Methionine requirements in healthy adolescents.

To investigate methionine requirements in healthy adolescents, we conducted an experiment in 28 children age 15.6+2.1 years, wt. 57.8+9.7 kg, using the intravenous indicator amino acid oxidation and balance (IV‐IAAOB) technique. Children were randomly assigned to 7 different levels of methionine intake and received an L‐amino acid diet providing the test methionine and adequate protein and energy intake for 3days. On day 3, they received a primed, continuous, 3 hour fast, 5 hour fed intravenous infusion of L‐[1‐ 13 C] leucine. Blood samples were obtained for isotopic enrichment of [ 13 C] KIC and 13 CO 2 . Preliminary data for 18 patients is presented. There was no difference in leucine balance at methionine intakes of 7, 14 or 21 mg. Leucine balance at methionine intakes of 7 and 14 mg were lower (P<0.01) when compared to intakes of 25, 29, 36 and 43mg. There was a trend toward a difference (P<0.06) on leucine balance at methionine intakes of 21 and 25mg. Leucine oxidation was lower (P<0.01) at methionine intakes of 25, 29, 36 and 43 mg.kg −1 .d −1 than at 7 and 14 mg.kg −1 .d −1 . In this preliminary data, there was a trend to achieve leucine balance at methionine intakes of 25 mg.kg −1 .d −1 . Ajinomoto 3ARP Program. NIH DK62363.