Low vitamin B-12 status and risk of cognitive decline in older adults
Supplementation with B12 and folic acid is a very inexpensive approach with high safety and many potential benefits. The problem is that many physicians still use serum B12 to assess status, and while this is a good marker of on the spot B12, it does not really give a good picture of functional status of B12. Personally, I always look at a patient’s MCV (mean corpuscular volume) level on a standard CBC. While most labs don’t consider it normal until it passes 100, I don’t like to see this value much past the lower 90s.
In this study, I think what was surprising was just how much of an effect B12 had on cognitive decline. Higher levels of MMA or homocysteine (markers of functional B12 status) led to a 50% greater risk of congitive decline. That’s a massive difference.