Dietary fibre-rich resistant starches promote ammonia detoxification in the human colon as measured by lactose-[15N2]ureide

• Published in: Isotopes in environmental and health studies Vol. 51; no. 4; pp. 488 - 496
• Main Authors: Wutzke, Klaus D., Tisztl, Michael, Salewski, Birgit, Glass, Änne
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 02.10.2015
• Subjects: Adult; adults; ammonia; Ammonia - blood; Ammonia - metabolism; Ammonia - urine; amylose; blood; colon; Colon - metabolism; corn starch; Dietary Carbohydrates - administration & dosage; Dietary Carbohydrates - metabolism; dietary fiber; Dietary Fiber - administration & dosage; Dietary Fiber - metabolism; dietary fibre; Dietary Supplements - analysis; excretion; feces; Feces - chemistry; Female; Humans; isotope application in medicine; Lactose - analysis; Lactose - blood; Lactose - urine; lactose-; Male; mass spectrometry; men; nitrogen; Nitrogen - blood; Nitrogen - metabolism; Nitrogen - urine; Nitrogen Isotopes - analysis; Nitrogen Isotopes - blood; Nitrogen Isotopes - urine; nitrogen-15; peas; Pisum sativum - chemistry; potatoes; resistant starch; Solanum tuberosum - chemistry; stable isotope tracer techniques; stable isotopes; Urea - analogs & derivatives; Urea - analysis; Urea - blood; Urea - urine; ureide; urine; Young Adult; Zea mays - chemistry; colon metabolism; nitrogen-15; resistant starch; men; lactose-[15N2]ureide; stable isotope tracer techniques; dietary fibre; isotope application in medicine
• ISSN: 1477-2639; 1025-6016; 1477-2639
• DOI: 10.1080/10256016.2015.1092967

Three resistant starches (RSs), namely fibre of potatoes (FP), wrinkle pea starch (WPS), and high amylose maize starch (HAMS) with different dietary fibre contents, were supplemented in adults to evaluate their effects on urinary nitrogen and ammonia excretion as well as on faecal nitrogen excretion by means of lactose-[ ¹⁵N ₂]ureide (¹⁵N-LU) degradation. Twenty subjects received a regular diet either without or with the supplementation of FP, WPS, and HAMS in a randomized order. After administration of ¹⁵N-LU, urine and faeces were collected over 48 and 72 h, respectively, whereas blood was collected after 6 h. The ¹⁵N-abundances were measured by isotope ratio mass spectrometry. In comparison to the dry run, supplementation with RS significantly lowered renal ¹⁵N-excretion (dry run: 43.2 %, FP: 34.6 %, WPS: 37.9 %, HAMS: 36.4 %) as well as the corresponding ¹⁵NH ₃-excretion (dry run: 0.08 %, FP: 0.06 %, HAMS: 0.05 %), clearly indicating a reduced colonic nitrogen generation at high dietary fibre intake.