American Journal of Clinical Nutrition, Vol 50, 1475-1475, Copyright © 1989 by The American Society for Nutrition

Erratum

¹ AFRC Institute of Food Research, Colney Lane, Norwich, Norfolk NR4 7UA, UK
² MRC Dunn Clinical Nutrition Centre, 100 Tennis Court Road, Cambridge, CB2 1QE, UK

Dear Editor in Chief: Since our article entitled Estimation of energy expenditure, net carbohydrate utilization, and net fat oxidation and synthesis by indirect calorimetry: evaluation of errors with special reference to the detailed composition of fuels was published in Am J Clin Nutr 1988;47: 608-28, we became aware of an issue of possible confusion, which we would like to rectify. This concerns the metabolizable energy density of individual amino acids given in Table 3 under the column headed ME kJ/g (kcal/g). The quoted values have units of kJ(kcal)/g protein equivalent and not kJ(kcal)/g free amino acid, as is implied in the paper. The difference is of course the water of condensation, 1 mol H₂O per peptide bond, which for a protein is negligibly different from 18 g/mol amino acid. We should also like to draw attention to, and correctly record the values of H^eq, RQ, and O₂:N_u for tryptophan in Table 3. These should have been 19.403 kJ/LO₂ (4.637 kcal/LO₂) and 0.87 and 9.20 LO₂/gN_u, respectively. This notes an original error on our part. However, this has resulted in an error of only 0.1% to 0.2% in all corresponding estimated values for the conventional and artificial amino acid mixtures; this because of the relatively small contribution from this amino acid to total amino acids.