Ginkgo Biloba

Ginkgo Biloba Ginkgo has become one of the most popular herbs of the last 2 decades. It primarily strengthens blood vessels and improves circulation, particularly to the brain.

Name: Ginkgo biloba is more commonly known as Maidenhair tree. Often called the ‘living fossil’, it has been in existence since the Jurassic era and it has been revered by the Chinese for centuries.

Part used: Leaves.

Be aware that in Chinese medicine the seed is used but it has totally different uses to the leaf.

Active constituents: The main constituents are Flavone glycosides such as quercetin, proanthocyanidins (also found as the major anti-oxidant component of grape seed extract). Terpene lactones called ginkgolides and bilobalides. Most commercial Ginkgo extracts nowadays are standardised to contain 24% flavone glycosides and 6% bilobalides.

Absorption and distribution of Ginkgo: Ginkgo extracts are well absorbed. Up to 60% of the extract is absorbed, blood levels peaking after 1.5 hours. Flavonoids are particularly distributed to aorta, eyes, skin and lungs. Activity in heart tissue remains nearly twice as long as in the skeletal muscles. The adrenal glands seem to be a particular target in the endocrine system. At 72 hours after ingestion levels in areas of the brain are 5 times the blood concentration.

What does Ginkgo do?

There are over 300 scientific studies supporting the efficacy and safety of Ginko biloba extract.

Antioxidant effect

Ginkgo extracts have shown an ability to protect cell membranes from free radical damage. Using red blood cells as test cells Ginkgo extracts not only stabilised the cell membrane but also enhanced the effect of the sodium-potassium pump leading to better membrane polarisation. The sodium-potassium pump is vital to the transport of materials into and out of the cell and causes an electrical charge across the membrane. This charge is particularly important in cells of the nervous system. The anti-oxidant effect is particularly useful when there is cell damage or tissue injury as any toxins and free radicals released by the damage will be dealt with more effectively. To be absolutely specific, damage caused by infarction, haemorrhage or other circulatory problem will benefit particularly from the use of Ginkgo.

Ginko extract also improves the utilisation of oxygen and glucose by the cells.

Effect on blood vessels

The primary effect is on the inside lining of blood vessels. Ginko extracts stimulate release of endothelium derived relaxing factor and prostacyclin, 2 chemicals that cause the blood vessels to relax, open up and allow greater blood flow to an area. This effect is greater in the veins thus allowing efficient re-circulation of old, used blood.

These effects lead to its use in cerebro-vascular insufficiency in the elderly. Cerebro-vascular insufficiency means poor or obstructed blood flow to the head and brain such as occurs with hardening of the arteries. Ginkgo has been found to improve the symptoms of memory loss (compare with the effect on nervous tissue below), vertigo, headache, tinnutis, low attention span and depression. Studies have shown Ginkgo to be at least equal to Hydergine (an orthodox drug) in the treatment of Alzheimer’s disease. Ginkgo reduces blood clotting and that also offers protection from strokes.

The effect Ginkgo has on peripheral vascular insufficiency (poor circulation to the extremities) has been strictly and reliably evaluated. In cases of intermittent claudication (blocked arteries to the legs) Ginkgo has been shown to improve pain free walking distance, increase total walking distance, increase resting limb blood flow, increase peak limb blood flow and decrease lactic acid levels in the exercised limb. Ginkgo has also been measured against and found superior to pentoxyphylline (an orthodox drug that opens up the blood vessels).

Research has also shown Ginkgo to be just as effective in other peripheral vascular problems such as Raynaud’s disease.

Other blood vessel related complaints that have shown improvement on clinical evaluation include erectile dysfunction (impotence) in men, tinnutis, vertigo and cochlear deafness due to vertebro-basilar (this is an artery supplying the head) insufficiency, varicose veins and haemorrhoids.

Flavonoids strengthen blood vessels by encouraging the production of collagen, a vital part of the structure of blood vessel walls. This makes Ginkgo an excellent treatment for varicose veins.

Nerve cell effects

Stabilising the electric charge of nerve cells and the antioxidant effect combined with Ginkgo’s action on increasing oxygen and glucose utilisation together with improving blood flow make it perfect for reversing the damage to brain cells caused by haemorrhage and stroke.

Ginkgo also promotes an increased nerve transmission rate and increases the synthesis of neuro-transmitters. This effect combined with the circulatory activity make it the perfect drug for Alzheimer’s and senile dementia.

Interestingly, it is not only the aged who experience memory improvement taking Ginkgo, normal individuals in younger age groups have shown improved results on memory tests when taking Ginkgo.

Another clinical finding is that Ginkgo seems to display an anti-depressant effect. Double blind studies indicate that Ginkgo may well work well enough on its own or can be used in combination with anti-depressant drugs.

Tinnitus

Given that nerve damage and certain blood vessel disorders can lead to tinnitus (the perception of ringing, hissing, or other sound in the ears or head when no external sound is present), some researchers have investigated whether ginkgo relieves symptoms of this hearing disorder. Although the quality of most studies was poor, the reviewers concluded that ginkgo moderately relieves the loudness of the tinnitus sound. However, a well-designed study including 1,121 people with tinnitus found that ginkgo (given 3 times daily for 3 months) was no more effective than placebo in relieving symptoms of tinnitus. Given these conflicting findings, the therapeutic value of ginkgo for tinnitus remains uncertain. In general, tinnitus is a very difficult problem to treat.

Platelet effects

Platelets play a major part in clotting of the blood. Ginkgo extract stops platelets sticking together and stops them producing the chemicals that lead to blood clot formation and so help to keep the blood flowing smoothly.

