Millions of people take the herbal supplement, hoping that it will cut their risk of developing Alzheimer’s. But a new study suggests that ginkgo biloba is ineffective against dementia or Alzheimer’s disease. Researchers were disappointed by the results of the study. They were hopeful this herbal supplement would work.

The study included more than 3,000 elderly people who were given either the herbal supplement gingko biloba or a placebo for an average of six years. Half of them took twice-daily doses of 120 milligrams of extract from the leaves of the gingko tree and the rest took a placebo. The participants did not have Alzheimer’s at the start of the study. After six years, researchers found no evidence of reducing the overall incidence of either’s Alzheimer’s disease or dementia, according to the study published in the Journal of the American Medical Association. 18 percent of people taking ginkgo biloba were diagnosed with dementia, compared to 16 percent of those assigned to the placebo group. The first group also included 257 cases of Alzheimer's (also known as Senile Dementia of the Alzheimer Type), whereas in the second one there were reported 220 cases of the disease.

“We found that giving a standardized dose of ginkgo biloba over a period of time does not slow down the incidence rate of dementia or Alzheimer's disease,” said the study's lead author, Dr. Steven DeKosky from the department of neurology at the University of Pittsburgh School of Medicine and Medical Center. An editorial accompanying the study warned not only that the extract did not protect people against developing Alzheimer’s disease, but also that it might be harmful. Patients with a cardiovascular disease who took the supplement faced an increased risk of dementia. The study found more hemorrhagic strokes among participants who took the extract, but the researchers said the difference was not statistically significant.

A previous study by researchers at the University of California, San Diego, found no difference in the cognitive decline of Alzheimer’s patients with mild to moderate forms of the condition who took high-dose vitamin B supplements, compared to those taking a placebo. Researchers found that although the supplements reduced the levels of the amino acid called homocysteine, which tends to be higher in people with Alzheimer’s, there was no reduction in disease progression.

According to the estimates of the U.S. National Institutes of Health, there are currently about 4.5 million Americans with Alzheimer's disease. One in 20 people with ages ranging from 65 to 74 and almost half of those with ages over 85 are affected by the terrible condition.

Alzheimer’s is a terminal and degenerative disease for which there is no known cure. The most commonly symptom is memory loss, as well as difficulty to remember recently learned facts. Sometimes, the condition could not be diagnosed for years. The best way to reduce the risk of dementia is to eat a balanced diet, to exercise regularly and to give up smoking and drinking, which influence the development of the Alzheimer’s.