NEW YORK - Older adults who took vitamin B12 and folic acid supplements for two years had greater improvements on short- and long-term memory tests than adults who did not take the vitamins, according to the results of a new study from Australia.
The benefits were modest, but encouraging, indicating that the vitamins "may have an important role in promoting healthy ageing and mental wellbeing, as well as sustaining good cognitive functioning for longer on a community-wide scale," Janine Walker, the lead author of the study and a researcher at Australian National University, told Reuters Health by email.
The researchers asked more than 700 people, aged 60 to 74 years, to take a daily dose of folic acid and vitamin B12 or fake pills that resembled the vitamins. The study only included people who showed signs of depression, but were not diagnosed with clinical depression.
The vitamin dose included 400 micrograms of folic acid and 100 micrograms of vitamin B12. The participants didn't know which pills they were assigned to take.
"We felt that older people with elevated depressive symptoms were an important cohort to target given evidence that late-life depression is associated with increased risk of cognitive impairment," Walker said.
After 12 months, there seemed to be no difference between the groups in how well the people scored on mental tests, including memory, attention and speed.
Two years on, however, those who took the vitamins showed larger improvements in their scores on the memory tasks.
The difference in the improvements was small, the researchers write in their study, published in the American Journal of Clinical Nutrition.
For instance, on a short term memory test, those who took the fake pills improved their score from about 5.2 to about 5.5 over the two years. Those who took the vitamins increased their test scores from 5.16 to roughly 5.6.
Short term memory is used to dial a number someone has just told you, while long term memory comes into play when you try to call that number a day or week later.
Joshua Miller, a professor at the University of California, Davis, said it's difficult to translate the memory improvements on the tests into real life benefits. He said it's likely that some people had larger memory improvements, while others benefited very little.
"For any given individual, there may or may not be an effect. But on a population level, a small increase in cognitive function can have very real ramifications on the functioning of the population as a whole and on the costs of healthcare." Miller said.
Miller said it's possible that certain subgroups of individuals might be more likely to benefit from folic acid and B12 than others.
"What I believe the next thing we need to do is (study) the group that is most likely to benefit from this," Miller, who did not participate in this research, told Reuters Health.
UNCLEAR HOW VITAMINS MIGHT WORK
Walker said it's not clear yet how adding vitamins might work to boost brain functioning, and not all studies have agreed upon their benefits.
One idea is that the vitamins reduce the body's levels of a molecule called homocysteine, which is linked to cardiovascular disease and poor cognitive function.
The body uses homocysteine to build proteins, but high levels of it in the blood are associated with heart disease -- and heart disease is linked to mental decline.
The thinking goes that lowering homocysteine could perhaps reduce someone's cardiovascular risk, and in turn affect his mental functioning.
A recent test of folic acid's influence on cardiovascular disease, however, found that in people with high homocysteine levels, the vitamin didn't help prevent thickening of the arteries.
Walker said it will be important to test whether other groups of people, especially those older than the people who participated in this study, could also benefit from taking the supplements.