Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-13T05:51:50.322Z Has data issue: false hasContentIssue false
  • English
  • Français

The effect of rate and extent of weight loss on urea salvage in obese male subjects

Published online by Cambridge University Press:  07 June 2007

Peter Faber ,
Alexandra M. Johnstone ,
Eileen R. Gibney ,
Marinos Elia ,
R. James Stubbs ,
Paula L. Roger ,
Eric Milne ,
William Buchan  and
Gerald E. Lobley
Peter Faber*
Affiliation:
Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK University of Southern Denmark, Odense University, Campusvej 55, DK-5000 Odense C, Denmark
Alexandra M. Johnstone
Affiliation:
Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
Eileen R. Gibney
Affiliation:
Institute of Human Nutrition, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, England, UK
Marinos Elia
Affiliation:
Institute of Human Nutrition, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, England, UK
R. James Stubbs
Affiliation:
Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
Paula L. Roger
Affiliation:
Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
Eric Milne
Affiliation:
Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
William Buchan
Affiliation:
Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
Gerald E. Lobley
Affiliation:
Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
*
*Corresponding author: Dr Peter Faber, fax +44 1224 716629, email faber@doctors.org.uk
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

It is well established that in human subjects a proportion of urea production undergoes hydrolysis in the gastrointestinal tract with release of N potentially available for amino acid synthesis. Previous studies have suggested adaptive changes in urea kinetics, with more urea-N retained within the metabolic pool during reduced dietary intakes of energy and protein. We therefore investigated the effect of rate and extent of weight loss on adaptive changes in urea kinetics in two groups (each n 6) of obese men (mean age 43 (sd 12) years, BMI 34·8 (sd 2·9)kg/m2) during either total starvation for 6d or a very-low-energy diet (2·55MJ/d) for 21d. Subjects were resident in the Human Nutrition Unit of the Rowett Research Institute (Aberdeen, Scotland, UK) and lost 6 and 9% initial body weight within the starvation and dieting groups respectively. Changes in urea-N metabolism were assessed by stable isotope tracer kinetics using [15N15N]urea infused intravenously for 36h before, during and after weight loss. In response to weight loss, urea production decreased (P<0·01) by 25% from 278 to 206μmol urea-N/h per kg within the dieting group only. However, no changes were observed in the proportion of urea being hydrolysed in the gastrointestinal tract (range 20–25%) or in the proportion of N retained for anabolic purposes (80–85% urea-N from gastrointestinal hydrolysis) within either group. It was concluded that no adaptive changes in urea kinetics occurred in response to either the different rate or extent of weight loss.

Keywords

Urea kineticsWeight lossObesity
Type
Research Article
Information
British Journal of Nutrition , Volume 90 , Issue 1 , July 2003 , pp. 221 - 231
Copyright
Copyright © The Nutrition Society 2003

