Ginkgo and the brain
Boost your brain bower with ginkgo biloba!
We've heard about it from friends, read about it in herb books, and seen it on television commercials. And everything we've heard, read, and seen says much the same thing: ginkgo biloba improves our mental acuity, our ability to recall and concentrate.
Long known as a "memory herb" in folklore, science is now validating the ability of ginkgo biloba extract (GBE) to improve our "mental dexterity." Researchers note that GBE affects the brain in three ways:
Gingko biloba extract increases blood flow to the brain. GBE helps keep blood vessels and capillaries flexible, aiding in the circulation of blood. This enhanced circulation means that the brain gets a better supply of oxygen, glucose (blood sugar), and nutrients. All of these are necessary for proper brain function. Simply put, the better "brain circulation" we have, the better the brain is going to work.
Ginkgo biloba extract strengthens brain cells. GBE is a powerful antioxidant. Antioxidants protect our cells from damage. Protecting brain cells results in stronger and healthier brain cell membranes.
Ginkgo biloba extract increases neurotransmission. Neurotransmitters are chemicals that make it possible for the brain to communicate with itself. They ferry messages from one brain cell to the other. GBE can normalize or boost the levels of certain neurotransmitters. Many researchers believe that a deficiency of neurotransmitters may play a role in Alzheimer's disease, Parkinson's disease, and depression.
Researchers may believe that GBE affects the brain in these three ways, but what does this mean for mental acuity? There have been a number of clinical studies using GBE over the past decades. Here are some of the results from the 1990s:
A 1991 double-blind, placebo-controlled study looked at how GBE effects mild to moderate memory impairment in elderly outpatients (G.S. Rai, C. Shovlin, K.A. Wesnes. Curr Med Res Opin 12, no. 6 (1991): 350-5). In this six-month study, 31 patients over the age of 50 received 40 mg of GBE or a placebo three times a day. The abstract notes that statistical analysis of the data suggests that GBE had a beneficial effect on cognitive function.
Perhaps one of the first 1990s studies to gain widespread attention was that done on "ginkgo biloba for cerebral insufficiency," by Jos Kleijnen and Paul Knipschild, and published in the British Journal of Clinical Pharmacology (October 1992). This study was actually a critical review of previous studies whose intent was to establish whether there is evidence on GBE's usefulness in cerebral insufficiency.
Cerebral insufficiency is a general term for a collection of symptoms that include difficulties of concentration and memory, absent-mindedness, confusion, lack of energy, tiredness, depressive mood, anxiety, dizziness, tinnitus, and headache. These symptoms have been associated with impaired cerebral (brain) circulation and are sometimes thought to be early signs of dementia.
The authors determined that at that time there were eight well-performed trials out of a total of 40, and, in their abstract, state "Positive results have been reported for ginkgo biloba extracts in the treatment of cerebral insufficiency. The clinical evidence is similar to that of a registered product that is prescribed for the same indication. However, further studies should be conducted for a more detailed assessment of the efficacy."
A 1994 study (Phytomedicine 1, 9-16) shows that regular administration of GBE has a positive influence on subjects with cerebral insufficiency. The study focused on "long-term and short-term memory, concentration power, maximum stress, mental flexibility, family problems, and general satisfaction of the patient with his or her life." None of the 90 subjects exhibited any pseudodementias (defined as dementia symptoms due to depression), nor were they using any substances that affected blood vessels. Positive effects were noted after six weeks of use.
Another 1994 study (Human Psychopharmacology 9, 215-22) reports on the use of GBE for senile dementia of the Alzheimer s type. A review of this study in HerbalGram magazine (34, Summer 1995) says that GBE is "one of the clinician's most useful tools for slowing down cognitive decline in the elderly."
In a double-blind study on memory impairment in the elderly (Clin Ther 15, no. 3 (May-June 1993): 549-58), 18 men and women with a mean age of 69.3 received a placebo or 320 mg of GBE or 600 mg of GBE one hour before performing tests that measured the speed of information processing. After taking GBE, results indicated an improvement in the speed of information processing.
A 1995 report in the Psychopharmacol Bulletin (31, no. 1 (1995): 147-58) reports on using GBE in dementia. It notes that GBE is among the most popular over-the-counter medicines in Europe, that the European medical community has recognized it "as an effective compound in the treatment of cerebral insufficiency," and that it has earned the "approval of the German BGA (Bundesgesundheit Amt) for use in the treatment of dementia."
In October 1997 came the "groundbreaking" study on GBE'groundbreaking not because of new information, but because it was published in the prestigious and mainstream Journal of the American Medical Association (JAMA). JAMA reported that GBE may be beneficial in the treatment of Alzheimer's disease.
This was followed up by a 1998 meta-analysis (an analysis of all studies available on a subject) that attempted to identify all English and non-English-language research in which GBE was given to subjects with dementia or cognitive impairment. In the abstract to this study, the authors note that ". & there is a small but significant effect of three to six month treatment with 120 to 240 mg of G. biloba extract on objective measures of cognitive function in Alzheimer's disease." (Arch Neurol 55, no. 11 (November 1998 ): 1409-15.)
So, you've heard about ginkgo, read about it, and seen it on television. Maybe it's time you tried it!
Ginkgo: What to buy?
When considering a ginkgo biloba extract, make sure you use a product that meets the specifications of the GBE used in the many studies. This is a product standardized to 24 percent flavonoids (ginkgo extract flavoneglycosides) and 6 percent terpenoids. If your GBE does not meet these specifications, there is no guarantee that you will get desired benefits.
|Clinical study terms |
clinical study: one using human subjects