A new study has found that while a combination of vitamin B12 and folic acid did slightly improve a few markers of cognitive function, there was no statistically significant improvement to the other measures of cognitive function used in the study. The study, published in the journal Neurology, tracked 2,919 people with a mean age of 74.1 for two years; participants received either a tablet containing 500 mcg of B12 plus 400 mcg of folic acid, or a placebo tablet. Over the two years, those taking the B vitamin tablet experienced significantly lower levels of homocysteine, which has been associated with cognitive decline, and a small improvement in the rate of decline of global cognition. The researchers state that the improvement in cognition was too small to be clinically relevant and therefore concluded that supplementing with these B vitamins does not beneficially affect cognitive performance. However, this conclusion should be viewed with caution for the following reasons:
The participants in this study were healthy adults with generally good levels of B vitamins.
Dr. David Smith, a lead scientist involved in previous research which focused on the effects of B vitamins on people with age-related cognitive decline, commented that it was impossible to show that B vitamins help with age-related cognitive decline in the new study since all of the participants were healthy.
Dr. Smith also believes that in order to show a protective effect on healthy individuals, a longer study is needed to allow for enough participants to develop cognitive decline in the first place.
The results are consistent with the possibility that B vitamins slow the rate of cognitive decline in healthy elderly people, and do not provide any strong evidence that these vitamins are ineffective for that purpose.