A Human Ileostomy Model to Determine Folate Bioavailability from Food

Abstract

Results from a pilot study are presented, when under strictly standardized procedures two ileostomy volunteers consumed portions of test foods or pharmaceutical folate preparations (biological active (6S)-5-methyl-tetrahydrofolic acid) on individual test days in random order. Relative folate absorption was determined using kinetic parameters from post-dose plasma folate concentrations and urinary folate excretion. Non-absorbed folate from the dose was estimated by folate excreted with the stomal effluent. Each volunteer acted as its own control by inclusion of a test day without folate application and another with an i.m. injection of a pharmaceutical folate preparation to account for baseline data and e.g. bile folate excretion. Individual relative folate absorption from test foods was 49 and 41% for strawberries and broccoli, respectively. Depending on the matrix of tested foods, different length of gut passage times was observed. Initial results for one volunteer indicate that ca 80% folate from oral doses was “recovered” after 10–12 h post-dose, and this amount being independent of the size of the administered dose. This implies that the presented model provides a suitable standardized tool to compare folate availability from foods before and after food processing.