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Evidence that protein requirements in healthy school‐age children are significantly underestimated in current recommendations
Author(s) -
Elango Rajavel,
Humayun Mohammad A,
Ball Ronald O,
Pencharz Paul B
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.227.8
Subject(s) - phenylalanine , tyrosine , energy requirement , population , zoology , crossover study , amino acid , chemistry , protein requirement , medicine , biology , biochemistry , mathematics , regression , statistics , body weight , environmental health , alternative medicine , pathology , placebo
Protein (PRO) requirements in healthy school‐age children were determined by the indicator amino acid oxidation (IAAO) method. Seven, healthy children (6 ‐ 11 y) each randomly received a minimum of 6 graded PRO intakes (range= 0.1 ‐ 2.56 g/kg/d) to a total of 47 studies. The diets provided energy at 1.7 X REE and were made isocaloric using carbohydrates. PRO was given as an amino acid mixture based on egg protein pattern, except phenylalanine and tyrosine intakes, which were maintained constant across intakes. Oxidation of L‐[1‐ 13 C]‐phenylalanine to 13 CO 2 ( F 13 CO 2 ) was measured in breath samples at baseline and isotopic steady state. Linear regression crossover analysis identified a breakpoint (requirement) at minimal F 13 CO 2 in response to different PRO intakes. Figure 1. Phenylalanine oxidation ( F 13 CO 2 , µmol/kg/hr) in response to graded protein intakes The mean and population‐safe PRO requirements were determined to be 1.35 and 1.6 g/kg/d, respectively (Figure 1). These results are significantly higher than the mean and population‐safe PRO requirements of 0.76 and 0.95 g/kg/d, respectively, currently recommended by the Dietary Reference Intakes (DRI 2005) for macronutrients. This study is the first to directly estimate protein requirements in children using stable isotopes and indicates that the current recommendations are severely underestimated. (CIHR supported)