Alzheimer’s patients given high-dose vitamin B supplements to decrease levels of homoceyteine saw no improvement in mental decline compared to those given placebo pills, US researchers said on Tuesday.

Alzheimer’s patients have high levels of the amino acid homocysteine in their blood and B vitamins are known to reduce these levels.

The study was led by Dr. Paul Aisen of the University of California San Diego. It involved 409 people with mild to moderate Alzheimer’s disease who were given either high-dose supplements of vitamins B6, B12, and the B vitamin folic acid for 18 months or placebo pills.

At the end of the follow up period, the researchers found no improvement in Alzheimer’s patients. Although the levels of homocysteine decreased, “but it had absolutely no effect on the clinical symptoms of Alzheimer’s disease,” the researchers wrote in the Oct. 15 edition of the Journal of the American Medical Association. Moreover, those given the vitamin supplements unexpectedly experienced greater amounts of depression.

Therefore, people suffering from Alzheimer’s should not take high doses of the vitamins to avoid mental decline, the researchers concluded.

Alzheimer’s is the most common form of dementia in the elderly affecting one in eight people 65 and older and nearly one in two people over 85 and the number is expected to grow as the baby boom generation ages. Currently, about 5.2 million Americans live with the brain disorder, which causes a progressive loss of memory and mental faculties. The sad part is that current drugs do not cure the disease, just ease its symptoms.