Ginkgo Biloba – A Boost for Aging Brains
It’s the most promising well-tested nonprescription antiaging “smart drug” or “cognitive enhancer,” say many researchers. It’s ginkgo biloba, approved in Germany for a decade to revive failing memory. The scientific buzz on ginkgo is so good that countless prestigious American scientists and doctors, many in middle age, are now taking it, hoping to stave off memory loss as they get older. Dr. Jerry Cott, age fifty-two, chief of research on pharmacological treatment at the National Institute of Mental Health, takes 240 milligrams of ginkgo daily as “insurance” against declining memory. He thinks it’s a reasonable and inexpensive precaution, based on current evidence. He also believes ginkgo has improved the mental functioning and well-being of his elderly mother who has Alzheimer’s disease.
Dr. Norman Rosenthal, a research psychiatrist at NIMH, in his late forties, takes 120 milligrams of ginkgo every day. Dr. Lester Packer, age seventy, professor of cellular biology and chemistry at the University of California at Berkeley, takes 30 milligrams of ginkgo daily, as a brain-protecting antioxidant. Dr. Turin Itil, world-renowned neuropsychiatrist and author of pioneering studies on ginkgo and Alzheimer’s disease, has been taking 120 milligrams of ginkgo daily for four years. In his seventies, he says it has made a remarkable difference, especially in recalling numbers.
“Before I took ginkgo, I could never remember phone numbers. Now my secretary is amazed at how I can recall them. Practically all my friends and family over age sixty-five are taking ginkgo, at my suggestion,” he adds. Dr. Itil is a clinical professor of psychiatry at New York University Medical Center and chairman of the World Health Organization’s International Advisory Committee on the Diagnosis, Prevention, and Treatment of Alzheimer’s Disease.
What do these prominent researchers know that you need to know? Why are they and thousands of other leading brain researchers and doctors throughout the world taking ginkgo biloba?
Compelling evidence is found in the pages of many medical journals worldwide. About 250 studies of ginkgo pharmacology and efficacy have been published in the last fifteen years. More than fifty controlled clinical trials, most done in Europe, proclaim ginkgo biloba a successful treatment for diminished age-related memory and concentration, increased absentmindness, confusion, dizziness, tinnitus (ringing in the ears), and Alzheimer’s disease. Ginkgo is specifically approved by the German government for such conditions.
POWERFUL, DIVERSE PROTECTION
Ginkgo biloba, an extract from leaves of the ginkgo tree, promises so many brain-protecting properties it’s impossible to know which are most important. Dr. Packer praises ginkgo’s strong antioxidant activity. He has shown that ginkgo zaps two of the most virulent free radicals—superoxide and the hydroxyl radical—that readily savage brain cells. Dr. Packer also notes that ginkgo neutralizes the free radical nitric oxide that fosters blood vessel and brain cell damage, notably by triggering inflammation. Thus, ginkgo is an anti-inflammatory—a big plus for the brain.
Ginkgo increases circulation of blood and oxygen to the capillaries of the brain, studies show, probably by reducing blood viscosity. Many experts think this alone makes ginkgo a formidable brain-booster. Dr. Itil also notes that ginkgo increases glucose (sugar) metabolism in the brain which is another possible way ginkgo works to maintain or rejuvenate memory. French researchers found that ginkgo directly boosted neurotransmitter activity, possibly by restoring or preserving the integrity of nerve cell membranes.
Electroencephalograms (EEGs) show that ginkgo produces striking pharmacological activity in the brain. Dr. Itil found that in both young men, average age thirty-two, and elderly people with impaired memory, a standardized brand of ginkgo (Ginkgold) acted as a “cognitive activator,” increasing alpha brain wave activity in all areas of the brain. The increased brain wave activity was evident within an hour to three hours after taking ginkgo. Gingko also may reverse brain aging by stimulating the regrowth of nerve cell receptors that have been lost to aging, and combating the process called “excitotoxicity” that disables and destroys brain cells.