References

Cahill, GF (1970) Starvation in man. New Eng J Med 19, 668–675.Google Scholar
Calloway, D, Odell, A & Margen, S (1971) Sweat and miscellaneous nitrogen losses in human balance studies. J Nutr 101, 775–786.Google ScholarPubMed
Child, S, Soares, M, Reid, M, Persaud, C, Forrester, T & Jackson, AA (1997) Urea kinetics varies in Jamaican women and men in relation to adiposity, lean body mass and protein intake. Eur J Clin Nutr 57, 107–115.CrossRefGoogle Scholar
Crocker, CL (1967) Rapid determination of urea nitrogen in serum or plasma without deproteinization. Am J Med Technol 33, 361–365.Google ScholarPubMed
Davidson, J, Mathieson, J & Boyne, AW (1970) The use of automation in determining nitrogen by the Kjeldahl method, with calculations by computer. Analyst 95, 181–193.CrossRefGoogle ScholarPubMed
Department of Health and Social Security (1987) The Use of Very-Low-Calorie Diets in Obesity. London: H. M. Stationery Office.Google Scholar
Dulloo, AG, Jacquet, J & Girardier, L (1997) Poststarvation hyperphagia and body fat overshooting in humans: a role for feedback signals from lean and fat tissues. Am J Clin Nutr 65, 717–723.CrossRefGoogle ScholarPubMed
Elia, M (1991) Effect of starvation and very low calorie diets on protein–energy interrelationships in lean and obese subjects. In Protein–Energy Interactions, pp. 249–284 [Scrimshaw, N and Schurch, B, editors]. Lausanne: Nestle Foundation.Google Scholar
Elia, M & Livesey, G (1992) Energy expenditure and fuel selection in biological systems: The theory and practice of calculations based on indirect calorimetry and tracer methods. In Metabolic Control of Eating, Energy Expenditure and the Bioenergetics of Obesity, pp. 68–131. [Simopoulus, A, editor]. Base: Karger.Google Scholar
Elia, M, Stubbs, RJ & Henry, CJ (1999) Differences in fat, carbohydrate, and protein metabolism between lean and obese subjects undergoing total starvation. Obes Res 7, 597–604.CrossRefGoogle ScholarPubMed
El-Khoury, A, Ajami, A, Fukagawa, N, Chapman, T & Young, VR (1996) Diurnal pattern of the interrelationships among leucine oxidation, urea production and hydrolysis in humans. Am J Physiol 271, E563–E573.Google ScholarPubMed
El-Khoury, A, Fukagawa, N, Sanchez, M, et al. (1994) Validation of the tracer-balance concept with reference to leucine: 24-h intravenous tracer studies with l-[1−13C]leucine and [15N15N]urea. Am J Clin Nutr 59, 1000–1011.CrossRefGoogle Scholar
Forslund, AE, Hambraeus, L, Olsson, RM, El-Khoury, AE, Yu, YM & Young, VR (1998) The 24-h whole body leucine and urea kinetics at normal and high protein intakes with exercise in healthy adults. Am J Physiol 275, E310–E320.Google ScholarPubMed
Fuller, NJ, Jebb, SA, Laskey, MA, Coward, WA & Elia, M (1992) Four-compartment model for the assessment of body composition in humans: comparison with alternative methods and evaluation of the density and hydration of fat-free mass. Clin Sci 82, 687–693.CrossRefGoogle Scholar
Furst, P, Jonsson, A, Josephson, B & Vinnars, E (1970) Distribution in muscle and liver vein protein of 15N administered as ammonium acetate to man. J Appl Physiol 29, 307–312.CrossRefGoogle ScholarPubMed
Gibson, N, Ah-Singh, E, Badalloo, A, Forrester, T, Jackson, AA & Millward, D (1997) Transfer of 15N from urea to the circulating dispensable and indispensable amino acid pool in the human infant. Proc Nutr Soc 56, 79 Abstr.Google Scholar
Goldberg, G, Black, A, Jebb, S et al. (1991) Critical evaluation of energy intake data using fundamental principles of energy physiology: 1. Derivation of cut-off limits to identify under recording. Eur J Clin Nutr 45, 569–581.Google ScholarPubMed
Jackson, AA (1991) Critique of protein–energy interactions in vivo: Urea kinetics. In Protein-Energy Interactions, pp 63–79. [Scrimshaw, N and Schurch, B, editors]. Lausanne: Nestle Foundation.Google Scholar
Jackson, AA (1994 a) Urea as a nutrient: Bioavailability and role in nitrogen economy. Arch Dis Child 70, 3–4.CrossRefGoogle ScholarPubMed
Jackson, AA (1994 b) Is leucine produced by the colonic microflora? (Commentary). Am J Clin Nutr 60, 977–979.CrossRefGoogle Scholar
Jackson, AA (1998) Salvage of urea-nitrogen in the large bowel: Functional significance in metabolic control and adaptation. Biochem Soc Trans 26, 231–236.CrossRefGoogle ScholarPubMed
Jackson, AA (1999) Limits of adaptation to high dietary protein intakes. Eur J Clin Nutr 53, S44–S52.CrossRefGoogle ScholarPubMed
Jackson, AA, Danielsen, M & Boyes, S (1993) A noninvasive method for measuring urea kinetics with a single dose of [15N15N]urea in free-living humans. J Nutr 123, 2129–2136.Google ScholarPubMed
Jackson, AA, Landman, J & Picou, D (1981) Urea production rates in man in relation to the dietary intake of nitrogen and the metabolic state of the individual. In Nitrogen Metabolism in Man, pp. 249–251. [Waterlow, JC and Stephen, ML, editors]. London: Applied Science Publishers.Google Scholar
Jackson, AA, Picou, D & Landman, J (1984) The non-invasive measurement of urea kinetics in normal man by a constant infusion of [15N15N]urea. Hum Nutr Clin Nutr 38, 339–354.Google Scholar
