All antioxidants are not created equal when it comes to reducing the risk of stroke and dementia, according to a new study from the Netherlands.
The study, published in the journal Neurology, found no association between the total intake of antioxidants and a lower risk of these brain diseases.
Antioxidants have been touted for their ability to reduce a number of health risks, leading many people to indulge in antioxidant-rich foods like blueberries and chocolate and take high potency supplements.
Past research has found that a diet high in vitamin C was associated with a lower risk of stroke and high vitamin E intake was associated with a lower incidence of dementia. But these studies don’t address the benefits of a generally healthy antioxidant-rich diet.
This study involved 5,395 adults age 55 and older who had no signs of dementia at the start of the study. Participants completed dietary questionnaires and were followed for an average of 14 years.
Three groups emerged: those with low, moderate and high levels of antioxidants in the diet.
About 90 percent of the difference in antioxidant levels was attributed to the amount of coffee and tea people drank. Coffee and tea contain high levels of flavonoids.
About 600 people developed dementia, and about 600 had a stroke during the follow-up period.
Researchers found those who consumed the most antioxidants had the same risk of stroke and dementia as those who ate the least antioxidants.
“Other studies have suggested that antioxidants may help protect against stroke and dementia,” said study author Dr. Elizabeth Devore, of Harvard Medical School and Brigham and Women’s Hospital in Boston. “This study suggests that we really need to be specific about the antioxidants we’re taking in to reduce dementia and stroke risk.”
There’s a large body of research showing that vitamin C, and a diet high in fruits and vegetables, reduce the risk of stroke. Similarly, a number of studies have found that a high intake of vitamin E lowers the risk of dementia. The adults in this study had a higher intake of vitamin E-rich nut oils and seed oils, but vitamin E is also prevalent in dark leafy greens and other fruits and vegetables.
Previous studies have also found that high flavanoids, the main antioxidant in coffee and tea, do not reduce these risks.
As for the benefits of coffee and tea on the brain: “My guess is that we won’t find much of an association,” Devore said.
Laurie Tarkan is an award-winning health journalist whose work appears in the New York Times, among other national magazines and websites. She has authored several health books, including "Perfect Hormone Balance for Fertility." Follow her on Twitter and Facebook.