Researchers at the University of California Los Angeles (UCLA) Neuropsychiatric Institute found significant improvement in verbal recall among a group of people with age-associated memory impairment who took the herbal supplement ginkgo biloba for 6 months when compared with a group that received a placebo.

The UCLA study, released at the annual meeting of the Society for Neuroscience in New Orleans, used positron-emission tomography (PET) and found that for subjects taking ginkgo biloba, improved recall correlated with better brain function in key brain memory centers.

However, actual changes in brain metabolism, measured by PET for the first time, did not differ significantly between the study's two volunteer groups. Researchers noted that although all volunteers taking ginkgo biloba experienced better verbal recall, a larger sample size might be needed to effectively track brain metabolism results.

"Our findings suggest intriguing avenues for future study, including using PET with a larger sample to better measure and understand the impact of ginkgo biloba on brain metabolism," said Dr. Linda Ercoli, lead author of the study and an assistant clinical professor at the UCLA Neuropsychiatric Institute.

Ginkgo biloba is a Chinese herb often used as a dietary supplement to treat memory loss. The UCLA study and previous controlled clinical trials on ginkgo's effects on verbal recall have yielded conflicting results.

"The research also raises questions regarding the significance of supplement quality and treatment duration," said principal investigator Dr. Gary Small, a UCLA professor on aging and director of the Aging and Memory Research Center at the UCLA Neuropsychiatric Institute. "The Food and Drug Administration does not regulate dietary supplements, and the quality of retail supplies varies widely. We used only the highest grade of ginkgo biloba in conducting our research."

Small also noted that the 6-month UCLA study is one of the first to measure the effects of ginkgo biloba over a longer period of time. Most previous studies have measured the effect of the supplement over 12 weeks or less.

The study examined the impact of ginkgo compared to a placebo in 10 patients, aged 45-75, who did not have dementia but complained of mild age-related memory loss. Four subjects received 120 mg of ginkgo twice daily, and six received a placebo.

Researchers used cognitive tests to measure verbal recall and PET to measure brain metabolism before and after the treatment regimen. Magnetic resonance imaging was used to determine regions of interest to be examined by PET.

This article was prepared by Biotech Week editors from staff and other reports.

From Healthy.net