Low levels of vitamin B12 may put older people at risk for cognitive decline. Researchers in Chicago studied more than 500 volunteers for over six years. Their mental function was assessed through testing every three years. Blood samples were analyzed for vitamin B12, homocysteine and methylmalonic acid. People with low levels of B12 and high levels of methylmalonic acid, a marker of intracellular vitamin B12 insufficiency, had a more rapid decline in their test scores. Those subjects with higher levels of B12 did better.
Senior citizens can develop vitamin B12 deficiencies over time as a result of too little stomach acid. Drugs that suppress the production of stomach acid have been linked to lower levels of this nutrient. A diabetes drug called metformin is also associated with vitamin B12 deficiency. Physicians need to monitor both B12 and methylmalonic acid to best make sure that older patients are not put at unnecessary risk of cognitive decline.
[Neurology, Sept. 27, 2011]