A preliminary study suggests that a regime of high doses of folic acid, B12 and B6 reduces levels of homocysteine in people with mild to moderate Alzheimer’s. A larger study, recruiting 400 participants from all over the U.S., is to be undertaken to assess whether such a vitamin regime can slow the progression of Alzheimer's disease. In the meantime, it is not advised that people take high doses of these vitamins, as there are possible side-effects, including peripheral nerve damage.
(2003). A pilot study of vitamins to lower plasma homocysteine levels in Alzheimer disease.
The American Journal of Geriatric Psychiatry: Official Journal of the American Association for Geriatric Psychiatry. 11(2), 246 - 249.