Flavonoid-Rich Foods Like Berries and Tea May Cut Dementia Risk

People who consume a regular amount of flavonoid-rich food like berries, tea and red wine tend to have a lower risk of dementia, according to a new study.

Published in JAMA Network Open, the study found that people with hypertension, depression and a higher genetic likelihood of developing dementia experienced the most significant reductions in their dementia risk when consuming flavonoid-packed foods.

The researchers posit that the flavonoids may be helping to combat dementia by reducing neuroinflammation and increasing blood flow to the brain.

A cuppa a day keeps the doctor away

To investigate how diets can affect the risk of developing dementia, the international group of researchers first accessed data from the UK Biobank.

They assessed dietary data from 121,986 participants aged between 40 and 70 years who had an average study follow-up time of 9.2 years.

Over this period, 882 of the participants were diagnosed with dementia.

Participants reported an average serving of 4.3 flavonoid-rich foods per day, primarily tea. Those who consumed the most high-flavonoid foods tended to be more physically active and had a lower body mass index.

The participants who consumed an average of five or more servings of flavonoid-rich foods per day had a lower risk of dementia compared to those who ate the least flavonoids.

The researchers concluded that six additional servings per day of flavonoid-rich foods – specifically tea, red wine and berries – was associated with a lower risk of dementia, with the strongest associations observed for tea consumption.

These associations were especially prevalent in participants with a high genetic risk of dementia and those with modifiable risk factors such as depression and hypertension.

The greatest risk reduction was observed in participants who consumed at least two of the following: five servings of tea per day, one serving of red wine and  half a serving of berries. 

While the connection between the foods and the reduced risk of dementia was only observed, not proven, the researchers propose that the flavonoids in the foods and beverages could be acting on the brain by reducing neuroinflammation and increasing blood flow, thereby staving off dementia symptoms.

Tea, wine and dementia

Regular tea drinking has previously been linked to a lower dementia risk in the same Biobank cohort. A 2021 study found that those who drank more than 4 servings of tea per day had a 14% lower dementia risk than those who didn’t drink tea.

There’s less consensus around the effects of red wine, however. Previous research has linked excessive alcohol consumption (of any alcoholic beverage) to higher risks of developing dementia, while one 2020 review noted that light-to-moderate wine consumption didn’t appear to be linked to an increased risk.

The researchers of the current study acknowledged this nuance and clarified that flavonoids from foods, like berries, should be prioritized in any diet promoted to reduce dementia.

“Associations between alcohol intake, depression and dementia are complex and future studies are needed to further understand these findings,” Dr. Amy Jennings, a senior research fellow at Queen’s University Belfast School of Biological Sciences and lead author of the paper, told Technology Networks.

“Moreover, our population-based study cannot identify whether moderate alcohol or anthocyanins in red wine underlie the observed associations. Current UK health guidance recommends that alcohol consumption be reduced as much as possible, particularly in mid-life, to minimize the risk of developing dementia and therefore anthocyanins from other sources such as berries should be prioritized.”

Reference: Jennings A, Thompson AS, Tresserra-Rimbau A, et al. Flavonoid-rich foods, dementia risk, and interactions with genetic risk, hypertension, and depression. JAMA Netw Open. 2024;7(9):e2434136. doi: 10.1001/jamanetworkopen.2024.34136