Derek Burnett
Derek Burnett is a Contributing Writer at Bottom Line Personal, where he writes frequently on health and wellness. He is also a contributing editor with Reader’s Digest magazine.
You’ve probably seen advertising or heard word-of-mouth recommendations regarding ginkgo biloba as a brain-boosting dietary supplement. It’s certainly tempting to think that you can restore or maintain your powers of memory by consuming something natural and traditional rather than a concoction mixed up in a pharmaceutical laboratory. But does gingko really help memory? Unfortunately, the research to date is not encouraging.
In its ideal form, ginkgo (as it’s often called) is an ancient remedy derived from the leaves of the Chinese ginkgo tree. In traditional Chinese medicine, it’s been used for hundreds of years to treat everything from inner-ear disorders to sexual dysfunction and heart trouble. Adding to its mystique, the ginkgo tree narrowly survived extinction during the last ice age and is thought to be the oldest existing species of tree in the world. In the US, thanks mainly to marketing efforts, its reputation is most closely attached to brain health and memory.
Ginkgo leaf extract contains several phytochemicals that appear conducive to brain health, including flavonol, catechin, terpenes, and flavonoids. It is thought to protect brain cells from oxidative damage, improve blood flow, and possibly inhibit the activity of beta-amyloid, a brain substance closely associated with Alzheimer’s disease.
One of the problems with attempting to improve memory with ginkgo is that supplements in general have several drawbacks. First, not everything purporting to be a supplement truly is one in the technical sense. A supplement is meant to be a non-food substance that you take to ensure you get a dietary requirement you may not be getting enough of by eating. For example, you need vitamin C, but if you’re not getting enough of it in your diet, you can take a vitamin C tablet as a supplement. Many things sold as supplements are not replacing dietary requirements, and that includes gingko, yet they’re lumped together with true supplements under the federal regulatory framework.
Within that framework, the FDA does not require that supplement manufacturers prove the effectiveness of their products. This, of course, is a different model than that used in drug manufacturing, where stringent clinical trials must be performed to prove efficacy before a medication is approved for a particular medical purpose. With supplements such as ginkgo, the manufacturer is responsible for backing up its own claims of efficacy, so it puts disclaimers on its labels and words its claims very carefully with phrases such as “enhances mental sharpness” rather than, say, “prevents dementia.” Often, this results in misleading claims that encourage overly optimistic expectations.
And it’s not just efficacy that the current federal framework doesn’t adequately address, but also purity and quality. Some ginkgo pills have been found to contain no ginkgo at all, but rather, just ground wheat, radish, and other plants. Besides such sins of omission, there are often sins of inclusion, where harmful substances are found in supplements. A recent review by ConsumerLab found that 60% of the ginkgo products it sampled failed its quality tests. When you’re purchasing a supplement, it’s always important to select a brand that has been given a quality seal by an independent organization, such as “USP Verified.” Or check with an organization such as ConsumerLab or LabDoor.
So, will ginkgo biloba help with memory? The research is mixed, tending toward negative. While most supplements have just a handful of studies examining their efficacy, gingko is the most-studied so-called “brain supplement.” Yet for the most part, the studies fall short of proving that ginkgo can prevent, cure, or slow dementia.
In 2009, JAMA published the largest-ever study on whether ginkgo could prevent dementia. Called the Ginkgo Evaluation of Memory (GEM) study, it gave ginkgo supplements or placebo to more than 3,000 adults for an average of just over six years. The question, “Does ginkgo improve memory” got its most robust answer to date. The GEM trial concluded that ginkgo was not superior to placebo in terms of slowing cognitive decline, reducing dementia risk, or keeping mild cognitive impairment from progressing to dementia.
Some subsequent studies have shown a bit more promise. For example, scores on cognition tests did improve slightly for people with Alzheimer’s disease or mild cognitive impairment after 24 weeks of supplementation with ginkgo. And people living with Alzheimer’s did better with their activities of daily living when they used ginkgo supplementation. However, with regard to the body of studies from which these findings were drawn, researchers noted that the trials’ methodological quality was “moderate to poor” and that more research was warranted given the studies’ limited sample sizes and inconsistent findings.
Taken altogether, according to the National Center for Complementary and Integrative Health, “There’s no conclusive evidence that ginkgo biloba is helpful for any health condition… Ginkgo neither helps prevent dementia or cognitive decline or prevents Alzheimer’s-related dementia from getting worse.”
Despite the shakiness of any evidence for ginkgo’s effectiveness in improving memory, the many studies performed to date do agree that supplementation with ginkgo appears generally safe…with some caveats. First, most studies have been founded upon an assumption of a dosage, deemed moderate, of 120 milligrams (mg) to 240 mg daily. Consuming larger amounts of ginkgo leaf extract could increase the risk or severity of side effects.
Sometimes people taking ginkgo experience skin reactions, palpitations, dizziness, stomach upset, constipation, and headache. Don’t take ginkgo if you’re on a blood thinner, since the two could interact poorly. Women should not supplement with ginkgo during the late stages of pregnancy, since it could cause early labor or lead to bleeding problems during delivery.
And no one should consume raw or roasted ginkgo seeds, which are toxic, as are the tree’s unprocessed leaves.
