Flavonoids are natural substances that are commonly found in fruits like pears, apples, and berries, as well as onions, dark chocolate, tea, and wine; they have been associated with a range of health benefits, including reduced inflammation. Now, a new study, published in the American Journal of Clinical Nutrition, suggests that older adults who eat few flavonoids have a higher risk of developing Alzheimer’s Disease (AD) and Alzheimer’s Disease and Related Dementias (ADRD).
"Our study gives us a picture of how diet over time might be related to a person's cognitive decline, as we were able to look at flavonoid intake over many years prior to participants' dementia diagnoses. With no effective drugs currently available for the treatment of Alzheimer's disease, preventing disease through a healthy diet is an important consideration,” said Paul Jacques, senior author and nutritional epidemiologist at the USDA HNRCA."
The scientists analyzed six types of flavonoids and compared long-term (20 years) intake of flavonoids and the number of AD and ADRD diagnoses later in life. They found that low ingestion rates (15%) of three flavonoids was linked to a higher risk of dementia. Conversely, higher flavonoid intake (60%) was linked to much lower dementia rates.
"Tea, specifically green tea, and berries are good sources of flavonoids. When we look at the study results, we see that the people who may benefit the most from consuming more flavonoids are people at the lowest levels of intake, and it doesn't take much to improve levels. A cup of tea a day or some berries two or three times a week would be adequate” said first author Esra Shishtar.
The scientists started analyzing data for patients when they were about 50 years old, which is still not too late for increased flavonoid consumption to make a difference. Says Jacques, “The risk of dementia really starts to increase over age 70, and the take-home message is, when you are approaching 50 or just beyond, you should start thinking about a healthier diet if you haven't already."