Gingko biloba & Ginseng

  • The most convincing study has found no benefit of gingko biloba on cognition in older adults.
  • Previous evidence that gingko biloba can improve memory has been decidedly mixed.
  • The most promising results have occurred with multiple sclerosis patients; there is also some reason to think those with cardiovascular problems may benefit.
  • Gingko biloba is not without side-effects.
  • The quality of the supplements is also probably a factor in determining whether it will be of value.

Most studies supporting the use of gingko have been looking at its use in people suffering from dementia, Alzheimer's, multiple sclerosis etc. That is, not in healthy seniors. There is some evidence that gingko may be helpful with cardiovascular problems and, given recent research that suggests "what's good for the heart is good for the brain", perhaps this is the source of any effects gingko may have on memory and cognitive function.

Gingko can have serious side-effects - those taking other medications, or about to undergo surgery, are advised to tell their doctor if they are taking gingko. There is also some evidence that it may be a danger to unborn children. Nor is it yet clear what the correct dose might be (one study found a beneficial effect at a low dose, but no effect when a higher dose was used!) The quality of the various gingko preparations for sale is also quite variable.

Given these caveats however, some individuals may find gingko helpful - chiefly, it would appear, in terms of a slightly increased alertness. I would speculate that those who do find it helpful are those people whose memory problems are caused by certain cardiovascular risk factors, such as high cholesterol.

Sad to say, another large study has given the thumbs down to ginkgo biloba preventing Alzheimer’s disease.

The randomized, double-blind trial took place over five years, involving 2854 older adults (70+) who had presented to their primary care physician with memory complaints. Half were given a twice-daily dose of 120 mg standardised ginkgo biloba extract and half a placebo.

After five years, 4% of those receiving ginkgo biloba had been diagnosed with probable Alzheimer's disease, compared with 5% in the placebo group — an insignificant difference. There was no significant difference between the groups in mortality, stroke, or cardiovascular events, either.

The French study confirms the findings of an earlier American trial, and is also consistent with another large, long-running study that found no benefits of ginkgo biloba for age-related cognitive decline.

Older news items (pre-2010) brought over from the old website

Ginkgo biloba does not slow rate of cognitive decline

Findings from the large, long-running Ginkgo Evaluation of Memory study have sadly found no evidence for an effect of Ginkgo biloba on global cognitive change and no evidence of effect on specific cognitive domains of memory, language, attention, visuospatial abilities and executive functions. There was also no evidence for treatment effects for any particular group (i.e. by age, sex, race, education, ApoE4 status, or baseline cognitive status). The randomized, double-blind, placebo-controlled clinical trial involved 3069 seniors aged 72 to 96 years, with a median follow-up of 6.1 years. Those taking the herb took a twice-daily dose of 120-mg. Earlier results from the study found Ginkgo biloba did not reduce the incidence of dementia.

[1457] Snitz, B. E., O'Meara E. S., Carlson M. C., Arnold A. M., Ives D. G., Rapp S. R., et al.
(2009).  Ginkgo biloba for Preventing Cognitive Decline in Older Adults: A Randomized Trial.
JAMA. 302(24), 2663 - 2670.

Gingko biloba does not prevent dementia

A six-year study involving over 3000 older adults has found no reduction in the rate of dementia for those taking twice-daily 120 mg doses of Ginkgo biloba.

DeKosky, S.T. et al. 2008. Ginkgo biloba for prevention of dementia: A randomized controlled trial. JAMA, 300 (19), 2253-62.

Daily dose of ginkgo may prevent brain cell damage after a stroke

A study using genetically engineered mice has found that daily doses of ginkgo biloba can prevent or reduce brain damage after an induced stroke. More research is needed before its use in humans can be recommended, but the finding does lend support to other evidence that ginkgo biloba triggers a cascade of events that neutralizes free radicals known to cause cell death.

[1081] Saleem, S., Zhuang H., Biswal S., Christen Y., & Doré S.
(2008).  Ginkgo biloba extract neuroprotective action is dependent on heme oxygenase 1 in ischemic reperfusion brain injury.
Stroke; a Journal of Cerebral Circulation. 39(12), 3389 - 3396.

