Homocysteine-lowering by B vitamins slows the rate of brain atrophy

January 01, 0001

Homocysteine-lowering by B vitamins slows the rate of brain atrophy

Homocysteine is a risk factor for brain atrophy, cognitive impairment and dementia. Plasma concentrations of homocysteine can be lowered by dietary administration of B vitamins. The aim of this study by researchers from the UK and Norway was to determine whether supplementation with B vitamins that lower levels of plasma total homocysteine can slow the rate of brain atrophy in subjects with mild cognitive impairment in this single-center, randomized, double-blind controlled trial of high-dose folic acid, vitamins B6 and B12 in 271 individuals (of 646 screened) over 70 y old with mild cognitive impairment. A subset (187) volunteered to have cranial MRI scans at the start and finish of the study. Participants were randomly assigned to two groups of equal size, one treated with folic acid (0.8 mg/d), vitamin B12 (0.5 mg/d) and vitamin B6 (20 mg/d), the other with placebo; treatment was for 24 months. A total of 168 participants (85 in active treatment group; 83 receiving placebo) completed the MRI section of the trial.

The mean rate of brain atrophy per year was 0.76% in the active treatment group and 1.08% in the placebo group (significant). The treatment response was related to baseline homocysteine levels: the rate of atrophy in participants with homocysteine greater than13 µmol/L was 53% lower in the active treatment group (significant). A greater rate of atrophy was associated with a lower final cognitive test scores. There was no difference in serious adverse events according to treatment category.

The researchers concluded: "The accelerated rate of brain atrophy in elderly with mild cognitive impairment can be slowed by treatment with homocysteine-lowering B vitamins. Sixteen percent of those over 70 y old have mild cognitive impairment and half of these develop Alzheimer's disease. Since accelerated brain atrophy is a characteristic of subjects with mild cognitive impairment who convert to Alzheimer's disease, trials are needed to see if the same treatment will delay the development of Alzheimer's disease."

Although shown to not be helpful, so far, for ischaemic heart disease, this is an interesting spin. Long term studies are clearly required.

For the full abstract, click here.

PLoS ONE 5(9): e12244, 8 September 2010 © 2010 Smith et al
Homocysteine-Lowering by B Vitamins Slows the Rate of Accelerated Brain Atrophy in Mild Cognitive Impairment: A Randomized Controlled Trial. David Smith, Stephen M. Smith, Celeste A. de Jager et al. Correspondence to David Smith: [email protected]

Category: N. Neurological, P. Psychological, T. Endocrine/Metabolic/Nutritional. Keywords: homocysteine, vitamin B, brain atrophy, mild cognitive impairment, randomized controlled trial, journal watch.
Synopsis edited by Dr Stephen Wilkinson, Melbourne, Australia. Posted on Global Family Doctor 8 October 2010

Pearls are an independent product of the Cochrane primary care group and are meant for educational use and not to guide clinical care.