Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-27T14:32:04.776Z Has data issue: false hasContentIssue false
  • English
  • Français

Protein requirements and ageing: metabolic demand and efficiency of utilization*

Published online by Cambridge University Press:  09 March 2007

A. Fereday ,
N. R. Gibson ,
M. Cox ,
P. J. Pacy  and
D. J. Millward
A. Fereday
Affiliation:
Centre for Nutrition and Food Safety, School of Biological Sciences, University of Surrey, Guildford GU2 5XH
N. R. Gibson
Affiliation:
Centre for Nutrition and Food Safety, School of Biological Sciences, University of Surrey, Guildford GU2 5XH
M. Cox
Affiliation:
Centre for Nutrition and Food Safety, School of Biological Sciences, University of Surrey, Guildford GU2 5XH
P. J. Pacy
Affiliation:
Unit of Metabolic Medicine, St Mary's Hospital, Praed Street, London, W2 1PG
D. J. Millward
Affiliation:
Centre for Nutrition and Food Safety, School of Biological Sciences, University of Surrey, Guildford GU2 5XH
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.

The protein requirements of the elderly were investigated with [13C]leucine balance studies of metabolic demand, the efficiency of postprandial protein utilization (PPU) and the consequent apparent protein requirement. Ten elderly subjects aged 68–91 years (five men and five women) and ten young adult subjects aged 21–31 years (five men and five women) were infused with L-[1-13C]leucine for 9h commencing in the postabsorptive state (0–3h), continuing during the half-hourly feeding of low-protein meals (LP; protein 3% energy, 3–6 h), and during similar feeding of isoenergetic higher protein meals (HP; protein 15% energy, 6–9h). Leucine oxidation and balance were determined from plasma [l-13C]-α-ketoisocaproate enrichment and expired 13CO2 excretion measured during the 3rd hour of each 3h period. The protein intake during the HP phase was similar to the habitual intake estimated in the subjects from 24h urinary N excretion. Metabolic demand was defined as equal to twice the body-protein equivalent of measured postabsorptive leucine oxidation. The efficiency of PPU was calculated from the increased leucine oxidation observed during feeding, and the apparent protein requirement was defined as metabolic demand/PPU and calculated in relation to both body weight (BW) and fat-free mass (FFM) determined by densitometry or bioimpedance. Metabolic demand in the young adults was 0·83g protein/kg per d; in both elderly groups it was 36% lower when expressed per kg BW and 30% lower when expressed per kg FFM. The apparent protein requirement calculated from metabolic demand and PPU was 0·99g protein/kg per d in the young adults and this was also lower in the elderly, although this was only significant in the men (0·66g per kg BW, P=0·013; 0·79g per kg FFM, P=0·02). The results show that in this group of healthy elderly adults protein requirements as assessed from leucine balance studies were either similar to or less than those of younger adults.

Keywords

ElderlyProtein requirementsLeucine oxidation
Type
Human and Clinical Nutrition
Information
British Journal of Nutrition , Volume 77 , Issue 5 , May 1997 , pp. 685 - 702
Copyright
Copyright © The Nutrition Society 1997

