The Associations between a Capsaicin-Rich Diet and Blood Amyloid-β Levels and Cognitive Function

Background: Capsaicin-rich diets are common worldwide. Capsaicin has been shown to have favorable effects on various diseases including atherosclerosis, cardiovascular diseases, stroke, obesity, hypertension, cancer, and gastrointestinal and inflammatory diseases. The impact of capsaicin on Alzheimer's disease (AD), which is the most common form of dementia in the elderly, remains unknown. Objective: To investigate the correlations of capsaicin intake with cognition and blood markers of AD. Methods: A total of 338 participants aged 40 years or older were enrolled from communities. Dietary habits regarding chili pepper consumption were collected using a Food Frequency Questionnaire (FFQ). Cognitive function was measured using the Chinese version of the Mini-Mental State Examination (MMSE). Blood amyloid-beta (A beta) 40 and A beta(42) were measured with ELISA kits. Results: In univariate analysis, MMSE scores (r = 0.209, p < 0.001), serum A beta(40) levels (r = -0.149, p = 0.006), the ratio of A beta(42)/A beta(40) (r = 0.11, p = 0.043) and total serum A beta levels (r = -0.097, p = 0.075), but not serum A beta(42) levels (r = 0.17, p = 0.757), were significantly correlated with total capsaicin diet scores. In multivariate analysis, total capsaicin diet scores were positively associated with MMSE scores and inversely associated with serum A beta(40) levels, and total serum A beta levels, but not serum A beta(42) levels and the ratio of A beta(42)/A beta(40), after adjustment for age, gender, educational level, smoking history, alcohol consumption, body mass index (BMI) and comorbidities. Conclusion: These findings suggest that a capsaicin-rich diet may exert favorable effects on AD blood biomarkers and cognitive function in middle-aged and elderly adults.