Ginkgo for Dementia

A supplement with a moderate effect size in dementia trials

STUDY: Gauthier S, Schlaefke S, Clinical Interventions in Aging 2014

STUDY TYPE: Systematic review and meta-analysis

FUNDING: Independent

Background

Ginkgois often used outside the US for dementia, and improved memory in both Alzheimer’s and vascular types in over 15 placebo-controlled trials (80% are positive, and most used the EGb-761 standardized extract). It’s thought to work by improving mitochondrial energy production in neurons, boosting blood flow to the brain, and supporting neuroplasticity in the hippocampus.

This analysis gathers the evidence together.

The Study

• Meta-analysis of randomized, placebo-controlled trials of EGb 761 in patients with Alzheimer’s disease or vascular dementia.
• Seven trials met criteria, covering 2,625 outpatients total.
• Patients took 120 mg or 240 mg of EGb 761 daily, or placebo, for 22 to 26 weeks.

Results

Ginkgo beat placebo on all three outcome domains. Cognition improved (effect size 0.52), as did daily function (effect size 0.44) and global clinical rating (effect size 0.52). These are all moderate effect sizes, similar in magnitude to what’s reported for cholinesterase inhibitors.

The benefit was dose-dependent. Patients on 240 mg did better than those on 120 mg. Five of the seven trials individually showed a cognitive benefit over placebo.

Side Effects

Adverse event rates didn’t differ meaningfully between ginkgo and placebo.

Limitations

While encouraging, the ginkgo trials as a whole are small, heterogeneous, and at high risk of bias.

Practice Implications

1. Few medications in dementia make a meaningful difference. Ginkgo may help mild dementia, but best to get the EGb-761 extract.
2. EGb-761 also has positive trials in tardive dyskinesia and vascular depression.