Ginkgo: How Sensational Headlines Distorted The Facts On Ginkgo

Last year I told you about a widely reported study that found ginkgo biloba extract (GBE) to be ineffective in enhancing memory or cognitive functions.

Many news reports treated that research as if it were the last word on ginkgo biloba extract (GBE), in spite of the fact that a casual look at the details revealed the obvious flaws in the study. But flaws or no flaws, once the headlines announced that ginkgo biloba extract (GBE) didn't provide any benefits, the bell was rung.

They say you can't unring the bell, but the unringing has begun with a new study that makes it clear that the obituaries for ginkgo biloba were premature.

That was then
The most glaring problem with the earlier ginkgo study was the fact that it only lasted six weeks; not nearly enough time to sufficiently judge the effectiveness of a herbal supplement.

In that study, researchers at Williams College in Williamstown, in the US, tested 230 men and women, all over the age of 60. Half the group received 40 mg of ginkgo biloba extract (GBE) 3 times per day, and the other half received a placebo. Before, during, and after the trial period, a series of tests were conducted to measure changes in memory, attention and concentration.

Researchers concluded that, 'ginkgo biloba extract (GBE) provides no measurable benefit in memory or related cognitive function to adults with healthy cognitive function.' But that's simply an unfair generalisation for such a short study. Especially given the fact that the subjects received only 120 mg of ginkgo biloba extract (GBE) per day. Most herbalists and medical professionals who use alternative treatments agree that the recommended daily dosage of 120 mg of ginkgo biloba is too low. Many suggest that the dosage should be 240 mg or more per day.

So if you designed a study that used a higher dosage for a much longer period of time, what do you suppose the result might be? If you guessed, 'a measurable benefit in memory or related cognitive function,' you're right.

All in your head
Last month, researchers at the UCLA Neuropsychiatric Institute in the US presented the results of their ginkgo biloba extract (GBE) study at the annual meeting of the Society of Neuroscience. Their trial had its own drawback - the size; only ten subjects were recruited. But the study had two outstanding strengths: the dosage and the duration.

Whereas most previous ginkgo biloba extract (GBE) studies ran twelve weeks or less, the UCLA study lasted a full six months, giving the supplement every advantage to create a positive effect. And instead of the standard recommendation of 120 mgs per day, the UCLA researchers gave four of their ten subjects 240 mg per day. The other six received a placebo. None of the subjects suffered from dementia, but prior to the study all reported mild memory loss associated with ageing. The average age of the participants was around 60.

The UCLA team tracked the effects of the ginkgo biloba extract (GBE) supplements in two ways. Before and after the trial period, subjects were given cognitive tests. Each subject also underwent magnetic resonance imaging as well as positron emission tomography to track metabolic changes in the brain.

At the conclusion of the trial, the ginkgo biloba extract (GBE) subjects showed a significant improvement in verbal recall tests compared to the placebo group. The two groups didn't differ significantly in brain metabolism changes, although those who showed an improvement in verbal recall tests also experienced an increase in glucose metabolism in the part of the brain that processes visual perceptions related to memory.

Buyer beware
In their report, the UCLA researchers noted that they had used the highest grade of ginkgo biloba extract (GBE) available. They didn't reveal a brand name, but they made the point that the quality of ginkgo biloba extract (GBE) supplements has been shown to vary widely.

This isn't the only concern when you're doing research to decide on a ginkgo biloba extract (GBE) supplement. As I mentioned in another e-Alert, ginkgo biloba extract (GBE) contains a toxic compound called ginkgolic acid which may cause gastrointestinal problems, headaches, and skin irritations for some users. It's generally accepted that 5 ppm is a safe maximum level for this acid. But some manufacturers don't list ginkgolic acid on their labels, so be sure to read content labels carefully.

A member named Jeanette sent in an email and had this to say on the subject of ginkgo biloba extract (GBE) and other herbs: 'As an herbalist, I support the therapeutic use of herbs, but I also emphasise to anyone who will listen that it is important to get competent guidance in the taking of herbs for serious, complicated disorders, and when taking them for a long time.'

And I couldn't agree more. As I've pointed out many times, the effects of all herbal supplements and botanicals should be treated with the same caution you would give to any pharmaceutical. So while this new ginkgo research is both promising and very welcome, those who decide to give ginkgo biloba extract (GBE) a try should do so with care.