BACKGROUND: Choline and betaine are linked to phospholipid and one-carbon metabolism. Blood concentrations or dietary intake of these quaternary amines have been related to the risk of chronic diseases, including cardiovascular disease and the metabolic syndrome. OBJECTIVE: We aimed to determine dietary predictors of plasma choline and betaine among middle-aged and elderly subjects recruited from an area without folic acid fortification. DESIGN: This is a population-based study of 5812 men and women aged 47-49 and 71-74 y, within the Hordaland Health Study cohort. Plasma concentrations per increasing quartile of intake of foods, beverages, and nutrients were assessed by multiple linear regression analysis, and dietary patterns were assessed by factor analysis. RESULTS: Plasma choline was predicted by egg consumption (0.16 micromol/L; P