Jahoor, F, Jackson, AA & Golden, MHN (1988) In vivo metabolism of nitrogen precursors for urea synthesis in the postprandial rat. Ann Nut Metabol 32, 240–244.CrossRefGoogle ScholarPubMed
Johnstone, AM, Stubbs, RJ & Harbron, C (1996) Effect of overfeeding macronutrients on day-to-day food intake in man. Eur J Clin Nutr 50, 418–430.Google ScholarPubMed
Langran, M, Moran, B, Murphy, J & Jackson, AA (1992) Adaptation to a diet low in protein: Effect of complex carbohydrate upon urea kinetics in normal men. Clin Sci 82, 191–198.CrossRefGoogle Scholar
Lobley, GE, Bremner, DM & Zuur, G (2000) Effects of diet quality on urea fates in sheep as assessed by refined, non-invasive [15N15N]urea kinetics. Br J Nutr 84, 459–468.CrossRefGoogle ScholarPubMed
Long, C, Jeevanandam, M & Kinney, J (1978) Metabolism and recycling of urea in man. Am J Clin Nutr 31, 1367–1382.CrossRefGoogle ScholarPubMed
Marsh, WH, Fingerhut, B & Miller, H (1965) Automated and manual direct methods for the determination of blood urea. Clin Chem 11, 624–627.CrossRefGoogle ScholarPubMed
Meakins, T & Jackson, AA (1996) Salvage of exogenous nitrogen enhances nitrogen balance in normal men consuming marginally inadequate protein diets. Clin Sci 90, 215–225.CrossRefGoogle ScholarPubMed
Metges, CC, Petzke, KJ & El-Khoury, AE (1999) Incorporation of urea and ammonia nitrogen into ileal and faecal microbial proteins and plasma free amino acids in normal men and ileostomates. Am J Clin Nutr 70, 1046–1058.CrossRefGoogle ScholarPubMed
Millward, DJ, Forrester, T & Ah-Singh, E (2000) The transfer of 15N from urea to lysine in the human infant. Br J Nutr 83, 505–512.CrossRefGoogle ScholarPubMed
Mitch, WE, Lietman, PS & Walser, M (1977) Effects of oral neomycin and kanamycin in chronic uremic patients. I. Urea metabolism. Kidney Internat 11, 116–122.CrossRefGoogle ScholarPubMed
Owen, O, Smalley, K, D'Alessio, D, Mozzoli, M & Dawson, E (1998) Protein fat and carbohydrate requirements during starvation: Anaplerosis and cataplerosis. Am J Clin Nutr 68, 12–34.CrossRefGoogle ScholarPubMed
Pullicino, E, Coward, WA, Stubbs, RJ & Elia, M (1990) Bedside and field methods for assessing body composition: comparison with the deuterium dilution technique. Eur J Clin Invest 40, 753–762.Google Scholar
Sands, JM (2002) Molecular approaches to urea transporters. J Am Soc Nephrol 13, 2795–2806.CrossRefGoogle ScholarPubMed
Sarraseca, A, Milne, E, Metcalf, M & Lobley, GE (1998) Urea recycling in sheep: Effects of intake. Br J Nutr 79, 79–88.CrossRefGoogle ScholarPubMed
Scrimshaw, N, Hussein, M, Murray, E, Rand, W & Young, VR (1972) Protein requirements of man: Variations in obligatory urinary and fecal nitrogen losses in young men. J Nutr 102, 1595–1604.CrossRefGoogle ScholarPubMed
Torrallardona, D, Harris, C, Coates, M & Fuller, M (1996) Microbial amino acid synthesis and utilization in rats: incorporation of 15N from 15NH4Cl into lysine in the tissues of germ free and conventional rats. Br J Nutr 76, 689–700.CrossRefGoogle ScholarPubMed
Torrallardona, D, Harris, C, Milne, E & Fuller, M (1994) The contribution of intestinal microflora to amino acid requirements in pigs. In Proceedings from 6th International Symposium on Digestive Physiology in Pigs, pp. 245–248. [Souffiant, WB and Hagemeister, H, editors]. Wageningen: Dummerstoif Forsch Inst Biol Landwirtsch Nutztiere.Google Scholar
Van Gaal, LF (1998) Dietary treatment of obesity. In Handbook of Obesity, pp. 875–890. [Bray, GA, Bouchard, C and James, WPT, editors]. New York: Marcel Dekker.Google Scholar
Varcoe, R, Halliday, D, Carson, E, Richards, P & Tavill, A (1975) Efficiency of utilization of urea nitrogen for albumin synthesis by chronically uremic and normal man. Clin Sci Mol Med 48, 379–390.Google ScholarPubMed
Watson, P, Watson, I & Batt, R (1980) Total body water volumes for adult males and females estimated from simple anthropometric measurements. Am J Clin Nutr 33, 27–39.CrossRefGoogle ScholarPubMed
Weijs, PJM, Calder, AG, Milne, E & Lobley, GE (1996) Conversion of [15N] ammonia into urea and amino acids in humans and the effect of nutritional status. Br J Nutr 76, 491–499.CrossRefGoogle ScholarPubMed
World Health Organization (1985) Principles for estimating protein requirements. In Energy and Protein Requirements. Report of a Joint FAO/WHO/UNU Expert Consultation, Technical Report Series no. 724, pp. 52–70. Geneva: WHO.Google Scholar
Yaboah, N, Ah-Singh, E, Badalloo, A, Forrester, T, Jackson, AA & Millward, D (1996) Transfer of 15N from urea to the circulating lysine pool in the human infant. Proc Nutr Soc 55, 37 Abstr.Google Scholar
Young, VR & El-Khoury, AE (1994) Reply to A. A. Jackson (Commentary). Am J Clin Nutr 60, 978–979.CrossRefGoogle Scholar
Young, VR, El-Khoury, AE, Raguso, CA, Forslund, AH & Hambraeus, L (2000) Rates of urea production and hydrolysis and leucine oxidation change linearly over widely varying protein intakes in healthy adults. J Nutr 130, 761–766.CrossRefGoogle ScholarPubMed
Young, VR, Yu, Y & Fukagawa, N (1992) Whole body energy and nitrogen (protein) relationships. In Energy Metabolism: Tissue determinants and Cellular Corollaries, pp. 139–161. [Kinney, JM and Tucker, HN, editors]. New York: Raven Press.Google Scholar