Abstract

Gingko biloba has cognitive benefits both in populations suffering from dementia and after acute treatment in healthy volunteers, with some evidence indicating that those with poorer cognitive performance show greater benefit. We have previously found that 1 week of treatment with ginkgo improved attention, memory and mental flexibility in post-menopausal women, but the evidence for any beneficial effects of longer treatment is less well-established. The present study aimed to determine whether cognitive benefits, similar to those previously found after 1 week of treatment, would persist after 6 weeks of treatment, and whether those with poorer cognitive performance would benefit more. In a placebo-controlled, double-blind study, postmenopausal women (aged 51-67 years) were randomly allocated to receive a standardized extract of ginkgo (LI 1370, Lichtwer Pharma, Marlow, UK) (one capsule/day of 120 mg, n = 45) or matching placebo (n = 42) for 6 weeks. According to an established reproductive staging system, subjects were divided into those in the early (Stage +1; mean age 55 years) and late (Stage +2: mean age 61 years) stages of menopause. At baseline and after 6 weeks of treatment, subjects completed tests of mental flexibility, planning, memory and sustained attention, and ratings of mood, sleepiness, bodily and menopausal symptoms. The only significant effects of ginkgo were in the test of mental flexibility, in which there were significant menopausal stage-ginkgo interactions. This was because subjects in Stage +2 required fewer trials to complete the task and made fewer errors after ginkgo treatment, whereas those in Stage +1 showed no benefits. Subjects in Stage +2 had poorer performance at baseline compared to those in Stage +1 both in this task and the test of planning ability. The beneficial effects of ginkgo were limited to the test of mental flexibility and to those with poorer performance.