Ginkgo biloba is not effective as a treatment for dementia or Alzheimer's disease, according to the latest results from a major US study.
A 240 milligram (mg) daily dose of the dietary supplement had no effect on the onset of Alzheimer's or dementia, suggest findings published in the Journal of the American Medical Association.
The $30 million (£20.1 million) multi-centre study involved a total of 3,069 participants aged 75 or over with either normal cognition or mild impairment.
Over the course of the study, 246 people in the placebo group were diagnosed with dementia - compared to 277 in the ginkgo biloba group.
Gregory Burke and Jeff Williamson, investigators at the study's Wake Forest University Baptist Medical Centre site, said the results were disappointing and surprising, with Mr Williamson adding that the supplement "had enough promising circumstantial evidence from laboratory and animal studies, and enough safety information, to warrant a full-scale test in humans".
Meanwhile another research team has suggested an ingredient in red wine may hold the key to future Alzheimer's treatments.
Scientists at the Feinstein Institute for Medical Research said high doses of resveratrol may reduce levels of amyloid beta which accumulate in the brains of patients.
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