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Research article - Peer-reviewed, 2003

A human model to determine folate bioavailability from food: a pilot study for evaluation

Witthoft CM, Stralsjo L, Berglund G, Lundin E

Abstract

Background: Knowledge about folate bioavailability from food is essential for the estimation of dietary requirements. Yet, there is a lack of data obtained from validated human studies performed with physiological folate doses. Objective: In this pilot study, a new model for the determination of folate is developed and validated. Design: Two healthy ileostomy volunteers consumed under strictly standardised procedures single portions of test foods or an oral dose of a pharmaceutical folate preparation of the natural folate diastereomer (6S)-5-methyltetrahydrofolate. Relative folate absorption from oral doses versus an i-m. injection of the same pharmaceutical preparation was determined using post-dose plasma folate concentration curves. Non-absorbed folate was estimated by post-dose folate excretion into stomal effluent. Results: Estimated by plasma area under the curve, relative folate absorption ranged from 47-67% for oral doses from the test foods strawberries and broccoli and the pharmaceutical (6S)-5-methyltetrahydrofolate preparation. 19-44% of the dietary folate was excreted with the stomal effluent during 10 h post-dose. Varying gut passage times were observed for different food matrices by determining ileostomal folate excretion in 2 h intervals. Around 90% of the folate from the oral doses was "recovered" in the collected body fluids plasma and stomal effluent already 10 h post-dose, independent of the size of the administered folate dose of 200 or 400 mikogram (0.4 or 0.9 mikromol). Conclusion: This implies that the presented model provides a suitable tool to estimate folate bioavailability from foods

Keywords

folate absorption; plasma folate kinetics; urinary folate excretion; folate in ileostomal affluent; ileostomists

Published in

Scandinavian Journal of Nutrition
2003, Volume: 47, number: 1, pages: 6-18
Publisher: Swedish Nutrition Foundation