Flavonoid Intake Associated With Risk For Alzheimer’s Disease

Over the next 40 years experts are projecting that the number of Americans over the age of 65 will more than double, and along with this increase so will the conditions that are associated with aging also increase. 

Alzheimer’s disease is the leading cause of dementia, experts are predicting that there will be 13.8 million people aged 65+ living with this disease in America by 2050. Although AD is becoming increasingly common the exact cause of this disease continues to be elusive but a growing body of evidence suggests that diet may play a role. 

The Mediterranean diet in particular has been shown in several studies to be associated with a reduced risk of cognitive issues which includes AD. This diet is rich in flavonoids, which are naturally occurring chemicals found present in various fruits and vegetables as well as in plant based beverages such as green tea and wine. 

Tufts University researchers have shown that a long term diet full of flavonoid rich foods such as berries, apples, and tea is associated with a reduced risk of developing this debilitating brain wasting disease with no known cure. 

This study examined the intake of 6 different types of flavonoids on 2,801 individuals over a period of almost 20 years. Flavonoid intake was measured using dietary questionnaires which were filled out roughly every 4 years. Overall health of the group was monitored which included rates of AD and related ADRD as well as for Alzheimer’s disease itself. 

“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,” explains senior study author Dr. Paul Jacques, a nutritional epidemiologist.

193 of the 2,801 participants developed ADRD and 158 developed AD during the course of this study; analysis of the relationships in the data revealed that those who consumed low amounts of flavonoids were 2-4 times more likely to develop ADRD. Low intake of anthocyanins was associated with a 4-fold increased risk of ADRD while a low intake of flavonols was associated with twice the risk. 

In this study, low intake was equivalent to consuming no berries, just over one apple, and no tea in 1 month, while high intake was equivalent to consuming roughly 7.5 cups of berries, 8 apples or pears, and 19 cups of tea in 1 month. It appears as if an apple a day really might keep the doctor away, as with AD there is no cure meaning prevention is the key. According to research it appears that a person can make changes to diet late in life and still be effective, the researchers suggest that it is never too late to start making changes even if in the late 50s.

“With no effective drugs currently available for the treatment of Alzheimer’s disease, preventing disease through a [healthful] diet is an important consideration,” explains Dr. Paul 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 [more healthful] diet if you haven’t already.”

This study was not without limitations such as not being able to prove that a low flavonoid intake causes the disease, only that there is an association. Also the study monitored intake through self reported data which may be subject to errors, but the researchers say that questionnaires from the years leading up to a dementia diagnosis were excluded from the data. Participants were all over the age of 50 and of European descent which also limits the generalizability of the study. 

According to another study published in the American Journal of Clinical Nutrition fabulous flavonoids may also help to lower the risk of heart disease and stroke, protect against certain types of cancers, ease symptoms of rheumatoid arthritis, and reduce the risk of developing Parkinson’s disease as well as dementia.

Great choices for obtaining flavonoids include apples, raspberries, blueberries, plums, strawberries, blackberries, cherries, lemons, oranges, yellow peppers, wine, green tea, certain nuts, dark chocolate, and spinach among other brightly colored fruits and vegetables.