New evidence suggests that eating your fruits and vegetables—and enjoying a glass of wine—can help reduce the risk of Alzheimer's disease and related dementias. A new study from the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University found that higher intake of flavonoids, which are polyphenolic compounds found in plant-based foods, including grapes and wine, was associated with a lower risk of developing Alzheimer's.
Past studies have found evidence of a link between the flavonoids in wine and lower risk of Alzheimer's, but this analysis is supported by a much longer study, adding considerable weight to the data. The study, published in The American Journal of Clinical Nutrition, analyzed data from the Framingham Heart Study (FHS), a long-term ongoing project in Framingham, Mass. Dr. Paul Jacques and his team of researchers examined dietary habits, including flavonoid intake, of 2,800 participants over the course of 20 years.
The study focused on six classes of flavonoids commonly found in Western diets: anthocyanin, flavanone, flavan-3-ol, flavone, flavonol and isoflavone. Researchers created four intake levels based on percentiles: less than or equal to the 15th percentile (low intake), 15th to 30th percentile, 30th to 60th percentile, and greater than 60th percentile (high intake). They used cumulative data from five four-year exams that included food frequency questionnaires, and compared flavonoid intake with onset of Alzheimer's disease and related dementias. Out of the 2,800 participants, 158 eventually developed Alzheimer's disease.
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The results showed that higher long-term intake of flavonoid-rich foods was associated with a lower risk of Alzheimer's disease and related dementia. Particularly, those with low intake of anthocyanins, commonly found in red wine, were four times more likely to eventually develop Alzheimer's disease and related dementias compared to those with a high intake.
"Red wine was a minor contributor to all of the flavonoid classes except for anthocyanins, where it ranked as the fourth-leading contributor to intake," Dr. Jacques told Wine Spectator. He said that moderate red wine consumption, defined by the study as one drink a day for women and two for men, is a good source of proper flavonoid intake, but that it should be coupled with regular consumption of berries.
Observational studies will always have limitations based on questionnaire inaccuracies. Dr. Jacques has tried to tackle confounding variables by adjusting findings for obesity, smoking and exercise habits, as well as other diet-related factors. But he is still not convinced that flavonoids are completely responsible for lower Alzheimer's disease risk. However, he said, the link between Alzheimer's and diet is very strong. The study mentions the popular Mediterranean diet as a great source of flavonoid-rich foods.
"[Diet] is important,” Dr. Jacques said, “as there are currently no treatments for Alzheimer's disease and related dementias."