Companies selling the herbal supplement gingko biloba say it can enhance your memory.

But as this ScienCentral News video reports, scientific evidence on whether gingko works has been controversial at best.

Natural Memory Boost?

Improve your memory by taking something found in nature! And you don’t need a prescription! Is it too good to be true?

Gingko biloba, extracted from the leaves of the gingko tree and available in health food stores, supermarkets and countless internet sitesis one of the most widely used herbal treatments for improving memory, and people in the U.S. spend millions of dollars on it every year. The scientific community has taken note; the National Institute on Aging is currently supporting a clinical trial to evaluate the efficacy of gingko in treating the symptoms of Alzheimer’s disease.

“Gingko has become a very popular [supplement], partly because there is a sort of pent-up demand for something that will enhance memory and cognitive function,” says Steven Ferris of the Institute for Aging & Dementia at NYU Medical School. Sometimes the supplement is even marketed as a kind of “Brain Viagra,” with claims that it increases circulation in the brain and protects it from tissue-damaging substances. The American Herbal Products Association (AHPA) cites a review article in a British Journal that found “promising evidence of improvement in cognition with gingko.”

But not all scientists are convinced. An article in the April 2003 issue of Scientific American reviewed more than forty studies on gingko, and came to the conclusion that, “in general, the reported effects are rather small.” Paul Gold, a psychology professor at the University of Illinois at Urbana-Champaign and one of the authors of the article, says, “The information available is so uninformed that it’s difficult to imagine that a consumer would have a good reason to use gingko.”

“There’s been a fair number of studies testing gingko in various populations of patients and ordinary people to see if it improves cognition,” explains Ferris. “The main problem is that almost all of those studies were very poorly designed and really don’t properly address the questions of whether it really works or not in a scientifically valid way.”

For example, gingko researchers typically test their subjects with learning and memory tests after they have used the supplement for several months, making it hard to identify which brain functions have been affected. In order to get more specific data on gingko’s effects, researchers would have to test their subjects both before and after they take the supplement.

Also, for drugs manufactured by pharmaceutical companies, researchers typically conduct studies with lab animals before they test on humans. But the Food and Drug Administration doesn’t consider gingko a drug, so it is only regulated as a dietary supplement (a special category of food). The Scientific American article says that as a result, its manufacturers have not been required to test animals first. But Steven Dentali, VP of science at the AHPA, says the real reason is “a lack of economic incentive, because ginkgo is a natural product and largely unbranded.”

Cheap and easy memory boosters

“While there is essentially little if any evidence supporting the claim that gingko actually improves memory in human beings, there are many other things, very common substances and very common events in peoples’ lives, that actually enhance our ability to remember,” says Ferris.

Light exercise, even just squeezing something like a stress ball, can elevate the levels of certain chemicals in your brain that are important to memory formation. So can having an emotional experience, both positive and negative. For instance, hearing an exciting story can release a neurotransmitter called epinephrine into one’s circulation, which enhances memory without any drugs. In both cases, moderation is the key, as too much exercise or emotion can actually inhibit memory.

Furthermore, if your blood sugar is low there is something you can buy at the supermarket that might tweak your memory a bit--candy. “There is actually good evidence that having a candy bar or just having a sweet drink with sugar in it improves your ability to remember if your blood sugar levels are low,” says Ferris. He points out that studies have shown that people who got a drink with glucose in it performed better on a memory test than those who got a placebo. (He also points out that this needs to be considered in moderation as well: “People shouldn’t be filling up on sugar thinking it’s going to help their memory,” adding that this has its biggest effect when blood sugar levels are low.)