The herbal supplement ginkgo biloba, taken by many people with epilepsy to boost memory, may not be effective, according to research published in the Journal of the American Medical Association.
Extract from leaves of the tree ginkgo biloba is marketed world-wide as an enhancer of memory and other mental functions.
Researchers at Williams College in Williamstown, Massachusetts identified 230 volunteers over the age of 60 who were physically and mentally healthy. They gave them 14 tests of learning, memory, and attention and concentration, and had them and their companions (e.g. partners, close friends) rate the participants' mental functions. Participants were then randomly divided into two groups: one to take gingko and one placebo.
The manufacturer claims beneficial effects can be noticed after four weeks. After six weeks, participants in the study retook the 14 standardised tests and they and their companions re-rated participants' mental functions. There were no significant differences between those taking ginkgo and those taking placebo on any of the objective or subjective measures.
Lead author Professor Paul Solomon said:
"Many of our patients and their families who are seen... have asked whether ginkgo could slow or reverse the effects of ageing on memory. Since there were no scientifically rigorous studies of this, we decided to conduct a study of ginkgo on memory.
"The results indicate that when taken following the manufacturer's instructions, ginkgo provides no measurable benefit in memory, attention, or concentration in healthy older adults. We hope others will now further test ginkgo and other vitamins and nutrients to see if they really provide the benefits they claim."