Does Folic Acid and B12 Reduce the Risk of Memory Loss?

Although some early observational studies have suggested that vitamin B12 and folic acid supplements may reduce the risk of memory loss and improve cognitive performance, new study results in the journal Neurology say it isn’t so.

“Two-year folic acid and vitamin B12 supplementation did not beneficially affect performance on 4 cognitive domains in elderly people with elevated homocysteine levels,” says study author Rosalie Dhonukshe-Rutten, PhD, of Wageningen University in the Netherlands. “It may slightly slow the rate of decline of global cognition, but the small difference reported may be attributable to chance.”
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Dhonukshe-Rutten and her colleagues conducted a double-blind, randomized, placebo-controlled trial to look at the effects of 2-year folic acid and vitamin B12 supplementation on cognitive performance in elderly people with elevated levels of homocysteine. High levels of this amino acid have been linked to memory loss and Alzheimer’s disease.

The trial is one of the largest intervention studies to date that has investigated the effects of long-term vitamin B supplementation on global cognitive function, episodic memory, attention and working memory, information processing speed, and executive functioning in hyperhomocysteinemic elderly people, according to Dhonukshe-Rutten.

The investigators analyzed data from 2,919 participants, with an average age of 74, who had elevated levels of homocysteine. Every day for 2 years, the patients either took a tablet with 400g of folic acid and 500g of vitamin B12 or a placebo. The researchers administered a large set of validated neuropsychological tests at the beginning and end of the study to measure memory and cognitive performance.

The homocysteine levels decreased by a larger amount in patients who were taking the folic acid and B12 as compared to the placebo group, but there was no difference between the two groups in their scores on thinking and memory tests.

“Only a few studies have shown beneficial effects of combined supplementation of folic acid and vitamin B12 on cognitive performance: in elderly people with elevated psychological distress on overall cognitive functioning, immediate and delayed recall, and in elderly people with mild cognitive impairment,” Dhonukshe-Rutten says. “Like our study, most other studies that were performed in elderly people without dementia with a study duration of at least 1 year did not show significant effects of vitamin B supplementation.” She notes that these findings cannot be extrapolated to persons who already have cognitive problems.

Dhonukshe-Rutten and her colleagues look forward to discovering more about how B-vitamins interact with the brain as they continue their research in this area.

“To unravel the effects of B-vitamins, a closer look into early brain pathologies would be useful to uncover subtle effects that are difficult to detect with paper and pencil tests,” Dhonukshe-Rutten says. “Also whole diet studies are needed, as synergy between nutrients seems to be important.”

—Colleen Mullarkey

Reference

van der Zwaluw NL, Dhonukshe-Rutten RA, van Wijngaarden JP, Brouwer-Brolsma EM, van de Rest O, In ’t Veld PH, , et al. Results of 2-year vitamin B treatment on cognitive performance: Secondary data from an RCT. Neurology. 2014 Nov 12. [Epub ahead of print].