Ginkgo biloba is an ancient Chinese herbal remedy that has been shown to have significant neuroprotective effects. However, two recent major studies and a Cochrane review cast doubt on the validity of the prior, smaller and shorter studies, and determined that in the aggregate the data do not support the use of ginkgo in the prevention of Alzheimer's disease. The recent evidence is mostly negative, though the studies are still inconsistent. Although ginkgo has a mild effect in protecting against mild cognitive impairment/dementia, it probably does not prevent it. But all sources except one remain optimistic for some ongoing neuroprotective role for Ginkgo.
Mental Health Implications
Despite the evidence from these studies and review, all sources except Berkeley Wellness remain optimistic for some ongoing neuroprotective role for ginkgo. Pending subsequent studies, the jury is still out on ginkgo and memory/dementia.
Until a scientific and popular consensus emerges, ginkgo will continue to be used as one of the few known neuroprotective CAM treatments for dementia, preventing and treating memory impairment, lack of concentration, and cerebral-vascular insufficiency, as well as age-related and dementia-related cognitive weaknesses.
Rhodiola, SAM-e, folate, omega-3s, and CDP-choline (see those chapters of this outline) may provide alternatives now that ginkgo has been shown to be less effective a remedy than it had long been supposed to be.
No Reason to Stop
The recent negative evidence should lead consumers to question the efficacy of ginkgo to prevent or delay cognitive impairment. However, a single study cannot be viewed as definitive, and ginkgo may be considered as an evidence-based CAM treatment for mild and possibly incipient dementia, albeit apparently with limited preventive benefit in delaying or avoiding some of the symptoms of Alzheimer's disease. If you are using ginkgo and tolerating it well, there is no reason to stop.
Ginkgo is being investigated as adjunctive therapy for schizophrenia and attention deficit hyperactivity disorder (ADHD), for protection against the neural damage caused by antipsychotics, and for the treatment of depression. The Natural Standard also states that "good" evidence demonstrates ginkgo's efficacy in the treatment of "cerebral insufficiency." But these are at best promising practices.
These are all unproven uses, but given ginkgo's relatively low cost and benign risk profile, consumers may well wish to try ginkgo for these conditions. Caution is advisable if ginkgo is used with psychotropic drugs, in the absence of studies validating lack of adverse drug interactions. Adjunctive treatment with antipsychotics requires careful coordination with the prescribing physician.
Ginkgo has anticoagulant effects (though bleeding problems have not been noted in the studies), may increase blood concentrations of some drugs used for treating hypertension, may affect insulin and blood sugar levels, and may affect blood pressure. Potential interactions with MAOI, SSRI and antipsychotic drugs have been noted, but have not yet been confirmed in humans. The prescribing physician should be consulted before using ginkgo in connection with these drugs.
According to Mischoulon and Rosenbaum, ginkgo "has an excellent safety record; and except for the assumed possible risk of hemorrhage in patients taking anticoagulants, having bleeding disorders, or [about to] undergo surgery, [ginkgo] appears to be very safe." All sources agree that ginkgo appears safe overall and that side effects are rare. It follows that concerns about pregnancy, breast-feeding and child use are minimal.
Berkeley Wellness cautions that commonly available products may be different than the preparations used in clinical studies. EGb 761 is the only preparation of ginkgo that should be used. And tests by ConsumerLab have found problems in some ginkgo products. For instance, in 2008, tests on seven of the most popular ginkgo products sold in the United States found that five were contaminated or low in key compounds.
Traditional uses of ginkgo as a neuroprotectant are now in question. The split of the sources confirms that this is a controversial supplement, and the recent evidence, from large-scale, long-term studies, is all negative. But the risk is minimal, and the sources continue to argue that ginkgo has neuroprotective efficacy, even if it doesn't prevent Alzheimer's dementia.
For detailed information on Ginkgo biloba and other treatments, download the full review.