Low vitamin B12 may speed brain shrinkage

Older people with low levels of vitamin B12 may be more prone to age-related memory declines and brain shrinkage. That finding, reported in Neurology, comes from researchers at Chicago''s Rush University Medical Center. They found that older people with blood markers associated with vitamin B12 deficiency had the smallest brains and the lowest scores on tests measuring thinking, reasoning, and memory. The brain naturally shrinks as people age, and it appears that those with the greatest reductions in brain volume are most at risk for Alzheimer''s disease and other age-related dementias. Though the new study doesn''t prove that vitamin B12 deficiency caused those problems, older adults are more likely than younger people to have lower levels of vitamin B12, which is found in foods such as meat, fish, poultry, milk, eggs, and fortified breakfast cereals. Low vitamin B12 levels, as indicated by higher levels of the amino acid homocysteine, was first linked to brain shrinkage in a 2008 study led by Oxford University emeritus professor of pharmacology A. David Smith. Last year, the UK research team also reported findings from a small clinical trial showing that people who took supplements containing vitamin B12, vitamin B6, and folate had less brain shrinkage than people who did not take the supplements. Earlier this month, the group reported that supplementation also appeared to slow cognitive declines in the same group of high-risk patients with early memory loss. The new study included 121 people aged 65 and older living on Chicago''s south side. As part of a larger, ongoing aging and memory study, they underwent brain imaging an average of 4.5 years after taking memory and brain function tests. They also got blood tests to check their vitamin B12 level and markers of vitamin B12 deficiency, including homocysteine and a substance called methylmalonate.