Taking a daily multivitamin and mineral tablet may slow the gradual cognitive decline that happens naturally as we get older.
At the end of a three-year trial, people who had taken a commercially available multivitamin-mineral supplement had a cognitive age that was 1.8 years younger than those who took a placebo.
“It’s an eye opener,” says Laura Baker at Wake Forest University in Winston-Salem, North Carolina.
The benefits of taking multivitamin pills have been debated among doctors. They were once widely recommended as an “insurance policy” for people with poor diets, based on studies that found those who take them tend to have better health.
But these studies weren’t randomised, placebo-controlled trials – the gold standard for medical evidence – and when such trials were done, they found no benefit from taking supplements for most healthy people. It seemed the earlier results arose because vitamin tablets are more popular with people who look after their health in many other ways.
The latest research is a randomised trial in nearly 2300 people in the US aged between 65 and 100 years old.
Baker and her team began the study because they wanted to see if flavanols, compounds found in chocolate that are claimed to have health benefits, would help delay cognitive decline with age. The trial included a group that took a standard multivitamin and mineral pill as a comparison.
At the start of the trial, the participants did an array of cognitive tests for memory, verbal and number skills over the phone, with the results merged into a single score.
They were then randomly chosen to take either a flavanol supplement, the combined multivitamin and mineral tablet or a placebo once daily for three years. Similar cognitive tests were repeated every year over the three years.
All the groups did somewhat better, on average, after one and two years, while at three years, their scores roughly plateaued. This was probably because over the first two years people were becoming more familiar with how to do the tests, says Baker.
Those who took the multivitamin and mineral supplements scored slightly higher than those who took the placebo tablet, but there was no significant benefit in the flavanol group. It isn’t known which components of the multivitamin and mineral tablet were responsible for the higher cognitive scores.
The benefit from the multivitamin was greater in people with heart or circulatory disease, such as having had surgery to widen the blood vessels to their heart. This may be because “cardiovascular disease has significant consequences for brain health”, says Baker.
“These findings are quite promising and have the potential to have a significant impact on public health,” says Rebecca Edelmayer at the Alzheimer’s Association.
Journal reference: Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, DOI: 10.1002/alz.12767