Adults who took vitamin and mineral supplements for almost a decade performed better on one type of memory test than those who didn't take the supplements, according to a new study from France.
The researchers say the findings suggest that getting enough nutrients could aid thinking and memory skills as people get older. But further studies are needed to confirm the results, they add.
The effect was "nothing wild that you'd say, 'Everybody should take these,'" said Geraldine McNeill, a nutritionist at the University of Aberdeen in the UK.
But McNeill, who wasn't involved in the new study, said some people, especially those who are deficient in vitamins and minerals – might get a memory benefit from boosting the nutrients in their diet.
Emmanuelle Kesse-Guyot of the University of Paris XIII in France and colleagues write that the link between a higher intake of some nutrients and thinking and memory skills has been shown before in so-called observational studies. But those studies can't get at a cause-and-effect relationship.
"The question is, does the cognitive performance depend on the diet, or does the diet depend on the cognitive performance?" McNeill said. It's possible that people who have better thinking and memory skills might pay closer attention to what they're eating," she explained.
To try to get a clearer picture of the association, Kesse-Guyot and her colleagues conducted a study of close to 4,500 French men and women.
Supplements and placebo's compared
In 1994, when the study participants were 45 to 60 years old, researchers split them randomly into two groups. Half of them took a daily supplement that included vitamins C and E, selenium, zinc, and beta-carotene for eight years. The others took a nutrient-free placebo pill each day.
None of the participants knew whether they were taking the vitamin or the sham pills.
When the eight years were up, researchers stopped giving participants their assigned pills, and they could choose on their own whether or not to take vitamin supplements.
Six years after that, the investigators brought them back to the lab for a round of memory tests. The tests included word and number problems to measure different types of memory and "mental flexibility".
While the supplement and placebo groups performed similarly on most tests, the nutrient-boosted participants beat their peers on one test of long-term memory in which participants had to recall words in different categories.
The outcome of the study
"Our results have to be considered carefully," the authors wrote in the American Journal of Clinical Nutrition. Because they did several tests, it's more likely that the one difference they found was due to chance.
Still, they added, the "findings support a beneficial effect of a well-balanced intake of antioxidant nutrients at nutritional doses for maintaining cognitive performance, especially verbal memory."
McNeill said that most people could probably get the vitamin and nutrient doses used in the study through tweaks in their diet, for example, drinking fruit juice to get Vitamin C and using plant oil, which is a good source of Vitamin E.
"Taking supplements for me is a last resort," she said.
Barbara Shukitt-Hale, a nutrition researcher at Tufts University in Boston, said it's important for people to know that boosting brainpower requires more than just taking a vitamin pill every day.
"Vitamins and minerals are important for memory, but they're not the only thing that's important," she said. "The most important thing is eating a healthy diet, being active, and keeping your brain sharp."
(Reuters Health, Genevra Pittman, July 2011)