The how and when
Researchers invited 4,447 French adults, who were 45 to 60 years old at the time of enrollment into the study, to look at the connection between dietary supplements and maintaining memory over time.
Participants were randomly selected to receive one of the following daily for eight years: a supplement containing 120 mg of vitamin C, 6 mg of beta carotene, 30 mg of vitamin E, 100 mcg of selenium, and 20 mg of zinc, or a placebo with no active ingredients.
Approximately six years after the end of the study, participants completed tests of thinking (cognitive) ability to assess:
- Overall memory
- Verbal memory: the ability to recall words and phrases when asked to do so, and
- Executive function: the ability to organize thoughts, prioritize tasks, and make decisions
The tests revealed that compared with the no antioxidant group, those who received daily antioxidant supplements had significantly better verbal memory. The researchers noted that antioxidant supplements improved verbal memory only in people who were nonsmokers or who had low vitamin C blood levels at the start of the study.
What do these findings mean for you?
While interpreting these results, it is important to note the important conclusions the authors draw from the study results:
- Adequate antioxidant nutrient status may preserve verbal memory under certain conditions. Status does not mean taking supplements; it means getting enough antioxidants in your diet through food, supplements, or a combination of the two.
- Antioxidant supplements were significantly associated with better verbal memory in nonsmokers only; there was a hint of harmful effects of the supplements in smokers.
- Antioxidant supplements were associated with better verbal memory most strongly in participants who had a low vitamin C blood levels at the start of the study.
- The results support a beneficial effect of a well-balanced intake of antioxidant nutrients at nutritional doses. Nutritional doses are those you can get from food. You can take a pill, but eating the right foods also will get your body and brain the antioxidants (and other nutrients) needed to stay healthy.
The take-home message is clear. Antioxidant supplements may be helpful, but only if you don't smoke and, in particular, when you may not be getting enough of these nutrients from food alone. And plenty of other studies support the beneficial effects of getting your antioxidants from plants: vegetables, fruit, whole grains, legumes, nuts, and seeds.
If you suspect your diet isn't giving you enough antioxidants for good health, talk to your doctor or dietitian about whether a supplement is right for you. Keep in mind, if you smoke, antioxidants supplements of any kind may do more harm than good.
(Am J Clin Nutr; published online ahead of print July 20, 2011, as doi: 10.3945/ajcn.110.007815)