Ginkgo is the world’s oldest living tree. Darwin called it a “living fossil.” A form of Ginkgo first appeared around 300 million years ago and flourished throughout the time of the dinosaurs. It is a very hardy tree, resistant to pests and pollution, and can live as long as one thousand years. In the U.S., it is often planted as an ornamental tree along freeways because of its durability. In Japan and China, it is a familiar sight around temples.
It is the subject of intense worldwide research and over five million Ginkgo prescriptions a year are written in Europe alone with sales exceeding more than $500 million. In numerous clinical trials involving geriatric patients, remarkable success has been demonstrated using Ginkgo extract to treat cerebral insufficiency (insufficient blood flow to the brain).
The symptoms of cerebral insufficiency include short-term memory loss, dizziness, headache, ringing or buzzing in the ears, lack of alertness and depression. In several studies without a control group, the symptomatic improvement was found to be 60 to 78%. In double blind studies, results were equally impressive with an improvement rate which ranged between 44 and 92%. Participants who took placebos showed a 14 to 44% rate of improvement.
In long-term studies, Ginkgo produced no side effects and there was no decrease in its effect over time. Like nature, however, Ginkgo is slow in acting, taking four to eight weeks before benefits may be noticed. Improvements are gradual, but continue for up to a year or more.
The positive effect of Ginkgo biloba extract in geriatric patients has led many health practitioners to advocate its use in all people over 50. The benefits, however, are not limited to the geriatric group. In healthy young women, reaction time in performing a memory test was significantly improved after administration of Ginkgo extract (Int. J. Clin Pharmacol Res, 1984). Brain waves monitored on an EEG machine one hour after taking a high dose of Gingko biloba show stronger alpha and beta brain wave patterns.
Ginkgo’s ability to improve blood circulation to the brain and extremities makes it useful for many conditions. Hundreds of scientific studies performed over the past 50 years have demonstrated its effectiveness in treating hearing and vision problems, impotence, edema (water retention), varicose veins, leg ulcers, and circulatory diseases such as stroke and intermittent claudication (pain while walking). In animal studies, Ginkgo extract increased the ability of acetylcholine, a brain chemical, to bind to a receptor site. Reduced receptor binding of this neurotransmitter has been reported in Alzheimer’s disease.
Ginkgo biloba has certain active components to which its beneficial properties are attributed. A consistent pharmacological action can be expected when a 50:1 concentration made from the leaf is standardized to contain 24% ginkgo-flavone-glycosides and 6% terpene lactones. The terpene lactones are made up of ginkgolides and bilobalides.
Most research on Ginkgo has focused on the complex molecule Ginkgolide B, the terpine lactones believed to be responsible for many of the plant’s potent healing properties. The principle mechanism for the therapeutic action on Ginkgolide B appears to be its ability to inhibit PAF (platelet activating factor). PAF has been implicated in asthma and other allergic reactions.
Ginkgo extract can play an important role in improving circulation and mental acuity in people of all ages. For young people, this may translate to enhanced learning ability. In the elderly, it can mean a keener perception of life and improved mental functioning.
Other fascinating facts about Ginkgo biloba
In a double blind study, there was significant improvement in short-term memory following 600 mg. of Ginkgo biloba extract in comparison to a placebo. (Hindmarch, 1984)
Elderly patients had improved mental performance in a double blind study after taking Ginkgo biloba. (Gebner, Voelp, Klasser, 1985)
Reprinted with permission from Health Store News, 1992.