability (which was the tool used to measure effect) when treated with gingko biloba.
Bauer (1986) studied the effects of treating 36 patients with arteritis with gingko biloba extract, and gave 35 patients a placebo for 65 weeks. A significant difference in measurement of decreased pain and greater walking distance was measured at 6 months with subjects treated with Gbe over those taking placebo. Improvements continued throughout the entirety of the study.
In a study on patients with vascular diseases, Koltringer (1989) found that gingko biloba extract created increased microcirulcation or increased blood flow in the brains of 15 patients suffering from arteriosclerotic vascular diseases, thereby justifying the use of gingko biloba extract as a treatment for vascular diseases.
Treatment of lymphedema
Vettorell,et al. (1996) studied the anticoagulant effect of gingko biloba on lymphedema. 76 patients suffering from lymphedema were given a daily dosage of Coumarin 60mg, Gingko biloba 40 mg, and Melilotus 40 mg for 6-8 months. The study found significant improvement in lymphedema both in functional symptoms (pain heaviness in affected limbs) and the physical signs (edema, episodes of infection).
Treatment of Senile Macular Degeneration
Senile Macular degeneration frequently causes blindness due to possible free radicals which break down cells contributing to vision. Because Gingko biloba is a free radical scavenger, it is thought that treatment with GBE can help decrease the intensity of this condition. Furthermore, the GBE is thought to help improve this condition by promoting microcirculation to the eyes (http://www.all-natural.com/top-ten.html). A study by Lebuisson (1986) shows significant improvement in long distance visual acuity after treatment of GBE. However, GBE did not appear to show improvements in subjects visual field.
Decrease intensity of tinnitus and vertigo
Cano Cuenca et. Al (1995) conducted a study on the effects of Gingko biloba extract on vertigo and tinnitus. 70 patients suffering from vertigo were given a Gingko biloba extract (4 ml/12h) for 6 months. The conclusion of the study showed that the Gingko biloba extract had caused decreases in the intensity of vertigo and tenets which were statistically significant. In a 13 month treatment program, 103 patients suffering from tenets were treated with GBE or a placebo using the double blind method. All the patients condition who were treated with the GBE improved.
Gingko biloba extract has been marketed to the population as a "smart" and "anit-aging" drug. The research evidence suggests that Gingko biloba can clearly help the aging population who suffer from problems associated with aging.
There is a large number of research studies which support the use of Gingko biloba extract as treatment for elderly people who suffer from problems associated with mental impairment such as memory/loss, mental fatigue, inability to concentrate, and dementia associated with Alzheimers disease and Parkinsons disease. While Gingko biloba extract cannot reverse the aging process, it does appear to help with symptoms of mental impairment. However, it is not absolutely clear if Gingko biloba extract is a "smart" drug which will effectively help the normal, healthy population achieve greater mental clarity, mental alertness, and memory. Of the three studies [Hindmarch, 1986; Sudhan, 1984; Warot, 1991] analyzed in this paper, all three had sample sizes of 12 or less, used female participants, and studied the effects of dosage within one hour after dosage. A range of psychometric tests were conducted, and in one study no effect was found while in two studies only short-term memory was found to be significantly effected by an acute (600 mg) dosage of Gingko biloba. It has already been advised that people should not take large dosages of Gingko biloba extract because it could cause negative side effects. So at this time, it remains inconclusive how effective it is for normal people to take Gingko biloba extract. More studies need to be conducted using the a large normal, healthy representative population who take a small dosage of Gingko biloba extract for a time period over 12 weeks in order to make an opinion on its usefulness for the general population.
As stated above, Gingko biloba extract appears to be an effective treatment for relieving the symptoms associated with disorders related to aging. A number of studies concluded that Gingko bioba treatment is effective at relieving some of the symptoms associated with painful vascular diseases. In particular, the three research studies analyzed in this paper all concluded that Gingko biloba extract is effective at decreasing the pain and helping to increase walking distance in atherosclerotic peripheral vascular disease because its antioxidant effect.
While, Gingko biloba appears to be an effective treatment for a number of problems associated with aging, there were a number of studies which I could only find one study for a specific problem. However the one study on Lymphedema, Senile Macular Degeneration, Tinnitus, and Vertigo all concluded that Gingko biloba treatment had effectively improved some symptoms related to the particular problem. Obviously more studies are needed to conclude that Gingko biloba extract is an effective treatment for those problems
I have read that Gingko biloba is one of the most researched herbs. It is impossible for me to state that any of the claims are false considering that I have not looked at all the research. So I find it impossible to say that Gingko biloba is not effective in relieving the symptoms of anxiety, depression, headaches, asthma, bronchitis, coughs, and slimming applications because I could not find any research studies on those topics. However, the Chinese began using Gingko biloba extract 5000 years ago to treat asthma, bronchitis, and coughs (http://www.3dom.com/wisdom.htm) so I assume that the research on those problems is out there. I do have to say I am a bit skeptical about the idea that Gingko biloba extract could be taken for its slimming applications (http://www.mmpinc.com/WHAT.HTM) due to the anti-oxidant and free-radical scavenger properties of Gingko biloba. However, I have not seen the research and cannot make a opinion.
