Taking vitamin B12 and folic acid supplements may not reduce the risk of developing memory and thinking problems in older people, a new study finds.
Some previous studies had suggested a link between low levels of certainB vitamins and poor thinking skills, but other studies found mixed results about whether boosting B vitamin levels would actually improve cognitive performance.
In the new study, the researchers looked at the effects of taking supplements of two B vitamins for two years in nearly 3,000 healthy people who did not have a vitamin deficiency. All of the participants had high blood levels of a protein building block called homocysteine, which has been linked to an increased risk of memory loss and Alzheimer's disease.
"Since homocysteine levels can be lowered with folic acid and vitamin B12 supplements, the hope has been that taking these vitamins could also reduce the risk of memory loss and Alzheimer's disease," study co-author Rosalie Dhonukshe-Rutten, a researcher at Wageningen University in the Netherlands, said in a statement.
The study participants were 74 years old on average, and were randomly assigned to two groups. One group took vitamin B12 and folic acid (vitamin B9) supplements, and the other group took a placebo. The participants took tests to measure their attention and memory skills, including their working memory, which is the type of memory people use to perform daily tasks. [6 Foods That Are Good For Your Brain]
The results showed that the people who took the B vitamins had decreased levels of homocysteine over the study period. However, the test scores didn't differ between the two groups, suggesting the supplements didn't affect people's thinking performance, according to the study, which was published today (Nov. 12) in the journal Neurology.
"While the homocysteine levels decreased by more in the group taking the B vitamins than in the group taking the placebo, unfortunately, there was no difference between the two groups in the scores on the thinking and memory tests," Dhonukshe-Rutten said.
However, the researchers noted that the people who participated in the study were healthy, and the effects of vitamin B supplements may be different for people who already have cognitive problems. Also, vitamin levels could be linked to changes in the brain that are not translated to psychological tests but could be seen on brain scans, they said.
For people in developed countries, a normal diet is often sufficient to provide the body with all the vitamin B12 that it needs. Meat, fish, eggs and dairy products are rich in this vitamin. Symptoms of a vitamin B12 deficiency can include weight loss, poor memory and neurological signs, but these symptoms can also be caused by other conditions.