GINKGO HELD OFF ALZHEIMER’S
Gingko’s big moment came in 1997, in a double-blind study published in the Journal of the American Medical Association. Dr. Itil and colleagues, including Dr. Pierre Le Bars, tested ginkgo (known as Schwabe EGb76 I or Ginkgold) in a daily dose of 120 milligrams on 137 patients with dementia caused either by strokes or Alzheimer’s. After a year, fully 30 percent of those with dementia performed better on tests of memory and reasoning and were judged better in social behavior and mood by caregivers than those on placebo. Bottom line: Those on ginkgo did not show signs of worsening mental deterioration, as did those on the dummy pill, and even improved slightly in social functioning. Researchers speculated that a higher dose-240 milligrams daily—might be more effective when the brain deterioration is so advanced.
Many researchers start taking ginkgo soon after hitting middle age. Their rationale: If ginkgo retarded such a frightening disease as Alzheimer’s, it makes sense that it can intervene earlier to prevent the symptoms of Alzheimer’s in the first place. After all, as experts say, Alzheimer’s does not come on overnight, but is a climactic event after years of gradual decline in brain functioning. Mild cognitive impairment (MCI), early signs of memory problems, is now thought to be a precursor of Alzheimer’s disease. Thus, if you delay or prevent such early detrimental brain changes, you may never progress to dementia-type brain damage.
GINGKO GOES ON TRIAL
The National Institutes of Health is so convinced of the brain-saving potenial of ginkgo that it has initiated a first of its kind $15 million trial to see if the herb can halt memory deterioration and onset of dementia, including Alzheimers, in vulnerable individuals. “It’s very exciting” says Dr. Cott. The double-blind study, conducted under the auspices of the National Center for Complementary and Alternative Medicine and the National Institute of Aging will give a daily dose of 240 milligrams of ginkgo or a placebo to 2,000 elderly men and women for six years. The subjects will also undergo tests of memory and general mental functioning. If those taking ginkgo are less apt to develop dementia or cognitive decline, researchers will have new proof of ginkgo’s ability to deter or delay brain deterioration.
THE “PERFECT” PILL FOR NORMAL AGING
But far more important to most people is the ordinary erosion in mental function and memory that comes with age‑primarily a reduction in the speed of processing information and short-term memory needed to recall telephone numbers, names and faces, for example. Ginkgo seems ideally suited to deal with such age-related memory decline. As Dr. Pierre Le Bars, leading ginkgo researcher and assistant clinical professor at New York University, points out, “The evidence does not really show ginkgo to be an overall booster of memory as—for example, in expanding long-term storage and retrieval of information.” Studies, he says, find that ginkgo primarily speeds up reaction times and accuracy involved in short-term and so-called “working memory” notably in people with some age-related decline.
In studies of sixty to sixty-five-year-olds with mild cognitive problems, ginkgo has improved short-term memory and working memory. Subjects were better able to focus on, store, and more rapidly retrieve recently learned information—such as a list of words—after taking ginkgo. That’s why some say ginkgo fills the precise gap of mild memory deficits suffered during normal aging.
At what age does memory generally start to decline? In some people memory may grow worse at age thirty, but in others not until forty, fifty, sixty, or even later, says Dr. Itil. And for some, memory loss never progresses; in others, it declines rapidly. Dr. Itil warns that it’s best to intervene immediately when you notice the first signs of memory impairment rather than waiting for it to worsen, possibly eventually progressing to dementia or Alzheimer’s. The fact that so much brain cell damage in advanced years is now thought to stem from free-radical damage and low antioxidant defenses also makes antioxidant ginkgo look better than ever as a brain saver.
GINKGO VS. STROKES
Fascinating research at the National Institute on Aging suggests that taking ginkgo may cut the severity of brain damage after a stroke. In experiments, scientists gave gerbils ginkgo and then cut off blood flow to the brain, inducing a stroke. In such situations, the brain is hit with high concentrations of the toxic arachidonic acid that can cause extensive damage many ways, notably by releasing free radicals and producing inflammation. The longer the arachidonic acid stays around, the more brain cells it can damage. Thus, the brain tries to recycle it as quickly as possible. What gingko did in the gerbil brains is hasten the uptake or removal of arachidonic acid. In a similar gerbil study, ginkgo also blocked cell death in the hippocampus.
Extrapolated to humans, it suggests that providing brain cells with ginkgo ahead of time might save them from death and damage in case of stroke.
