A large-scale prospective cohort study found that consuming more flavonoid-rich foods was associated with a 28% lower risk of dementia. The association was more pronounced in patients at high genetic risk.
The study analyzed data from 121,986 participants.
The study, published in JAMA Network Open, analyzed date from 121,986 patients, and utilized a novel "flavodiet" score based on the consumption of key flavonoid-rich foods, including tea, red wine, apples, berries, grapes, oranges, grapefruit, sweet peppers, onions, and dark chocolate. Participants in the highest quintile of the flavodiet score consumed a median of 7.1 servings per day of these foods, compared to 1.4 servings in the lowest quintile.
During a median follow-up of 9.4 years, 882 incident dementia cases were identified. The researchers observed that the most significant risk reduction was among participants consuming at least two of the following: five servings per day of tea, one serving of red wine, and 0.5 servings per day of berries.
Methods and Additional Findings
The study analyzed dietary data from UK Biobank of participants aged 40 to 70, recruited between 2006 and 2010. The mean age of participants was 56.1 years, with 55.6% female and 44.4% male. The majority of participants (96.6%) identified as White.
Dietary information was collected using the validated Oxford WebQ, a 24-hour computerized dietary assessment tool. Flavonoid values were assigned to foods and beverages using data from the U.S. Department of Agriculture. The median total flavonoid intake was 792.8 mg/d in the middle quintile.
Genetic risk was determined using a combination of apolipoprotein E (APOE) ε4 genotype and a polygenic risk score. Approximately 27.8% of participants were APOE ε4 carriers. Dementia cases were identified through linkage to hospital inpatient records and death registries.
The study's findings were robust across various sensitivity analyses, including examinations of participants aged 60 years or older at baseline (n = 61,719), those with more than 5 years of follow-up (n = 120,959), and those without a history of stroke (n = 119,053).
The researchers used multivariable Cox proportional hazards regression models, adjusting for various factors including sex, socioeconomic status, education level, race and ethnicity, smoking status, sleep duration, physical activity, body mass index, family history of dementia, stroke history, postmenopausal status, medication use, and chronic health conditions.
Limitations
The authors acknowledged several limitations, including potential measurement errors in self-reported dietary assessments and the possibility of residual confounding. Additionally, the study population was generally healthier than the general UK population, potentially limiting generalizability. The use of health records to identify dementia cases may have introduced bias, as poor cognitive ability has been associated with loss to follow-up.
Authors disclosures can be found in the published study.