Anti allergic properties

Double blind trials have shown that Ginkgo helps to block the ‘typical weal and flare’ reaction that occurs in allergy. This effect occurs because Ginkgo is able to block the chemicals released during the allergic reaction. These results hold out hope that Ginkgo may indeed be useful in the treatment of eczema, asthma and other hypersensitivity reactions.

Effect on the retina

In double blind studies Ginkgo has shown impressive protective effects on the retina against free radical damage. Long distance visual acuity and macular degeneration show remarkable improvements. Diabetic retinopathy also has been shown to improve with Ginkgo use.

To summarise

Ginkgo has a useful role to play in the treatment of Alzheimer’s disease, senile dementia, memory loss, dizziness, tinnutis, cochlear deafness, vertigo, stroke/CVA/infarction, intermittent claudication, Raynaud’s disease, macular degeneration, erectile dysfunction, diabetic circulatory disease, arteriosclerosis (hardening of the arteries), thrombosis, varicose veins, after heart attack, headaches, migraine, depression.

Available Forms

Standardized extracts containing 24 – 32% flavonoids (also known as flavone glycosides or heterosides) and 6 – 12% terpenoids (triterpene lactones)
Capsules
Tablets
Liquid extracts (tinctures, fluid extracts, glycerites)
Dried leaf for teas

How to Take It

Paediatric

Ginkgo is not routinely used in children by the medical community. Therefore, it is not currently recommended to use ginkgo in children under 12.

Adult

Initial results often take 4 – 6 weeks, but should continue to accumulate beyond that period.

Memory impairment and cardiovascular function

Generally, 120 mg daily in divided doses, standardized to contain 24 – 32% flavone glycosides (flavonoids or heterosides) and 6 – 12% triterpene lactones (terpenoids). If more serious dementia or Alzheimer’s disease is present, up to 240 mg daily, in 2 or 3 divided doses, may be necessary.

Precautions

The use of herbs is a time-honoured approach to strengthening the body and treating disease. Herbs, however, contain components that can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a health care provider qualified in the field of botanical medicine.

GBE is considered to be safe, and side effects are rare. In a few cases, gastrointestinal upset, headaches, skin reactions, and dizziness were reported.

Because gingko decreases platelet aggregation (stickiness), there is some concern that it may increase risk of intracranial (brain) hemorrhage. In fact, there have been several reports of bleeding complications associated with ginkgo use. However, it is not clear whether ginkgo or another factor (such as the combination of ginkgo and blood-thinning medications including aspirin and non-steroidal anti-inflammatory agents such as ibuprofen) caused the bleeding complications. One human study found that a ginkgo extract significantly prolonged bleeding time when given along with cilostazol (Pletal), a commonly used medication that inhibits platelet aggregation.

Pregnant and breastfeeding women should avoid using ginkgo preparations. In addition, ginkgo use should be discontinued at least 36 hours prior to surgery due to the risk of bleeding complications.

Do not ingest Ginkgo biloba fruit or seed.

Possible Interactions

Ginkgo may alter the metabolism and effectiveness of some prescription and non-prescription medications. If you are being treated with any of the following medications, you should not use ginkgo without first talking to your health care provider:

Anticonvulsant medications

High doses of ginkgo could decrease the effectiveness of anticonvulsant therapy, such as carbamazepine (Tegretol) or valproic acid (Depakote), in controlling seizures.

Antidepressant medications

Taking ginkgo along with selective serotonin reuptake inhibitor (SSRIs) antidepressants – including fluoxetin (Prozac), sertraline (Zoloft), paroxetine (Paxil), and escitalopram (Lexapro) – may cause serotonin syndrome. This condition is characterized by rigidity, tachycardia (fast heart rate), hyperthermia (low body temperature), restlessness, and diaphoresis (sweating). Ginkgo may enhance the effects (both good and bad) of antidepressant medications known as MAOIs, such as phenelzine (Nardil).

Antihypertensive medications

Ginkgo may decrease blood pressure, so use of ginkgo along with prescription antihypertensive medications should be monitored by a health care provider. There has been a report of an interaction between ginkgo and nifedipine (Procardia), a calcium channel blocking drug used for blood pressure and arrhythmias.

Blood-thinning medications

Ginkgo has blood-thinning properties and therefore should not be used if you are taking anticoagulant (blood-thinning) medications, such as aspirin, clopidogrel (Plavix), dipyridamole (Persantine), heparin, ticlopidine (Ticlid), or warfarin (Coumadin). There has been bleeding in the brain reported when using a ginkgo product and ibuprofen (Advil), a non-steroidal antiinflammatory drug (NSAID).

Blood sugar lowering medications

Ginkgo was reported to increase insulin levels in healthy subjects and to decrease insulin levels in diabetic patients. Use ginkgo supplements under the supervision of a health care provider if you are diabetic and taking insulin or oral blood sugar lowering drugs.

Cylosporine

Ginkgo biloba may help protect the cells of the body during treatment with the immunosuppressive (decreases immunity) drug cyclosporine.

Thiazide diuretics

Although there has been one literature report of increased blood pressure associated with the use of ginkgo during treatment with thiazide diuretics, this interaction has not been verified by clinical trials. Nevertheless, you should consult with your health care provider before using ginkgo if you are taking thiazide diuretics.

Trazodone

There has been a report of an adverse interaction between ginkgo and trazodone (Desyrel), an antidepressant medication that resulted in an elderly patient going into a coma.

Alternative Names

Fossil tree; Kew tree; Maiden hair tree.

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