Basically, the research on Gingko biloba extract appears to conclude that it is an effective treatment for elderly people who suffer from problems or diseases associated with aging such as mental impairment and vascular disorder. It is inconclusive whether the normal, healthy population will benefit from taking a Gingko biloba supplement such as those marketed on television and the Internet. More research needs to be done with the normal, healthy population as its sample.
Bauer, U. (1986). Gingko Biloba extract in the treatment of arteriopathy of the lower extremities. A 65-week trial. Presse Medicale, 15(31) Sep 25, 1546-9.
Cano Cuenca, B., Marco Algarra, J., Perez del Valle, B., Pelliccer Pascual, F.J. (1995). The effect of gingko biloba on cochleovestibulary pathology of vascular origin. Anales Otorrinolaringologicos Iberoamericanos, 22(6), 619-29.
Eckmann, F. (1990). Cerebral insufficiency -- treatment with Gingko biloba extract. Time of onset of effect in a double-blind study with 60 inpatients. Fortschritte Der Medizin, 108(29), 557-60.
Fungheld, E.W. (1989). A natural and broad spectrum nootropic substance treatment of SDAT - the gingko biloba extract. Progress in Clinical and Biological Research, 317, 1247- 1260.
Gessner, B., Voelp. A., Klasser, M. (1985). Study of the long-term action of a Gingko biloba extract on vigilance and mental performance as determined by means of quantitive pharmaco-EEG and psychometric measurements. Arzneimittelforschung, 35(9), 1459-65.
Hindmarch, I. (1986). Activity of Gingko biloba extract on short-term memory. Presse Medicale,15(31) Sep. 25, 1592-4.
Koltringer, P., Eber, O., Klima, G., Rothlauer, W., Wakonig, P., Langsteter, W., Lind, P. (1989). Microcirculation in parenteral Gingko biloba extract therapy. Wiener Klinische Wochenschrift,101(6) Mar 17, 198-200.
LeBears, P.L. (1997) A placebo-controlled, double-blind, randomized trial f an extract of Gingko biloba extract for dementia.. JAMA, 278(Oct 27), 1327-332.
Lebuisson, D.A., Leroy, L., Rigal, G. (1986). Treatment of senile macular degeneration with GBE. A preliminary double-blind drug vs. Placebo study. Presse-Medicale, 15(31) Sep 25, 1556-8.
Meyer, B. (1986). Multicenter reandomized double-blind drug vs. Placebo study of the treatment of tinnitus with gingko biloba extract. Presse Medicale, 15(31) Sep. 25, 1562-4.
Rai, G.S., Shovlin, C., Wesnes, K.A. (1991). A double-blind, placebo controlled study of Gingko biloba extract in elderly outpatients with mild to moderate memory impairment. Current Medical Research and Opinion, 12(6), 350-5.
Schneider, B. (1992). Gingko biloba extract in peripheral areterial diseases. Meta-Analyse of controlled clinical studies. Arzneimittelforschung, 42(4)Apr, 428-36.
Subhan, Z., Hindmarch, I. (1984). The psychopharmocological effects of Gingko biloba extract in normal healthy volunteers. International Journal of Clinical Pharmacology Research, 4(2), 89-93.
Taillandier, J., Ammar, A., Rabourdin, J.P., Ribeyre, J.P., Pichon, J., Niddam, S., Pierart, H. (1986). Treatment of cerebral aging disorders with Gingko biloba extract. A longitudinal multicenter double-blind drug vs. placebo study. Presse Medicale, 15(31) Sep. 25, 1583-7.
Vettorello, G., Cerreta, G., Derwish, A., Cataldi, A., Schettino, A., Occhionorelli, S., Donini, I. (1996). Contribution of a combination of aplha and beta benzopyrones, flavonoids, and natural terpenes in the treatment of lymphedema of the lower limbs at the 2nd stage of the surgical classification. Minerva Cardioangiologica, 44(9), 447-55.
Warot, D., Lacomblez, L., Danjou, P., Weiller, E., Payan, C., Puech, A.J. (1991). Comparative effects of gingko biloba extracts on psychomotor performances and memory in healthy subjects. Therapie, 46(1) Jan-Feb, 33-6.
Psychology DepartmentThe Health Psychology Home Page is produced and maintained by David Schlundt, PhD.
Vanderbilt Homepage | Introduction to Vanderbilt | Admissions | Colleges & Schools | Research Centers | News & Media Information | People at Vanderbilt | Libraries | Administrative Departments | Medical
|Return to the Health Psychology Home Page|
|Send E-mail comments or questions to Dr. Schlundt|