Media Reports Miss Research Flaws

Recent studies have cast doubt on the efficacy of ginkgo, an ancient Asian remedy and one of the best-selling herbs here in America, specifically with regard to its ability to fight dementia and sharpen cognitive function. Though one study grabbed lots of media attention, when I asked Daily Health News contributing medical editor, Andrew L. Rubman, ND, about it, he said the study was a poor demonstration of ginkgo’s medicinal effects and notes that it stands in stark contrast to prior research. Believing strongly that proper use of ginkgo is valuable for many medical challenges, including dementia prevention, Dr. Rubman continues to prescribe it for many of his patients and says they have experienced excellent results.

RESEARCHERS DIDN’T PAY ATTENTION

In the Ginkgo Evaluation of Memory (GEM) study, research teams at five US medical academic centers followed 3,069 participants age 75 or older for approximately six years. At the beginning of the study, all either had normal cognition or mild cognitive impairment that did not interfere with their ability to live normal lives. Participants were randomly assigned to take either 120 milligrams of ginkgo twice daily or to take a similar-appearing placebo. Over time, 277 in the ginkgo group and 246 in the placebo group were diagnosed with dementia. Based on these summary numbers the Journal of the American Medical Association study reported that ginkgo did not reduce the overall incidence of dementia or Alzheimer’s disease in older people.

However, Dr. Rubman enumerated a variety of limitations in the study, which he believes wrongly influenced its conclusions. For instance, he notes that…

  • While the study did use at least 240 mg/day in divided doses, as is recommended for a potent standardized material — in truth, older people need nearly twice this amount to achieve clinical effects, Dr. Rubman says. For such patients, he routinely prescribes doses approaching 500 mg/day of ginkgo.
  • Not all ginkgo is created equal. The study utilized a standardized extract, EGb-761, which contains 24% flavone glycosides and 6% terpene lactones, but the research does not compare this to different formulations of ginkgo. Dr. Rubman generally prescribes whole leaf concentrates which he finds to be more effective.
  • Given that it is a “memory” study, the absence of verification that all of the participants consistently took the supplements raises questions.
  • The study is in direct contrast to more than 50 other studies and reports published in respected journals, including the Archives of Neurology (1998) and JAMA (1997), demonstrating that ginkgo boosts cognitive function and fights dementia.
  • The study failed to report other lifestyle factors that could nullify benefits of ginkgo. In addition, patients over age 75 might experience other aging-related physiological changes that may influence cognition.

HOW GINKGO BOOSTS BRAIN FUNCTION

Ginkgo bolsters brain function through very specific biological processes, Dr. Rubman explains, which include antioxidant and anti-inflammatory effects on the nervous and circulatory systems. Helpful to all of us, this is especially beneficial to those who are experiencing early signs of dementia (confusion, agitation or mood swings, social withdrawal, memory loss, unclear thinking, etc.) because it may reduce the frequency or intensity of such disturbances. In particular, says Dr. Rubman, ginkgo exerts a powerful neuroprotective effect on the brain by…

  • Acting as an antioxidant to wipe out free radicals that can otherwise lead to inflammation and disease and increase the symptoms associated with dementia.
  • Stimulating the reception of important chemical messengers in the brain known as neurotransmitters. According to one study in Neuropsychopharmacology, changes in serotonergic function may influence Alzheimer’s disease and cognitive impairment.
  • Keeping blood vessels and capillaries flexible, which improves the flow of blood and oxygen to the brain.
  • Supporting healthy circulation by inhibiting the blood-clotting effects of platelet aggregation.
  • According to the Physician’s Desk Reference for Herbal Medicines, antioxidants in ginkgo prevent lipid peroxidation. Lipid peroxidation can cause vascular damage and neuronal loss.

STILL A VALUABLE TREATMENT OPTION

Results of this study notwithstanding, Dr. Rubman remains convinced that ginkgo is a well-tolerated and effective supplement. Of course, it is always best to see a practitioner who is trained and experienced in botanical medicine to ensure you are receiving the proper type of ginkgo and dosage.