Fixing a borderline-low B12 level did not sharpen thinking
Over 27 months, 271 older adults with diabetes and borderline-low B12 took 1000 micrograms a day. The shortage markers fell; dementia ratings and test scores did not move.
What the study found
The markers corrected and the memory tests did not follow
Over 27 months, 271 older adults with diabetes and borderline-low B12 took methylcobalamin 1000 micrograms a day or a placebo. Methylmalonic acid and homocysteine, which rise when cells run short, fell significantly in the treated group. Neither dementia ratings nor test scores moved.
The caveat · 44% started with possible dementia
All of them were older outpatients with diabetes, many on metformin, so this is not a general older-adult sample. Forty-four percent already had questionable dementia at the start, which may put some of the decline beyond reach. Borderline-low is not outright deficiency.