High levels of the amino acid homocysteine in blood are a marker for poor vitamin B status and have also been associated with cognitive decline and dementia. This had led to studies investigating whether vitamin B12 and folic acid supplements could improve memory performance and potentially protect against cognitive decline later in life.
A recent review of the latest evidence concluded that vitamin B supplements did not improve memory and thinking in the general older population. However, the studies in that review did not focus specifically on people with high homocysteine, who may be most likely to benefit from supplementation.
In this clinical trial, researchers in the Netherlands studied 2,919 people over the age of 65, who had high homocysteine levels (between 12 and 50µmol/L). Participants were given either a tablet containing high doses of the B vitamins folic acid (400µg) and vitamin B12 (500µg) or a dummy pill. The volunteers took the supplements for two years and underwent memory and thinking tests at the start and end of the trial.
The researchers found that while the vitamin B supplementation was able to reduce homocysteine levels in the volunteers, this did not translate into differences in memory and thinking. Over the course of the study, participants showed a very mild decline in performance on tests of attention, working memory and information processing speed that did not differ significantly between those taking the dummy pill and those receiving supplements. Performance on the MMSE memory test declined slightly more slowly in the group receiving the vitamin B supplements, although the difference was not large enough to rule out being caused by chance.
Dr Eric Karran, Director of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:
“This large trial adds to previous evidence suggesting that while vitamin B supplements can lower homocysteine levels, this does not translate into improved memory and thinking in the general older population. While some previous studies have suggested that high-dose vitamin B supplements could influence brain changes in people with early memory problems, this trial did not look at people who were already experiencing memory decline. Longer follow-up periods would be needed to see whether vitamin B12 or folic acid supplements could slow the more severe memory decline associated with dementia.
“Although this study casts doubt on the use of vitamin B supplements to aid memory, a balanced diet is a good way to keep healthy at all ages. Evidence suggests that we can maintain a healthy brain for longer by keeping a healthy weight, eating a balanced diet, not smoking, staying active, drinking in moderation and keeping blood pressure and cholesterol in check.”