Dietary fibre-rich resistant starches promote ammonia detoxification in the human colon as measured by lactose-[¹⁵N₂]ureide.
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-[(15)N2]ureide ((15)N-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 (15)N-LU, urine and faeces were collected over 48 and 72 h, respectively, whereas blood was collected after 6 h. The (15)N-abundances were measured by isotope ratio mass spectrometry. In comparison to the dry run, supplementation with RS significantly lowered renal (15)N-excretion (dry run: 43.2%, FP: 34.6%, WPS: 37.9%, HAMS: 36.4%) as well as the corresponding (15)NH3-excretion (dry run: 0.08%, FP: 0.06%, HAMS: 0.05%), clearly indicating a reduced colonic nitrogen generation at high dietary fibre intake.
a Research Laboratory, Children's Hospital , University of Rostock , Rostock , Germany.
Klaus D
KD
Wutzke
a Research Laboratory, Children's Hospital , University of Rostock , Rostock , Germany.
Michael
M
Tisztl
a Research Laboratory, Children's Hospital , University of Rostock , Rostock , Germany.
Birgit
B
Salewski
b Institute for Biostatistics and Informatics in Medicine and Ageing Research, University of Rostock , Rostock , Germany.
Änne
Ä
Glass
D000328:Adult; D000641:Ammonia / Q000097:blood / Q000378:metabolism* / Q000652:urine; D003106:Colon / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004043:Dietary Fiber / Q000008:administration & dosage / Q000378:metabolism; D019587:Dietary Supplements / Q000032:analysis; D005243:Feces / Q000737:chemistry; D005260:Female; D006801:Humans; D007785:Lactose / Q000032:analysis / Q000097:blood / Q000652:urine; D008297:Male; D009584:Nitrogen / Q000097:blood / Q000378:metabolism / Q000652:urine; D009587:Nitrogen Isotopes / Q000032:analysis / Q000097:blood / Q000652:urine; D018532:Pisum sativum / Q000737:chemistry*; D011198:Solanum tuberosum / Q000737:chemistry*; D014508:Urea / Q000031:analogs & derivatives / Q000032:analysis / Q000097:blood / Q000652:urine; D055815:Young Adult; D003313:Zea mays / Q000737:chemistry*
D004040:Dietary Carbohydrates; D004043:Dietary Fiber; D009587:Nitrogen Isotopes; C121442:lactose ureide; D000641:Ammonia; D014508:Urea; D007785:Lactose; D009584:Nitrogen
colon metabolism; dietary fibre; isotope application in medicine; lactose-[15N2]ureide; men; nitrogen-15; resistant starch; stable isotope tracer techniques