The Ginkgo biloba tree species has been around unchanged for about 150 million years. That’s a long time, and the fact that it has survived unchanged perhaps suggests that it has powerful internal survival mechanisms which have been perfected very early on despite changing environmental factors over this time. Specimens more than a thousand years old have been reported in China, Korea and Japan.
Ginkgo is a very popular herb. In fact I would guess that most health practitioners who read the literature and are over 50 years of age are probably taking this herb regularly because it has some wonderful anti-aging properties. Interestingly it does not have well-documented traditional uses in the West but is a much more recent ‘discovery’. German scientists investigating the effects on circulation of some unusual herbs found that Ginkgo in particular has very important effects on the vascular (blood vessel) system.
Chinese herbalists, on the other hand, have known about Ginkgo for hundreds of years.
Note: Most clinical trials have been conducted on standardised extract which concentrates the active ingredients. The extract contains a complex of at least 26 identified components which have been standardised to contain 24% flavonoid glycosides and 6% terpenoids. If the product has not been standardised then there is no way of knowing how much of the active ingredient is in the tablet or capsule.
Ginkgo is well known for its effects on the vascular system and there are many clinical studies confirming this usage.
Peripheral vascular disease
In this condition the blood supply to the lower limbs decreases and there is usually pain on walking, absence of pulses, coldness and discolouration of the feet. A meta-analysis of five placebo-controlled trials using standardised extract of Ginkgo showed a highly significant therapeutic benefit over placebo.1
Cerebrovascular and cerebral insufficiency
Elderly patients often suffer from insufficiency of blood flow to the brain, with or without brain cell degeneration. Symptoms may include tinnitus (noise in the ears), dizziness, headaches, anxiety, tiredness, mental deterioration (poor concentration, absentmindedness and confusion) and may include transient ischaemic attacks (mini strokes lasting minutes only).
A review of 40 clinical trials using Ginkgo for cerebral insufficiency (insufficient blood flow to the brain) conducted between 1975 and 1991 showed positive results for all except one. A direct comparison between Ginkgo and a medical drug (dihydroergotoxine) yielded similar scores. In many of the studies Ginkgo was found to be significantly better than placebo.2,3
Studies on people with age-related cognitive impairment, senile impairment of the Alzheimer’s type, have also shown good results using Ginkgo, namely significant improvement in short-term memory, attention and social skills.4, 5
Tinnitus and sudden hearing loss
Ginkgo has been used successfully to treat ringing in the ears which is exceedingly difficult to cure and can cause a great deal of annoyance. In one trial there was a statistical reduction in sound volume after 10 weeks. No change was noted in the placebo group.6
Patients with sudden hearing loss treated with Ginkgo or a vasodilator drug had a better outcome with Ginkgo and fewer side-effects.
Ginkgo extract has been shown to improve peak flow rates in asthmatic children and adults. Ginkgo has also been used to prevent acute mountain sickness at moderate altitudes and decreases vasomotor disorders of the extremities.
Trials have demonstrated improvement in microcirculation; one of them showed improvement in retinal circulation while the other showed improvements in blood flow in nail-fold capillaries.7
Improved blood flow suggests that caution should be exercised in conditions where bleeding may be a problem, such as surgery or even delivery. Nevertheless, even studies in which patients were taking Warfarin have not shown any changes in clotting time or altered bleeding time.
The main side-effects, which are quite rare, include nausea, headache, stomach complaints and allergic reactions. With improvement in blood flow one can nevertheless expect an increased incidence of spontaneous bleeding.
The majority of studies comparing Ginkgo with placebo or even drugs indicate that the herb improves circulation and therefore the nourishment to tissues supplied by the blood vessels. Thus it can be used for peripheral vascular disease, cerebral ischaemia and poor blood supply to the retina, among others. It should be used long term, with the dose recommended varying between 120 mg of standardised extract and up to 240 mg per day. Don’t forget to try it in cases of tinnitus – there are not too many other remedies known to help.
1. Blume J, et al. Placebo-controlled double blind study on the efficacy of Ginkgo biloba special extract EGb 761 in the maximum-level trained patients with intermittent claudication. Zeit-schrift fur Gefasskrankheiten/Journal for Vascular Diseases 1996; 25(3):265-274.
2. Kleijnen J, et al. Ginkgo biloba for cerebral insufficiency. Br J Clin Pharmacol 1992; 34: 352-358.
3. Hopfenmuller W. Nachweis der therapeutischen Wirksamkeit einer ginko biloba-spezialextraktes; met-analysis von 11 klinischen studien bei patienten mit hirnleistungsstorungen im alter. Arznemittel-Forschung/Drug Research 1994; 44: 1005-1013.
4. Hofferberth B, et al. The efficacy of EGb 761 in patients with senile dementia of the Alzheimer type, a double blind, placebo-controlled study on different levels of investigation. Human Psychopharmacology 1994; 9: 215-222.
5. Kanowski S, et al. Proof of the efficacy of Ginkgo biloba special extract EGb 761 in outpatients suffering from mild to moderate primary degenerative dementia of the Alzheimer type or multi-infarct dementia. Phytomedicine 1997; 4(1): 3-13.
6. Morgenstern C. Ginkgo biloba extract EGb 761 in the treatment of tinnitus aurium. Fortschritte der Medizin 1997; 115: 7-11.
7. Koza KD, et al. Retinal blood flow after Ginkgo biloba therapy in fundus hypertonicus. Munchener Medizinische Wochenschrift 1991; 133: suppl 1, S47-S50.