Which components of the Mediterranean diet are associated with dementia? A UK Biobank cohort study.
Level 3 - non-randomized controlled study
Prospective observational cohort study
PubMed 35794436 · doi:10.1007/s11357-022-00615-2
What was done
The authors examined 249,511 UK Biobank participants aged 55 years or older without dementia at baseline, recruited between 2006 and 2010 and followed until December 2020 (median follow-up 11.4 years; 2,868,824 person-years). Self-reported consumption of Mediterranean diet food groups—including fruit, vegetables, fish, cheese, wholegrains, processed meat, unprocessed red meat, and unprocessed poultry—was assessed. Incident all-cause dementia was ascertained via linkage to primary care, hospital, and mortality records or self-report. Models were adjusted for covariates and other food groups.
What was found
Moderate fish consumption (2.0 to 3.9 times/week) was associated with decreased dementia risk compared to no consumption (HR 0.84, 95% CI 0.71–0.98). Fruit consumption of 1.0 to 1.9 servings/day was also associated with reduced dementia risk compared to no consumption (HR 0.85, 95% CI 0.74–0.99). No other evaluated Mediterranean diet components were statistically significantly associated with dementia risk.
Why it matters
This study evaluates individual Mediterranean diet components, suggesting that the diet's cognitive associations may be driven specifically by moderate fish and fruit intake rather than the overall dietary pattern.
Limits
Diet was assessed via baseline self-report, risking recall bias and failing to capture dietary changes over 11.4 years of follow-up. As an observational study, residual confounding remains possible, and the UK Biobank is subject to healthy volunteer selection bias.