As Alzheimer’s Disease (AD) research progresses, promising treatment methods surface periodically to give older generations hope. While it would be a much greater pleasure to report on a miraculous cure, it is still important to close the door on dead-ends so that resources are not wasted. Two recent studies decisively deflate the claims that ginkgo biloba and growth hormone can combat AD.

Ginkgo biloba is a plant extract with a large following. Approximately $250 million worth is used every year in the United States. Small studies have demonstrated a variety of memory and cognitive benefits, but many doctors were unconvinced of its efficacy. A large study in this month’s issue of The Journal of the American Medical Association, led by Dr. Steven DeKosky from the University of Virginia, found that ginkgo biloba demonstrated no protection against AD.

Dr. DeKosky gathered over 3,000 elderly volunteers and used a double-blind experiment structure to give one half placebos and the other half two 120 milligram doses of ginkgo biloba a day. Over six years of monitoring, the cases of dementia for both groups were tallied. There were actually slightly more AD cases in the ginkgo biloba group: 246 diagnosed in the placebo group and 277 in the ginkgo biloba group.  While this difference is not significant enough to warrant warning labels, it is certainly strong evidence that ginkgo biloba is not an effective protection.

The second hypothesis-puncturing study, appearing in Neurology, was conducted by Dr. Jeffrey Sevigny and a team from Merck Research Laboratories. Dr. Sevigny investigated growth hormone because animal studies have shown that it can reduce amyloid-beta plaque, one of the main suspects for causing AD. He studied over 500 subjects at 45 different sites all over the country, giving them a double-blind dosage for a year.

Growth hormone failed to show any improvement in cognitive scores, functional disability, dementia progression, or overall doctor’s assessment. Some minor side-effects surfaced, so the researchers did not think it was wise to test higher dosages for effect.

It is disappointing that both of these treatments failed to reduce the risk or severity of AD, but each disproven hypothesis helps us narrow down the search. While we wait for an effective medication, there are some simple methods available to reduce the risk of AD, such as regular exercise.