Aging: Lack of B12 Linked to Brain Shrinkage

By NICHOLAS BAKALAR

Published: September 8, 2008

Failure to properly absorb vitamin B12, found in meat, milk and eggs, has been implicated in various neurological disorders. Now a British study suggests that low levels of the vitamin in older people may cause the brain to shrink.

Vitamin B12 Status and Rate of Brain Volume Loss in Community-Dwelling Elderly (Neurology)

The study, published Tuesday in Neurology, included 107 men and women, average age 73, who had no mental impairments. Researchers used M.R.I. scans to measure brain volume and blood tests to record vitamin B12 levels. They divided the subjects into three groups, based on their level of the vitamin, and followed them for five years with annual scans and physical and mental examinations.

The group with the lowest levels of vitamin B12 lost twice as much brain volume as those with the highest levels. The difference was significant even after controlling for initial brain size, age, sex, education, cognitive test scores and various measures of blood chemistry.

David Smith, an emeritus professor of pharmacology at Oxford and the lead author of the study, said the work established an association, but not a causal connection.

“This doesn’t mean you should go out and buy vitamin B12 tablets tomorrow,” he said. “We need to know the results of a clinical trial in which we’re testing whether B12 does actually prevent brain shrinkage.”