More study needed to determine if gingko biloba helps memory

A three-year study involving 118 people age 85 and older with no memory problems found no significant difference in the development of memory problems during the study between those who took ginkgo biloba extract three times a day and those who took a placebo. However, when adherence was taken into account, it was found that those who reliably took the supplement had a 68% lower risk of developing mild memory problems than those who took the placebo. But those taking ginkgo biloba were more likely to have a stroke or transient ischemic attack. Further studies are needed.

[1100] Dodge, H. H., Zitzelberger T., Oken B. S., Howieson D., & Kaye J.
(2008).  A randomized placebo-controlled trial of ginkgo biloba for the prevention of cognitive decline.
Neurology. 01.wnl.0000303814.13509.db - 01.wnl.0000303814.13509.db.

Ginkgo may improve executive function in MS patients

A study of 39 MS patients found that those receiving ginkgo biloba were about 13% faster on a Stroop test (measures a person's ability to pay attention and to sort conflicting information). Such a difference would be comparable to differences in scores between healthy people ages 30 to 39 and those ages 50 to 59. The benefit appeared to be greatest for those who had certain problems with the Stroop test.

The study was presented at the American Academy of Neurology's 57th Annual Meeting in Miami Beach, Fla.

Helping memory with "natural" supplements

Do caffeine and glucose help concentration? A recent study found that volunteers who drank a mixture containing caffeine and glucose (as well as trace levels of guarana, ginkgo and ginseng) showed clear improvements in memory and attention. Those who consumed the individual ingredients, or a placebo, did not show such improvements.
Another study by the same researchers found that high doses of lemon balm improved memory and led to greater feelings of calmness in 20 volunteers. The lemon balm was found to increase the activity of acetylcholine – an important chemical messenger which is reduced in people with Alzheimer’s disease.

Scholey, A. & Kennedy, D. 2003. Report at the British Psychological Society Annual Conference in Bournemouth 13-15 March.

Support for gingko biloba

A study of seniors with age-associated memory impairment found significant improvement in verbal recall among those who took gingko biloba for six months. PET scans revealed a correlation with better brain function in key brain memory centers, although there was no detectable changes in brain metabolism. Studies of gingko biloba have had conflicting results, and it is suggested that both length of time (most studies have looked at the effect over 3 months or less) and quality of supplement, may be important.

The research was presented at the annual meeting of the Society for Neuroscience.

Pilot study finds ginseng may improve memory in stroke dementia patients

Following mouse studies showing that ginseng increased the activities of the brain chemicals acetylcholine and choline acetyltransferase, a pilot study of 40 patients (average age 67) with mild to moderate vascular dementia was undertaken by Chinese researchers. 25 patients were randomly selected to receive ginseng extract, while 15 received the drug Duxil® (used to improve memory in elderly dementia patients). Overall, researchers found that patients who took the ginseng compound significantly improved their average memory function after 12 weeks. More research (larger samples, placebo-controls) is needed before this finding can be confirmed.

The study was reported at the American Stroke Association's 28th International Stroke Conference on February 14 in Phoenix.

No support for ginkgo as a memory enhancer

In a double-blind study of 230 healthy seniors, half of whom were given gingko biloba and half a placebo, ginkgo biloba was found to have no beneficial effect on memory and related mental functions after six weeks (the manufacturer claims beneficial effects can be noticed after four weeks).

[494] Solomon, P. R., Adams F., Silver A., Zimmer J., & DeVeaux R.
(2002).  Ginkgo for Memory Enhancement: A Randomized Controlled Trial.
JAMA. 288(7), 835 - 840.

Ginkgo biloba may slow cognitive decline in patients with mild multiple sclerosis

A six-month double-blind, placebo-controlled pilot study of 23 individuals with mild multiple sclerosis found that patients who took the herb Ginkgo biloba performed better on neuropsychological tests compared to those who took the inactive placebo.

Corey-Bloom, J., Kenney, C. & Norman, M. 2002. Paper presented at the annual meeting of the American Academy of Neurology on April 18 in Denver, Colorado.