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Dietary Antioxidants May Not Reduce Risk of Stroke or Dementia

Study contradicts previous reports (Feb. 20)

Contrary to other research, a new study has found that the total level of antioxidants in people’s diets is not related to their risk of developing stroke or dementia. The study was published online in Neurology.

Antioxidants, such as lycopene, beta-carotene, and vitamins C and E, are found in many foods.

“These results are interesting because other studies have suggested that antioxidants may help protect against stroke and dementia,” said author Elizabeth E. Devore, ScD. “It’s 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 aged 55 years and older who had no signs of dementia at enrollment. The participants completed questionnaires about how often they ate 170 foods over the past year; then they were followed for an average of nearly 14 years.

The participants were divided into three groups: low, moderate, and high levels of antioxidants in the diet. About 600 people developed dementia during the study, and about 600 people had a stroke. But researchers found that people with high levels of antioxidants were no more or less likely to develop brain disease than people 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 said.

Source: American Academy of Neurology; February 20, 2013.

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