Assessment of Dietary Choline Intake, Contributing Food Items and Associations with One-carbon and Lipid Metabolites in Middle-aged and Elderly Adults: The Hordaland Health Study.

Background Choline is an essential nutrient for humans and is involved in various physiological functions. Through its metabolite betaine, it is closely connected to the one-carbon metabolism and the fat-soluble choline form phosphatidylcholine is essential for very-low-density-lipoprotein synthesis and secretion in the liver connecting choline to the lipid metabolism. Dietary recommendations for choline are not available in the Nordic countries primarily due to data scarcity. Objective The aim of this study was to investigate the dietary intake of total choline and individual choline forms, dietary sources, and the association of total choline intake with circulating one-carbon metabolites and lipids. Methods We included 5746 participants in the Hordaland Health Study (HUSK), a survey including community-dwelling adults born in 1925-1927 (mean age 72 years, 55% women) and 1950-1951 (mean age 48 years, 57% women). Dietary data was obtained using a 169-item food frequency questionnaire and choline content was calculated using the USDA Database for Choline Content of Common Foods, release 2. Metabolites of the one-carbon and lipid metabolism were measured in a non-fasting blood sample obtained at baseline and association with total choline intake were assessed using polynomial splines. Results The geometric mean (95% prediction interval) energy-adjusted total choline intake was 260 (170, 389) mg/d with phosphatidylcholine being the main form (44%). The major food items providing dietary choline were eggs, low-fat milk, potatoes, and leafy vegetables. Dietary total choline was inversely associated with circulating concentrations of total homocysteine, glycine and serine and positively associated with choline, methionine, cystathionine, cysteine, trimethyllysine, trimethylamine-N-oxide and dimethylglycine. A weak association was observed between choline intake and serum lipids. Conclusion Phosphatidylcholine was the most consumed choline form in community-dwelling adults in Norway. Our findings suggest that choline intake is associated with the concentration of most metabolites involved in the one-carbon and lipid metabolism.