Researchers examined the long-term relationship between eating foods containing flavonoids and the risk of AD and AD-related dementias (ADRD).
Older adults who consumed small amounts of flavonoid-rich foods, such as berries, apples, and tea, were 2 to 4 times more likely to develop Alzheimer disease (AD) and related dementias over 20 years compared with people whose intake was higher, according to a new study led by scientists at the Jean Mayer USDA Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University.
The study consisted of 2800 people aged 50 years and older. Researchers examined the long-term relationship between eating foods containing flavonoids and the risk of AD and AD-related dementias (ADRD). Although many studies have looked at the association between nutrition and dementias over short periods of time, the study examined the exposure over a period of 20 years, according to the study authors.
Flavonoids are natural substances found in plants, including fruits, vegetables, and plant-based beverages, and are associated with various health benefits, including reduced inflammation.
The researchers found that the low intake of flavanols (apples, pears, and tea) was associated with twice the risk of developing ADRD. Additionally, low intake of anthocyanins (blueberries, strawberries, and red wine) was associated with a 4-fold risk of developing ADRD. Lastly, low intake of flavonoid polymers (apples, pears, and tea) was associated with twice the risk of developing 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,” said Paul Jacques, senior author and nutritional epidemiologist at the USDA HNRCA, in a press release. “With no effective drugs currently available for the treatment of Alzheimer’s disease, preventing disease through a healthy diet is an important consideration.”
Six types of flavonoids were analyzed and compared in long-term intake levels with the number of AD and ADRD diagnoses later in life. The researchers found that the low intake of 3 flavonoid types was linked to higher risk of dementia compared with the highest intake. For example, low intake was equal to no berries per month, roughly 1½ apples per month, and no tea. Further, high intake was equal to roughly 7.5 cups of blueberries or strawberries per month, 8 apples and pears per month, and 19 cups of tea per month.
Study author Esra Shishtar, said that when looking at the findings, it is easier to see that the people who may benefit the most from consuming more flavonoids are those at the lowest levels of intake, and it would not take much to improve their levels with a cup of tea per day or berries up to 3 times per week.
In addition, Jacques said that 50 years of age, the approximate age at which the data were first analyzed for participants, is not too late to make positive dietary changes.
“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,” Jacques said in a press release.
More berries, apples, and tea may have protective benefits against Alzheimer’s. TuftsNow. https://now.tufts.edu/news-releases/more-berries-apples-and-tea-may-have-protective-benefits-against-alzheimer-s. Published May 5, 2020. Accessed May 6, 2020.