As the global population ages, the number of people living with dementia is expected to increase from 50 million to 152 million by 2050. Currently, there is no cure for dementia, making prevention crucial.
Flavonoids are bioactive compounds found in various plant-based foods, including fruits and vegetables. These compounds offer several health benefits, such as reducing inflammation, improving blood vessel function, and potentially promoting the growth of new neurons in the brain.
A recent observational study involving nearly 122,000 adults indicates that a diet rich in flavonoids may significantly lower dementia risk, particularly among individuals with genetic predispositions or other risk factors like high blood pressure and depression.
The research aligns with previous studies that suggest flavonoids may help slow cognitive decline. It suggests that increasing the intake of flavonoid-rich foods could be an effective strategy for reducing dementia risk.
Study Overview
Led by researchers at Queen’s University Belfast in the UK, the study examined the relationship between diet and dementia using data from adults aged 40 to 70 in the UK Biobank. The analysis included participants with valid dietary assessments, ensuring they had realistic energy intakes. Those diagnosed with dementia or who had withdrawn consent were excluded.
The final sample comprised 121,986 adults, 55.6% of whom were female, with an average age of 56. Researchers calculated participants’ adherence to a “flavodiet score” by tracking daily servings of key flavonoid-rich foods, including:
- Tea (black and green)
- Berries (strawberries and blueberries)
- Red wine
- Apples
- Grapes
- Oranges
- Grapefruit
- Sweet peppers
- Onions
- Dark chocolate
The primary focus was on the incidence of all-cause dementia, determined through hospital and death records. Additional analyses considered genetic risk, high blood pressure, and depressive symptoms.
Participants with a high genetic risk for dementia were identified by the presence of the apolipoprotein E (APOE) ε4 genotype or high Alzheimer’s disease-related polygenic risk scores.
Key Findings
During an average follow-up period of 9.2 years, 882 cases of dementia were reported. Those who consumed the most flavonoid-rich foods were more physically active, had a lower body mass index, and faced fewer financial challenges than those with lower intake.
Participants with the highest flavonoid consumption—averaging six additional servings daily—were 28% less likely to develop dementia compared to those with the lowest intake. The risk reductions were even more pronounced in individuals with high genetic risk (43%), hypertension (30%), or depressive symptoms (48%).
Regarding specific foods, consuming at least two of the following daily—five servings of tea, one serving of red wine, or half a serving of berries—offered the greatest protective benefit, lowering dementia risk by 38%.
Excluding tea, red wine, and berries from the flavodiet scores diminished the protective effect, suggesting these foods significantly contribute to reduced dementia risk. Higher intakes of specific flavonoid subclasses—anthocyanins, flavan-3-ols, flavonols, and flavones—were also associated with lower dementia risk.
Expert Commentary
Eliza Whitaker, MS, RDN, a registered dietitian and medical nutrition advisor at Dietitian Insights, highlighted that while the study’s large sample size provides a good representation, it has limitations. The reliance on self-reported dietary data can introduce bias, and the UK Biobank participants tend to be healthier, with fewer non-flavonoid consumers. This makes it challenging to generalize findings to broader populations. Additionally, there may be reverse causation, where individuals who developed dementia altered their diets before symptoms appeared.
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