Contrary to previous research, the total level of antioxidants in peoples diets is not related to their risk of developing stroke or dementia, according to a new study.
Antioxidants such as lycopene, beta-carotene and vitamins C and E are found in many foods, according to background information for the study, which is scheduled for publication in Neurology, the medical journal of the American Academy of Neurology.
“These results are interesting because other studies have suggested that antioxidants may help protect against stroke and dementia,” Elizabeth E. Devore, ScD, of Harvard Medical School in Boston and Erasmus Medical Center in the Netherlands, said in a news release. “Its possible that individual antioxidants, or the main foods that contribute those antioxidants — rather than the total antioxidant level in the diet — contribute to the lower risk of dementia and stroke found in earlier studies.”
The study involved 5,395 people ages 55 and older who had no signs of dementia at the start of the study. Participants completed questionnaires about how often they ate 170 foods over the past year at the start of the study. The participants were followed for an average of nearly 14 years.
Participants were divided into three groups based on the amount of antioxidants in their diets. About 600 people developed dementia during the study and about 600 people had a stroke. The researchers found that people in the group with high levels of antioxidants were no more or less likely to develop brain disease than people in the group with low levels of antioxidants.
Devore noted that about 90% of the difference in antioxidant levels in the study was due to the amount of coffee and tea people drank. Coffee and tea contain high levels of nontraditional antioxidants such as flavonoids.
“This differed from an Italian study that found the higher total antioxidant levels were associated with a lower risk of stroke, where the variation from coffee and tea was lower and the contribution from alcoholic beverages, fruits and vegetables was higher,” Devore noted.
The study abstract is available at www.neurology.org/content/early/2013/02/20/WNL.0b013e3182840c84.abstract.