Reducing Homocysteine Does Not Improve Cognition
Study with vitamin B therapy does not support homocysteine hypothesis of dementia, but does not refute it
WEDNESDAY, June 28 (HealthDay News) -- In healthy older people, B-vitamin therapy to reduce blood levels of homocysteine does not appear to improve cognitive function, according to a study in the June 29 issue of the New England Journal of Medicine.
Jennifer A. McMahon, Ph.D., of the University of Otago in Dunedin, New Zealand, and colleagues studied 276 healthy adults age 65 or older with plasma homocysteine concentrations of at least 13 μmol per liter. During the two-year study, they randomly assigned subjects to receive either a daily homocysteine-lowering supplement containing folate (1000 μg) and vitamins B12 (500 μg) and B6 (10 mg), or a placebo.
The researchers found that the average plasma homocysteine concentration was 4.36 μmol per liter lower in the treatment group than in the placebo group, but found no significant group differences in cognitive function.
"The authors concluded that they could not provide support for the hypothesis that the lowering of homocysteine concentrations with B vitamins improved cognitive performance," states the author of an accompanying editorial. "However, since the trial included too few participants, the duration of treatment was too short, and cognitive-function scores in controls remained intact throughout the trial, it lacked the statistical power to refute the homocysteine hypothesis of dementia."