For Patients With Alzheimer's, Vitamin B Supplementation Does Not Slow Cognitive Decline

For patients with mild- to moderate- Alzheimer's disease, cognitive
decline was not slowed by the administration of high-dose vitamin B
supplementation in an article released on October 14, 2008 in JAMA.




Alzheimer's Disease (AD) is a degenerative neurological disease that is
a common form of dementia. There has been evidence that an amino acid
naturally produced in the body, homocysteine, is present in higher
levels in cases of Alzheimer's patients, and homocysteine's
relationship to various neuropathological mechanisms suggests that
reducing its levels may alter the course of the disease. According to
the authors, B vitamins that influence metabolism of homocysteine have
been considered to this end, but previous studies have not yet had
sufficient size or duration of follow-up to actually assess their
effects on this cognitive disorder.



To investigate the potential of B vitamins in Alzheimer's treatment,
Paul S. Aisen, M.D., of the University of California, San Diego, and
colleagues, examined 409 individuals in a randomized controlled trial.
One group was supplemented with folic acid (5 mg/d of folate,) vitamin
B6 (25 mg/d of vitamin B6,) and vitamin B12 (1 mg/d of vitamin B12) for
18 months. The second group was treated with a placebo. The patients
were medicated throughout the study and were tested for their cognitive
abilities using the Alzheimer Disease Assessment Scale (ADAS-cog).



It was found that the vitamin supplement was linked to a reduction in
homocysteine levels in the blood plasma. however, when examined in
light of cognitive testing, ADAS-cog scores did not differ
significantly between the two treatment groups. Notably, depression
symptoms were more common in the supplemented group.



The authors conclude that, while homocysteine levels dropped in the
supplemented patients, but this did not improve cognitive outcomes:
“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.”



High-Dose B Vitamin Supplementation and Cognitive Decline in
Alzheimer Disease: A Randomized Controlled Trial

Paul S. Aisen; Lon S. Schneider; Mary Sano; Ramon Diaz-Arrastia;
Christopher H. van Dyck; Myron F. Weiner; Teodoro Bottiglieri; Shelia
Jin; Karen T. Stokes; Ronald G. Thomas; Leon J. Thal; for the Alzheimer
Disease Cooperative Study

JAMA. 2008;300(15):1774-1783.

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Written by Anna Sophia McKenney