Ginkgo biloba has been used medicinally for over 5000 years. Originally extracts were used to treat pulmonary diseases, such as bronchitis and asthma. More recently, however, ginkgo has been favored to prevent memory loss and dementia. It is believed that flavonoids within the plant are responsible for its proposed medicinal effects, with over 40 different flavonoids have been isolated from leaves from the ginkgo tree. Flavonoids are compounds found ubiquitously in plants having varying antioxidant properties. In animal models these compounds appear to alter neuro-communications and protection against neurologic changes associated with aging, however findings in humans are conflicting. Despite being the subject of over 400 clinical investigations, the efficacy of ginkgo in humans is still undecided.
While many of these trials were small, preventing generalizability, a few large randomized controlled trials have been recently published, which question the utility of ginkgo. In 2009, the results were released of a large randomized controlled trial designed to evaluate the effectiveness of ginkgo biloba verse placebo in reducing the incidence of dementia and Alzheimer disease in elderly individuals. The authors followed approximately 3,000 volunteers over the age of 75 for a median of 6 years. Half of the participants were assigned to take ginkgo twice a day and the other half took a placebo. At the end of the trial, no significant difference was noted between those in the ginkgo group and those consuming the placebo. Overall, the study failed to find any decrease in the incidence or rate of progression of dementia or Alzheimer disease associated with daily ginkgo supplements.
Others have found similarly disappointing results regarding ginkgo’s ability to enhance memory. In a randomized double-blinded, placebo-controlled study, researchers investigated the effect of daily ginkgo on memory, attention, and learning in 330 volunteers older than 60. After following participants for 6 weeks, the authors of the study failed to find any difference between those taking the real supplement and those in the placebo group. These findings suggest that when taken following the manufacturer’s instructions, ginkgo fails to provide cognitive benefits.
Proponents argue that these studies were too short to demonstrate the proposed benefit of ginkgo, particularly given the long natural history of dementia. Additionally, some studies have demonstrated slight benefits with ginkgo. One study, which looked at the effectiveness of gingko in decreasing Alzheimer patients’ cognitive decline, found that ginkgo was comparable to donepezil, a commonly used medication for Alzheimer disease.
Although the majority of studies are inconclusive regarding the benefits of ginkgo, they do, however, demonstrate that ginkgo is safe, with few participants experiencing adverse events. Herbal remedies like tea or supplements derived from gingko biloba can have a positive effect on sexual desire and even orgasm. This age-old remedy is known to improve circulation, yet again enhancing sex. Ginkgo is known to interfere with normal blood clotting, so patients on blood thinners, ginkgo should be used with caution.