What Is It
The medicinal form of the herb is extracted from the fan-shaped leaves of the ancient ginkgo biloba tree, a species that has survived in China for more than 200 million years. (The leaves are double- or bi-lobed; hence the name "biloba")A concentrated form of the herb, ginkgo biloba extract (GBE), is used to make the supplement. Commonly called ginkgo, GBE is obtained by drying and milling the leaves and then extracting the active ingredients in a mixture of acetone and water.
What Does It Do
Ginkgo may have beneficial effects on both the circulatory and the central nervous systems. It increases blood flow to the brain and to the arms and legs by regulating the tone and elasticity of the blood vessels, from the largest arteries to the tiniest capillaries. It also acts like aspirin by helping to reduce the "stickiness" of the blood, thereby lowering the risk of blood clots. Ginkgo appears to have antioxidant properties as well, mopping up the damaging compounds known as free radicals and aiding in the maintenance of healthy blood cells. And some researchers report that it enhances the nervous system by promoting the delivery of additional oxygen and blood sugar (glucose) to nerve cells.
• Slows the progression of Alzheimer's symptoms; sharpens memory and concentration, particularly in older people.
• Lessens depression and anxiety in some older people.
• Alleviates coldness in the extremities (Raynaud's disease) and painful leg cramps (intermittent claudication).
• Helps headaches, ringing in the ears (tinnitus), and dizziness.
• May restore erections in men with impotence.
Interest now centers on ginkgo's possible role as a preventive for age-related memory loss. Unfortunately, there's little scientific evidence ginkgo will make most people better able to focus or remember. So far, it is those already suffering from diminished blood flow to the brain (not healthy volunteers) who have benefited most from taking the herb. Current research is trying to determine whether ginkgo's ability to help prevent blood clots may stave off heart attacks or strokes.
The fact that ginkgo aids blood flow to the brain thus increasing oxygen - is of particular relevance to older people, whose arteries may have narrowed with cholesterol buildup or other conditions. Diminished blood flow has been linked to Alzheimer's and memory loss, as well as to anxiety, headaches, depression, confusion, ringing in the ears, and dizziness. All may be helped by ginkgo.
Ginkgo also promotes blood flow to the arms and legs, making it useful for reducing the pain, cramping, and weakness caused by narrowed arteries in the leg, a disorder called intermittent claudication. There are indications that the herb may improve circulation to the extremities in those with Raynaud's disease, or help victims of scleroderma, an uncommon autoimmune disorder.
In addition, by increasing blood flow to the nerve-rich fibers of the eyes and ears, some studies suggest ginkgo may be of value in treating macular degeneration or diabetes-related eye disease (both leading causes of blindness), as well as some types of hearing loss. Ongoing studies are assessing the possible effectiveness of ginkgo in speeding up recovery from certain strokes and head injuries, as well as in treating other conditions that may be related to circulatory or nervous system impairment, including impotence, multiple sclerosis, and nerve damage tied to diabetes. Traditional Chinese healers have long used ginkgo for asthma, because the herb appears to alleviate wheezing and other respiratory complaints.
How To Take It
Dosage: Use supplements that contain ginkgo biloba extract, or GBE, the concentrated form of the herb. As a general memory booster and for poor circulation: Take 120 mg of GBE daily, divided into two or three doses. For Alzheimer's disease, depression, ringing in the ears, dizziness, impotence, or other conditions caused by insufficient blood flow to the brain: Take up to 240 mg a day.
Guidelines For Use: It commonly takes four to six weeks, and in some cases up to 12 weeks, to notice the herb's effects. Generally, it is considered safe for long-term use in recommended dosages. You can take ginkgo with or without food. No adverse effects have been reported in pregnant or lactating women who take the herb.
Possible Side Effects
In rare cases, ginkgo may cause irritability, restlessness, diarrhea, nausea, or vomiting, though these effects are usually mild and transient. People starting the herb may also notice a headache during and first day or two of use. If side effects are bothersome, discontinue it or reduce the dosage.
A yearlong study, published in the Journal of the American Medical Association, evaluated 202 patients with dementia, most of whom also had Alzheimer's disease. Patients who took 120 mg of ginkgo biloba extract a day were more likely to stabilize or improve their mental and social functions, compared with those given a placebo. The effects were modest and of limited duration.
• A yearlong study, published in the Journal of the American Medical Association, evaluated 202 patients with dementia, most of whom also had Alzheimer's disease. Patients who took 120 mg of ginkgo biloba extract a day were more likely to stabilize or improve their mental and social functions, compared with those given a placebo. The effects were modest and of limited duration.
• Ginkgo is expensive - anywhere from $10 to $30 for a month's supply. Residents of countries where ginkgo is an official medication for "circulatory disorders" are often reimbursed by government health insurance.