Most early studies in Europe used a standard dose of 120 milligrams of ginkgo daily. Some researchers now advocate higher doses-240 milligrams daily. Even doses as high as 600 milligrams have been used experimentally. Still, the lower dose of 120 milligrams may, in fact, be best for most older people with the beginnings of memory problems. An interesting 1998 Danish study showed that 120 milligrams of ginkgo significantly improved intellectual function in men and women, average age seventy-four, with mild to moderate cognitive impairment. But a double daily dose of 240 milligrams, surprisingly, did not!
Those on the lower 120 milligram ginkgo dose scored higher on tests of attention, concentration, and short-term verbal memory after three months. Their diastolic blood pressure also went down. But those taking the higher 240 milligram dose did not improve test scores. Moreover, those on the high dose reported side effects, including sleep disturbances, dizziness, and dyspepsia.
It’s possible that ginkgo may have an “optimal” dose range for some people, beyond which too little or too much is not beneficial. Dr. Le Bars suggests first trying 120 milligrams and raising it after three to six months if you sense no improvement. Research shows you should notice improvement, he says, after a month or so. If you “don’t feel better” after four to six weeks of taking 120 milligrams, you can bump it up to 240 milligrams, but if that brings no signs of improvement in a few months, “forget it,” advises Dr. Le Bars. “You, along with half of the population, are not a ginkgo responder.”
Dr. Le Bars notes that not everyone can expect to get an intellectual boost from ginkgo. Only 50 percent at most of those who take ginkgo see improvement, research shows. Among those with severe memory loss or Alzheimer’s the figure is lower-30 to 40 percent. Any ginkgo benefit stops with 50 percent of the population, for unknown reasons, even at the higher dose of 240 milligrams daily, concludes Dr. Le Bars. He also feels that ginkgo is more apt to forestall early memory decline than to slow down or reverse advanced dysfunction, as in Alzheimer’s.
Ginkgo has been heralded as very safe, inducing only minor and reversible side effects, such as nausea. Recently, a couple of cases of excessive bleeding have been reported after taking ginkgo. Whether ginkgo was a contributing cause is unknown. However, some experts now advise anyone with a known bleeding problem, a history of hemorrhagic stroke, or who is regularly taking anticoagulants such as Coumadin or aspirin for heart disease, to consult a doctor before taking ginkgo. “It’s possible ginkgo might contribute to a bleeding problem,” says Dr. Le Bars, “although the chances are very remote.” Still, such a hazard can be avoided by having your doctor check the coagulation factors of your blood. If you are not on regular blood thinners, including aspirin, there should be no danger, says Dr. Le Bars.
What type? Not all ginkgo on the market is equal. Tests have found that even reputably “standardized” brands do not have equal benefits on the brain. In a test of three such commercial ginkgo products by Dr. Itil, only one EGb 761 (sold as Ginkgold) performed as a “cognitive enhancer.”
A WORD ABOUT PYCNOGENOLTM
Although ginkgo has been more widely tested as a brain-booster, some experts say another natural extract made from pine bark has extraordinary potential in protecting the brain from age-related deterioration and mental decline. It is PycnogenolTM, a strong antioxidant supplement produced in France and distributed by the Henkel Company in the United States.
New evidence from the Berkeley laboratory of Dr. Lester Packer shows that Pycnogenol possesses strong powers against certain free radicals, including nitric oxide that can be toxic to brain cells, especially in brains vulnerable to Alzheimer’s, Parkinson’s and other neurodegenerative diseases. Dr. Packer predicts that as new research reveals the brain-protective powers of Pycnogenol, it, like ginkgo, will become widely popular as a brain-boosting supplement.
BOTTOM LINE: Taking ginkgo may slow down brain damage such as Alzheimer’s that causes intellectual decay, and may help correct some memory lapses and cognitive impairment due to normal aging. There’s no evidence ginkgo is a “smart drug” in the sense of sharpening memory or boosting mental powers beyond normal functioning. It is not a pill young people could count on to boost scores on a test, for example. Indeed, gingko’s essence seems to be in slowing the gradual decline in mental faculties, notably in aging brains, because of its diverse pharmacological activity, including its strong antioxidant properties.