Vitamin B12 for cognition.

Study answer

What this study found

Overall, vitamin B12 supplementation did not show convincing improvement in cognitive function in older adults with dementia or low B12. The clearest trial results were null for ADAS-Cog in Alzheimer disease (MD 0.04, 95% CI -5.95 to 6.03, p=0.99) and null for MMSE after 1 month with oral cyanocobalamin 10 microgram daily (MD -1.60, 95% CI -3.99 to 0.79, p=0.19) or 50 microgram daily (MD -0.60, p=0.63). In the 3-month deficiency trial, CAMCOG was also null (MD -0.6, 95% CI -2.2 to 0.9, p=0.43) and MMSE was unchanged (MD 0.1, 95% CI -0.6 to 0.8, p=0.70), with no adverse events reported. A…

Study & population

Systematic review of 3 small randomized trials in older adults, mainly people with dementia, cognitive impairment, or low/subnormal serum vitamin B12 levels.

Intervention

Vitamin B12 was given in several regimens across the included trials: 1000 microgram injections daily for 5 days, then one injection monthly for 5 months; oral cyanocobalamin 10 microgram daily for 1 month; oral cyanocobalamin 50 microgram daily for 1 month; and 1 mg cyanocobalamin injections weekly for 4 weeks.

Key limitation

The evidence base was very small, with only 3 trials and limited active-arm sample sizes, including one arm with N=5.

View full study detailsView sourceOpen PDF

Original abstract