Ginkgo biloba is one of the most popular herbal medicines in the U.S. today. Ginkgo biloba, also known as ginkgo, fossil tree, or maidenhair tree, is indigenous to China, but the ginkgo trees are now grown commercially in South Carolina. The trees can live for hundreds of years and grow to about 120 feet in height. Since the trees are resistant to harmful insects and microorganisms, it is no surprise to hear about ginkgo trees that are more than 1,000 years old growing in China and Korea. The trees grow well on college campuses, in arboretums, as well as in large cities as ornamental trees.
The fleshy plumlike seeds of the ginkgo tree are light green or yellow in color and have a strong, unpleasant odor when ripe. The leaves have a pretty fan shape and turn a golden yellow in autumn. The tree has an unusual habit of losing the majority of its yellow leaves all on a single autumn day. The leaves of Ginkgo biloba have traditionally been used for the relief of cough and asthma symptoms and to help improve one’s memory.
Improved Blood Flow
The concentrated extract of dried or fresh leaves of the Ginkgo tree has recently become a very popular medicine for the treatment of cerebral insufficiency; that is, a diminished flow of blood to the brain. Ginkgo biloba extract (120 milligrams per day) appears to be effective, especially in geriatric patients, against ailments associated with a diminished blood flow in the brain because of peripheral arterial disease.
Depending upon the duration and severity of the arterial disease (narrowing of the blood vessels), an elderly person may experience dizziness, short-term memory loss, depression, vertigo, tinnitis, dementia, absentmindedness, anxiety, headache, confusion, mood disturbances, and other ailments. These conditions often partially respond to the vasodilation and improved blood flow that results from the use of ginkgo.
The active constituents in ginkgo are believed to be flavone glycosides, and a number of terpenoids, including the sesquiterpene bilobalide and the diterpenoid ginkgolides A, B, and C. The Ginkgo biloba on the market is typically standardized to 24 percent flavone glycosides and 6 percent ginkgolides. Bilobalide acts together with the ginkgolides to increase blood circulation. Ginkgo leaves also contain the health-promoting proanthocyanidins and phenolic acids such as vanillic acid. Many of these compounds provide strong antioxidant activity.
The ginkgolides are potent inhibitors of the platelet-activating factor that is involved in the development of inflammatory, cardiovascular, and respiratory disorders. Since the ginkgolides inhibit the hyper-responsiveness of the airway passages in asthmatic patients, Ginkgo biloba has been used for the treatment for bronchial asthma.
Furthermore, clinical studies show that Ginkgo biloba extract helps patients with poor circulation in the lower limbs caused by arterial blockage in the legs. This condition is characterized by a cramping pain in the calf muscles after only a short walk. Patients using Ginkgo biloba experienced significant improvement in the amount of walking they could accomplish without pain, and the maximum distance they could walk also increased.
Tinnitus, or ringing in the ears, is a common problem among the elderly. One possible cause of tinnitus is an insufficient blood supply to the inner ear. Ginkgo extract has been shown to be effective against tinnitus in only a few studies. A recent study of 80 patients, however, failed to establish the effectiveness of ginkgo in the treatment of tinnitus.
Any Help for Alzheimer’s?
Ginkgo biloba extracts have shown some promise as a therapeutic intervention for early-stage Alzheimer’s disease. The extracts have been reported to relieve difficulties with short-term memory, attention span, and depression in the early stages of Alzheimer’s disease. Treatment with ginkgo may slow the progression of the disease and improve the quality of life in Alzheimer’s patients.
When 40 patients with senile dementia of the Alzheimer’s type received 80 milligrams of Ginkgo biloba extract three times a day, their memory and attention span were observed to significantly improve after only one month. Improvements were also seen over a three-month period in general psychopathology, social behavior and personality, and psychomotor performance such as speech. Researchers studying the results with Alzheimer patients suggest that ginkgo may provide improvements equivalent to a six-month delay in the progression of Alzheimer’s disease.
Typically, most of the studies with ginkgo have been conducted in predementia and pre-Alzheimer patients. Reliable information regarding whether memory improvement occurs in normal subjects using Ginkgo biloba extracts is lacking.
The normal daily dose of ginkgo is 120 to 160 milligrams of dried-leaf extract divided into two to three oral doses. This is taken for up to two months. For an improved shelf life, ginkgo should be protected from light and moisture when stored.
Any Side Effects?
There does not appear to be any significant side effects from using Ginkgo biloba by itself or when taken along with medications. Typically, there are no adverse effects seen in persons consuming levels up to 600 milligrams per day. There are a few persons who are hypersensitive to Ginkgo biloba. The side effects include headache, nausea, and mild gastrointestinal complaints. Itching and other allergic skin reactions are rare, and normally result from contact or ingestion of the fruit pulp of ginkgo. Pregnant and lactating women should not use Ginkgo biloba until further tests have been conducted and it is declared safe for such women.
Over the past 30 years many aging persons have experienced some positive results with Ginkgo biloba therapy. Ginkgo extracts have produced improvements in impaired memory, dizziness, poor perception, anxiety, and mood swings.
Remember: Herbal products and dietary supplements can have pharmacological effects, may produce adverse reactions in some people, and could interact with over-the-counter and prescription medications you may take. Discuss with your physician your decision to use any herbal product. Anything mentioned in this article is not intended to diagnose, prescribe, or treat any ailment.
Winston J. Craig, Ph.D., R.D., is a professor of nutrition at Andrews University, Berrien Springs, Michigan.