References

REFERENCES

Abumrad, N. N., Rabin, D., Diamond, M. P. & Lacy, W. W. (1981). Use of a heated superficial hand vein as an alternative site for the measurement of amino acid concentration and for the study of glucose and alanine kinetics in man. Metabolism Clinical and Experimental 30, 936–940.CrossRefGoogle Scholar
Bier, D. M., Matthews, D. E. & Young, V. R. (1985). Interpretation of amino acid kinetic studies in the context of whole-body protein metabolism. In Substrate and Energy Metabolism in Man, pp. 27–36 [Garrow, J. S. and Halliday, D., editors]. London and Paris: John Libbey.Google Scholar
Calloway, D. H., Odell, A. C. F. & Margen, S. (1971). Sweat and miscellaneous N losses in human balance studies. Journal of Nutrition 101, 775–786.Google Scholar
Campbell, W. W., Crim, M. C., Dallal, G. E., Young, V. R. & Evans, W. J. (1994). Increased protein requirements in elderly people: new data and retrospective reassessments. American Journal of Clinical Nutrition 60, 501–509.CrossRefGoogle ScholarPubMed
Campbell, W. W. & Evans, W. J. (1996). Protein requirements of elderly people. European Journal of Clinical Nutrition 50, Suppl. 1, S180–S185.Google ScholarPubMed
Cohn, S. H., Vartsky, D., Yasumura, S., Sawitsky, A., Zanzi, I., Vaswani, A. & Ellis, K. J. (1980). Compartmental body composition based on total-body N, potassium and calcium. American Journal of Physiology 239, E524–E530.Google Scholar
Khoury, A. E. El, Fukagawa, N. K., Sanchez, M., Tsay, R. M., Gleason, R. E., Chapman, T. E. & Young, V. R. (1994). The 24hr pattern and rate of leucine oxidation with particular reference to tracer estimates of leucine requirements. American Journal of Clinical Nutrition 59, 1012–1020.CrossRefGoogle Scholar
Evans, W. J. & Campbell, W. W. (1993). Sarcopenia and age-related changes in body composition and functional capacity. Journal of Nutrition 123, 465–468.CrossRefGoogle ScholarPubMed
Fereday, A., Gibson, N. R., Cox, M., Halliday, D., Pacy, P. J. & Millward, D. J. (1994). Postprandial protein utilization in the elderly. Proceedings of the Nutrition Society 53, 202A.Google Scholar
Food and Agriculture Organization/World Health Organization (1991). Protein Quality Evaluation. FAO Food and Nutrition Paper no. 51. Rome: FAO.Google Scholar
Food and Agriculture Organization/World Health Organization/United Nations University (1985). Energy and Protein Requirements. Technical Report Series no. 724. Geneva: World Health Organization.Google Scholar
Forbes, G. B. & Reiner, J. C. (1970). Adult lean body mass declines with age: some longitudinal observations. Metabolism 19, 653–663.CrossRefGoogle ScholarPubMed
Gibson, N. R., Fereday, A., Cox, M., Halliday, D., Pacy, P. J. & Millward, D. J. (1996). Influences of dietary energy and protein on leucine kinetics during feeding in healthy adults. American Journal of Physiology 33, 282–291.Google Scholar
Jackson, A. A. (1993). Chronic malnutrition: protein metabolism. Proceedings of the Nutrition Society 52, 1–10.CrossRefGoogle ScholarPubMed
Jackson, A. A. (1995). Is leucine produced by the colonic microflora? American Journal of Clinical Nutrition 62, 977–978.Google Scholar
Millward, D. J., Jackson, A. A., Price, G. & Rivers, J. P. W. (1989). Human amino acid and protein requirements: current dilemmas and uncertainties. Nutrition Research Reviews 2, 109–132.CrossRefGoogle ScholarPubMed
Millward, D. J. & Pacy, P. J. (1995). Postprandial protein utilisation and protein quality assessment in man. Clinical Science 88, 597–606.CrossRefGoogle ScholarPubMed
Millward, D. J., Price, G., Pacy, P. J. H. & Halliday, D. (1991). Whole body protein and amino acid turnover in man: what can we measure with confidence? Proceedings of the Nutrition Society 50, 195–214.CrossRefGoogle ScholarPubMed
Millward, D. J. & Rivers, J. (1988). The nutritional role of indispensible amino acids and the metabolic basis for their requirements. European Journal of Clinical Nutrition 42, 367–393.Google ScholarPubMed
Millward, D. J. & Roberts, S. B. (1996). Protein requirements of older individuals. Nutrition Research Reviews 9, 67–87.CrossRefGoogle ScholarPubMed
Pacy, P. J., Price, G. M., Halliday, D., Quevedo, M. R. & Millward, D. J. (1994). N homeostasis in man: 2. The diurnal responses of protein synthesis, degradation and amino acid oxidation to diets with increasing protein intakes. Clinical Science 86, 103–118.CrossRefGoogle ScholarPubMed
Pacy, P., Quevedo, R. M., Gibson, N. R., Cox, M., Koutedakis, Y. & Millward, D. J. (1995). Body composition measurements in international heavyweight oarswomen: a comparison of five methods. The Journal of Sports Medicine and Physical Fitness 35, 67–74.Google Scholar
Price, G. M., Halliday, D., Pacy, P. J., Quevedo, M. R. & Millward, D. J. (1994). N homeostasis in man: influence of protein intake on the amplitude of diurnal cycling of body N. Clinical Science 86, 91–102.CrossRefGoogle Scholar
Quevedo, M. R., Price, G. M., Halliday, D., Pacy, P. J. & Millward, D. J. (1994). N homeostasis in man: 3. Diurnal changes in N excretion, leucine oxidation and whole body leucine kinetics during a reduction from a high to a moderate protein intake. Clinical Science 86, 185–193.CrossRefGoogle Scholar
Rand, W. M., Scrimshaw, N. S. & Young, V. R. (1981). Conventional long term N balance studies for protein quality evaluation in adults: rationale and limitations. In Protein Quality in Humans: Assessment and In Vitro Estimation, pp. 59–97 [Bodwell, C. E., Atkins, J. S. and Hopkins, D. T., editors]. Westport, CT: The AUI Publishing Co. Inc.Google Scholar
Reilly, J. J., Murray, L. A., Wilson, J. & Durnin, J. V. G. A. (1994). Measuring the body composition of elderly subjects: a comparison of methods. British Journal of Nutrition 72, 33–44.CrossRefGoogle ScholarPubMed
Siri, W. E. (1961). Body composition from fluid spaces and density; analysis of methods. In Techniques for Measuring Body Composition, pp. 223–244 [Brozek, J. and Henschel, A., editors]. Washington, DC: National Academy of Sciences.Google Scholar
Steen, G., Isaksson, B. & Svanborg, A. (1979). Body composition at 70 and 75 years of age: a longitudinal population study. Journal of Clinical Experimental Gerontology 1, 185–200.Google Scholar
Waterlow, J. C., Garlick, P. J. & Millward, D. J. (1978). Protein Turnover in Mammalian Tissues and in the Whole Body. Amsterdam: Elsevier/North-Holland Biomedical Press.Google Scholar
Wenham, D., Pacy, P., Price, G. M., Millward, D. J. & Halliday, D. (1991). Bicarbonate recovery during feeding and fasting. Proceedings of the Nutrition Society 50, 47A.Google Scholar
Yeboah, N., Ah-Sing, E., Badalloo, A., Forrester, T., Jackson, A. & Millward, D. J. (1996). Transfer of 15N from urea to the circulating lysine pool in the human infant. Proceedings of the Nutrition Society 55, 37A.Google Scholar
Zanni, E., Calloway, D. H. & Zezullca, A. Y. (1979). Protein requirements of elderly men. Journal of Nutrition 109, 513–524.CrossRefGoogle ScholarPubMed