UCSD researchers crossed one more possible treatment for Alzheimer’s disease off their list this week in an ongoing quest for new tools to combat the mental illness that has confounded neurologists and drug companies for decades.
The 18-month study found that high doses of vitamin B supplements did not reduce the rate of mental decline among patients. Patients who took a placebo experienced a roughly equal rate of decline.
Scientists have observed protein “tangles,” harmful plaque and unusually high levels of a particular amino acid in the brains of Alzheimer’s patients, but they still have not determined whether these conditions are causes or symptoms of the disorder.
Roberto Velasquez of the San Diego and Imperial Counties chapter of the Alzheimer’s Association said the latest study reaffirms the disease’s complexity.
“There are a number of theories as to the cause of the disease, but nobody really knows for sure,” he said.
The four drugs that have been approved in the United States to treat Alzheimer’s stimulate healthy brain cells to enhance memory, but their therapeutic effects generally fade within 18 months.
Paul Aisen, director of the Alzheimer’s Disease Research Center at UCSD and a lead investigator for the study, said researchers had considered vitamin B as a treatment because of its affordability and ability to reduce levels of the amino acid homocysteine in the brain.
Of the study’s 409 participants, 60 percent received high doses of vitamin B-6, vitamin B-12 and folic acid, another form of vitamin B. The other 40 percent received placebos.
Although patients taking the supplements did experience a decline in homocysteine levels, their scores on metal-skills tests were comparable to those of placebo patients.
In addition, symptoms of depression were more common among patients who took the supplements.
“I do not believe that people should take high-dose B vitamins to treat Alzheimer’s,” Aisen said. “People believe that they should pursue any plausible treatment. This study demonstrates that, in the case of high-dose B vitamins, the risk outweighs the benefit.”
