Fructose_ Evaluation by Breath Testing.pdf

The Ability of the Normal Human Small Intestine to Absorb Fructose: Evaluation by Breath Testing Satish S.C Rao*, Ashok Attaluri, Leslie Anderson, and Phyllis Stumbo Department of Internal Medicine and Clinical Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA Abstract Background—Fructose consumption is rising and its malabsorption causes common gastrointestinal symptoms. Because its absorption capacity is poorly understood, there is no standard method of assessing fructose absorption. We performed a dose response study of fructose absorption in healthy subjects in order to develop a breath test to distinguish normal from abnormal fructose absorption capacity. Methods—In a double-blind study, 20 healthy subjects received 10% solutions of 15g, 25g and 50g of fructose and 33 % solution of 50g fructose on 4 separate days, at weekly intervals. Breath samples were assessed for hydrogen and methane over five hours, and symptoms were recorded. Results—No subject tested positive with 15g. Two (10%) tested positive with 25g fructose but were asymptomatic. Sixteen (80 %) tested positive with 50g (10% solution) and 11 (55%) had symptoms. Breath H2 was elevated in 13 (65%), CH4 in 1 (5%) and both in 2 (10%). Twelve (60%) tested positive with 50g (33% solution) and 9 (45%) experienced symptoms. The area under the curve for H2 and CH4 was higher (p 0.01) with 50g compared to lower doses. There were no gender differences. Conclusions—Healthy subjects have the capacity to absorb up to 25g fructose whereas many exhibit malabsorption and intolerance with 50g fructose. Hence, we recommend 25g as the dose for testing subjects with suspected fructose malabsorption. Breath samples measured for H2 and CH4 concentration at 30 minute intervals and for 3 hours will detect most subjects with fructose malabsorption. Keywords fructose; malabsorption; breath test; intolerance; hydrogen; methane Introduction During the last decade, sucrose consumption has increa