Turner Justine M, Humayun Mohammad A, Elango Rajavel, Rafii Mahroukh, Langos Veronika, Ball Ronald O, Pencharz Paul B
Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.
Am J Clin Nutr. 2006 Mar;83(3):619-23. doi: 10.1093/ajcn.83.3.619.
Current total sulfur amino acid (TSAA) requirements of children are based on a factorial estimate that involves several assumptions.
The objective was to determine the TSAA requirement (methionine alone) of healthy school-age children by measuring the appearance of 13CO2 (F13CO2) in breath after the oxidation of l-[1-13C]phenylalanine in response to graded methionine intakes.
Six healthy school-age children randomly received each of 6 methionine intakes (0, 5, 10, 15, 25, and 35 mg.kg(-1).d(-1)) along with an amino acid mixture to give a final protein intake of 1.5 g.kg(-1).d(-1) and an energy intake of 1.7 x resting energy expenditure. The diet was devoid of cysteine. The mean TSAA requirement was determined by applying a biphase linear regression crossover analysis on F13CO2 data, which identified a breakpoint at minimal F13CO2 in response to graded methionine intakes.
The mean and population-safe (upper 95% CI) intakes of TSAA (as methionine) were determined to be 12.9 and 17.2 mg.kg(-1).d(-1), respectively.
The current study suggests that children of this age group have a mean TSAA requirement similar to that of adults (12.6 mg.kg(-1).d(-1)). Therefore, it is valid to use a factorial approach, which assumes that maintenance requirements in childhood are similar to adult requirements, to estimate TSAA requirements in school-age children.
目前儿童总硫氨基酸（TSAA）的需求量是基于一种涉及多个假设的析因估计得出的。
通过测量在不同蛋氨酸摄入量下，l-[1-13C]苯丙氨酸氧化后呼出气体中13CO2（F13CO2）的出现情况，来确定健康学龄儿童的TSAA需求量（仅蛋氨酸）。
六名健康学龄儿童随机接受六种蛋氨酸摄入量（0、5、10、15、25和35mg·kg⁻¹·d⁻¹）中的每一种，同时摄入氨基酸混合物，以使最终蛋白质摄入量达到1.5g·kg⁻¹·d⁻¹，能量摄入量达到静息能量消耗的1.7倍。饮食中不含半胱氨酸。通过对F13CO2数据应用双相线性回归交叉分析来确定平均TSAA需求量，该分析确定了在不同蛋氨酸摄入量下F13CO2最低时的一个断点。
TSAA（以蛋氨酸计）的平均摄入量和人群安全摄入量（95%置信区间上限）分别确定为12.9和17.2mg·kg⁻¹·d⁻¹。
当前研究表明，该年龄组儿童的平均TSAA需求量与成年人相似（12.6mg·kg⁻¹·d⁻¹）。因此，采用析因法来估计学龄儿童的TSAA需求量是有效的，该方法假定儿童的维持需求量与成年人相似。
