B12 shortage linked to cognitive problems
Studies in elderly show that even 'normal' levels of vitamin may not be enough
By Janet Raloff
Not getting enough vitamin B12 may take a serious toll on the brain. Two new studies of the elderly link impairments of memory and reasoning with an indirect measure of vitamin B12 deficiency. Worse, brain scans reveal that those with signs of insufficient B12 are more likely to have shrinkage of brain tissue, vascular damage and patches of dead brain cells than are people with higher levels of the vitamin.
A third, ongoing study is recording neural changes — a slowing in the electrical signals conveying visual information — among people with B12 deficiency.
Conducted in seniors, mostly in their mid-70s to upper 80s (including a large group in Chicago), all three studies observed adverse changes even in people whose B12 levels in blood fall within the ostensibly normal, healthy range. While blood levels of B12 might have been normal, however, two biochemical markers of B12 deficiency often were not: Except in the visual study, brain problems largely correlated with rising blood concentrations of homocysteine and methylmalonic acid, or MMA, which accumulate in blood when cells of the body receive too little B12.
“The message of this Chicago study is watch your B12. It’s important for the brain,” says David Smith of the University of Oxford in England, whose team has begun investigating whether vitamin supplementation can slow cognitive decline in the elderly.