January 08, 2013

B Vitamins Slow Brain Shrinkage

Homocysteine and Brain Shrinkage:

In our last update we described the remarkable link between homocysteine and brain shrinkage - the higher your blood homocysteine level, the faster your brain shrinks!

This meant that scientists could now design clinical trials with clearly measurable endpoints.

They asked a key question - "Can lowering homocysteine with high dose B Vitamins delay or prevent brain shrinkage?" 


The VITACOG Trial:

VITACOG is a recently completed two year trial of homocysteine-lowering B-vitamins in individuals over 70 years old with mild cognitive impairment (Plos One 2010 8;5(9)).  Participants were given either high dose B-vitamins (0.8 mg folic acid, 0.5 mg vitamin B12 and 20 mg of vitamin B6) or a placebo.  Their rate of brain shrinkage was measured by a series of MRI scans.

Complete scans were available for 83 placebo and 85 treated individuals. Homocysteine levels fell by 22.5% in treated subjects but increased by 7.7% in those given a placebo.

As in earlier studies, higher homocysteine was associated with a faster rate of brain shrinkage.  But brain shrinkage was significantly less (slowed by 30%!) in treated individuals with an initial homocysteine level >9.5 μmol/L.

Remarkably, after treating with B vitamins, those with the highest initial homocysteine levels (>13 μmol/L) had a rate of brain shrinkage 53% lower than the placebo group.


AD Smith Plos One 2010 8;5(9)

("Subtracted" MRI scans over two years showing brain tissue contraction (blue/light blue) in: i) placebo-treated 79 year old with baseline Hcy of 22 and follow up Hcy of 30 μmol/L. ii) B-vitamin treated 72 year old with baseline Hcy of 24 and follow up Hcy of 12 μmol/L.
Image: A.D. Smith et al (2010), PLoS ONE: 5(9)\:e12244)

Lowering Homocysteine Slows Brain Shrinkage:

In summary, VITACOG shows that a combination of high dose B12, folic acid and B6 significantly slows brain shrinkage in patients with Mild Cognitive Impairment and raised homocysteine.

VITACOG has now set the stage for larger and longer trials to study the effects of high dose B-vitamins on conversion rates from Mild Cognitive Impairment to dementia.

In our next update we will consider why lowering homocysteine slows brain shrinkage. Fascinating mechanisms underpin this association.

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