Methodological approaches to compile and validate a food composition database for methyl-group carriers in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

A standardised methodology was used to compile and validate a methyl-group carrier database (MGDB) including folate, choline, betaine and methionine, for use in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Compilation was performed by following structured guidelines to match the EPIC dietary intake data to food items from four food composition databases, according to their assigned priority of use. To assess relative validity, calculated dietary folate intakes were compared between the MGDB and the EPIC nutrient database (ENDB), used as the reference database.