Vitamin B supplementation did not slow cognitive decline in patients with Alzheimer disease

Oct 14, 2008

High-dose vitamin B supplementation for patients with mild to moderate Alzheimer disease did not slow the rate of cognitive decline, according to a study in the October 15 issue of JAMA.

Evidence of homocysteine (an amino acid produced by the body) elevation in Alzheimer disease (AD) and the involvement of homocysteine in neuropathological mechanisms suggest that reduction of homocysteine may offer an approach to altering the disease. B vitamins that influence homocysteine metabolism have been considered as a therapeutic option to reduce risk of AD or slow its progression, according to background information in the article. According to the authors, prior studies of B vitamins to reduce homocysteine in AD have not had sufficient size or duration to assess their effect on cognitive decline.

Paul S. Aisen, M.D., of the University of California, San Diego, and colleagues conducted a clinical trial to determine if reduction of homocysteine levels with high-dose supplementation with folic acid and vitamins B6 and B12 for 18 months would slow the rate of cognitive decline in 409 individuals with mild to moderate AD. Participants were randomly assigned to two groups of unequal size to increase enrollment (60 percent treated with high-dose supplements [5 mg/d of folate, 25 mg/d of vitamin B6, 1 mg/d of vitamin B12] and 40 percent treated with identical placebo). A total of 340 participants (202 in active treatment group and 138 in placebo group) completed the trial while taking study medication. Cognitive abilities were measured via testing with the Alzheimer Disease Assessment Scale (ADAS-cog).

The researchers found that even though the vitamin supplement regimen was effective in reducing homocysteine levels, it had no beneficial effect on the primary cognitive measure: the rate of change in ADAS-cog score did not differ significantly between treatment groups. The authors did find that symptoms of depression were more common in the high-dose supplement group.

"Many studies suggest that relative elevation of homocysteine is characteristic of AD, and laboratory research implicates homocysteine in neurodegenerative mechanisms. High-dose B vitamin supplementation in individuals with normal levels of B vitamins was effective in reducing homocysteine levels. However, our study does not support the treatment of individuals with mild to moderate AD and normal vitamin levels with B vitamin supplements," the authors conclude.

Citation: JAMA. 2008;300[15]:1774-1783.

Source: JAMA

Explore further: US scientists make embryonic stem cells from adult skin

add to favorites email to friend print save as pdf

Related Stories

Genetic variants associated with vitamin B12

Sep 08, 2008

Researchers at the Harvard School of Public Health (HSPH) and their collaborators at Tufts University and the National Cancer Institute (NCI) have identified a common genetic influence on B12 vitamin levels in the blood, ...

Recommended for you

Leeches help save woman's ear after pit bull mauling

11 hours ago

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

New pain relief targets discovered

23 hours ago

Scientists have identified new pain relief targets that could be used to provide relief from chemotherapy-induced pain. BBSRC-funded researchers at King's College London made the discovery when researching ...

User comments : 0

More news stories