 |
Prof. Vernon R. Young, 1997 Awardee
Vernon Young (deceased) was born in Rhyl (Wales) in 1937. After graduating from the University of Reading (England), he moved to the United States where he obtained a Ph.D. in Nutrition from the University of California, Davis, in 1965. He then became Assistant Professor, Associate Professor and then, in 1977, Professor at M.I.T. in Boston. He was President of the American Institute of Nutrition in 1991 / 1992. He was also Director of the Mass Spectrometry Facility at Shriners Burns Institute in Boston.
Research Work
Vernon Young was best known for his contributions to the study of protein and amino acid metabolism, how it changes through the human life cycle, and in response to nutritional deficiencies and injuries such as burns. A series of investigations with Nevin Scrimshaw and other collaborators on nitrogen losses in individuals of various ages showed that dietary protein was less effective in balancing such losses than had been previously believed. This led them to question the existing concept of the biological value of dietary proteins and also to re-examine the existing recommendations made by the FAO and WHO for protein intakes in healthy subjects. In individuals aged between 56 and 80, recommended values were found to be at least 25% too low. In the case of children with burns, the group showed an enhanced rate of protein synthesis and breakdown implying a protein requirement far greater than the recommended amount for healthy individuals. Turning to individual amino acids, Prof. Young’s group showed that plasma levels responded to changes in dietary supply. Studies on tryptophan, threonine, valine and lysine showed that plasma responses are sensitive indicators of the point at which amino acid concentrations become marginal or even inadequate to sustain normal rates of protein turnover. Analysing published studies of such obligatory nitrogen losses and of whole body turnover convinced Prof. Young’s group that existing recommendations for amino acid requirements were too low. His own studies of 13C-labelled amino acid turnover confirmed this view. They calculated that the minimum requirement for indispensable amino acids for adults was 2-3 times higher than current FAO/WHO recommendations.
Vernon Young also developed novel biochemical techniques and non-invasive methods for the study of protein turnover in skeletal muscle. Much of his group’s pioneering work was on the use of stable isotope probes such as 15N, 2H, 18O and 13C for the study of nitrogen metabolism in premature infants and in children with burns as well as for determining quantitative amino-acid needs in older individuals. Prof. Young’s group also developed a method for assessing muscle protein turnover by measuring the daily urinary output of 3-methylhistidine. This remains the only non-invasive method for the assessment of muscle protein degradation in man. Prof. Young’s research also extended to the study of the metabolism of iron, zinc, copper and selenium in man. In collaboration with M. Janghorbani, the group developed methods for measuring the stable isotopes of these metals in blood, urine and faeces. They found that separate mechanisms exist for the absorption of zinc and copper and that the absorption rate increases following dietary restriction. Extending the technique to selenium gave a valuable measure of the turnover of this element. In addition, a major interest of Pr. Young’s research team was the question of protein quality. Their research concluded, amongst other things, that soybean proteins could serve as the sole source of nitrogen and essential amino acids. This work did much to encourage the adoption of a method of assessing the nutritional value of food proteins based on estimates of amino acid requirements in the United States. By attributing the Danone International Prize for Nutrition to Vernon Young, the Jury wished to acknowledge the fundamental and diversified contribution he made to progress in nutrition science and human health. Selected Bibliography
1. Janghorbani M. and Young VR. Stable isotopes of dietary mineral bioavailability in humans, with special reference to zinc. In: Clinical Biochemical and Nutritional Aspects of Trace Elements, 1982. Alan R Liss, New York, pp. 447-468
2. Rand WM, Scrimshaw NS and Young VR. A retrospective analysis of long-term metabolic balance studies: Implications for understanding dietary nitrogen and energy utilization. American Journal of Clinical Nutrition 1985; 41: 1339-1350 3. Young VR. and Bier DM. A kinetic approach to the determination of human acid requirements. Nutrition Reviews 1987; 45: 289-298 4. Young VR. Protein and amino acid metabolism with reference to aging and the elderly. 1989. Alan R Liss Inc., New York 5.Young VR,. Yu YM and Krempf M. Protein and amino acid turnover using the stable isotopes 15N, 13C and 2H as probes. In: New Techniques in Nutritional Research. Eds. RG Whitehead and A Prentice. 1990. Academic Press, San Diego, pp. 17-72 6. Young VR,. Pellet PL. Protein evaluation, amino acid scoring and food and drug administration’s proposed food labelling regulations. Issues and opinions in nutrition. Journal of Nutrition 1991; 121: 145-150 7. Young VR,. Munro HM. Index of muscle protein degradation. Citation Classic®, Current Contents. 1992, Sept. 32 (#38), p. 9 8. Young VR. Adult amino acid requirements: The case for a major revision in current recommendations. Journal of Nutrition 1994; 124: 1517S-1523S 9. Roberts S, Fuss P, Heyman M, Young VR. Influence of age on energy requirements. American Journal of Clinical Nutrition 1995; 62 (Suppl): 1053S-1058S |
