Vitamin B12 may protect against brain shrinkage

September 12, 2008

As we age our brain shrinks and brain shrinkage is a common symptom of ageing when people hit their 60's. Vitamin B12 may protect against brain volume loss in older people, and ultimately reduce the risk of developing dementia, suggests a new study from the University of Oxford. A previous study published recently online ahead of print in the Journal of Neurology Neurosurgery and Psychiatry found that lacking either of the B-Complex Vitamins B12 and Folic Acid increased the rate of dementia. Also, increased levels of vitamin B12 and other B vitamins were linked with lower levels of homocysteine, an amino acid reported to increase the risk of dementia or cognitive impairment.
     In this newly published study people with higher blood levels of Vitamin B12 were six times less likely to experience brain shrinkage compared with people with lower Vitamin B12 levels. The study followed 107 community-dwelling volunteers aged between 61 and 87, and expands the science behind vitamin B12 levels and brain health. "Many factors that affect brain health are thought to be out of our control, but this study suggests that simply adjusting our diets to consume more vitamin B12 through eating meat, fish, fortified cereals or milk may be something we can easily adjust to prevent brain shrinkage and so perhaps save our memory," said lead author Anna Vogiatzoglou.
"Research shows that vitamin B12 deficiency is a public health problem, especially among the elderly, so more vitamin B12 intake could help reverse this problem."
Vitamin B12, also known as cobalamin, is only found in food of animal origin, including meat, milk and eggs but it is readily available as an inexpensive supplement.
     In the study the researchers collected blood samples to measure levels of vitamin B12, holotranscobalamin (holoTC – the measure of active B12), methylmalonic acid (when this level goes up it means that B12 is going down), total homocysteine, and Folate. Brain volume loss per year was calculated using MRI scans.
     Over five years of study, the researchers noted a greater decrease in brain volume among people with lower vitamin B12 and holoTC levels. Indeed, people with lower levels of B12, defined as blood levels below 308 picomoles per litre, were six times more likely to experience brain shrinkage, said the researchers. “Low vitamin B12 status should be further investigated as a modifiable cause of brain atrophy and of likely subsequent cognitive impairment in the elderly,” stated the researchers.
It is important to note that none of the volunteers were vitamin B12 deficient.
     A University of Oxford study reported in 2007 that increased vitamin B12 levels may reduce the rate of age-related cognitive decline and dementia by 30 per cent.

The study, published in the American Journal of Clinical Nutrition, followed 1648 participants for 10 years and also found that increased levels of the unstable amino acid homocysteine doubled the risk of dementia or cognitive impairment. Previously, epidemiological studies have reported that high levels of the amino acid homocysteine are associated with suspected or confirmed dementia. Indeed, the Framingham study reported that people with homocysteine levels above 14 micromoles per litre of serum had twice the risk of dementia. The new study is published in the September 9th, 2008 issue of the journal Neurology.