采用指示剂氨基酸氧化法测定健康年轻成年男性的苏氨酸需求量时，适应期的长短并无影响。
Length of Adaptation Has No Effect on the Threonine Requirement Determined in Healthy Young Adult Males Using the Indicator Amino Acid Oxidation Method.
机构信息
Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.
Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Departments of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada.
出版信息
J Nutr. 2023 Jul;153(7):2016-2026. doi: 10.1016/j.tjnut.2023.03.033. Epub 2023 Mar 31.
BACKGROUND
The indicator amino acid oxidation (IAAO) method is minimally invasive; therefore, it is applicable to study the amino acid (AA) requirements of individuals in various age groups. However, the accuracy of this method has been criticized because of the 8 h (1 d) protocol, which has been suggested to be too short an adaptation time for estimating AA requirements.
OBJECTIVES
The IAAO method was used to determine whether 3 or 7 d of adaptation to each threonine intake alters the threonine requirement in adult men compared to 1 d of adaptation.
METHODS
Eleven healthy adult men (19-35 y, body mass index (BMI) 23.4 in kg⋅m) were studied at 6 threonine intakes; each intake was studied over a 9 d period. Following 2 d of pre-adaptation to adequate protein intake (1.0 g·kg⋅d), subjects received experimental diets containing the randomly assigned test threonine intake (5, 10, 15, 20, 25, or 35 mg·kg·d) for 7 d. IAAO studies were performed on days 1, 3, and 7 of adaptation to the experimental diet. The rate of release of CO from the oxidation of L-[1-C]phenylalanine (FCO) was measured, and the threonine requirement was determined by applying mixed-effect change-point regression to the FCO data in R version 4.0.5. The 95% confidence interval (CI) was calculated using parametric bootstrap, and the requirement estimates on days 1, 3, and 7 were compared using analysis of variance (ANOVA).
RESULTS
The mean threonine requirements (upper, lower 95% CI) for days 1, 3, and 7 were 10.5 (5.7, 15.9), 10.6 (7.5, 13.7), and 12.1 (9.2, 15.0 mg·kg·d), respectively; and these requirements were not statistically different (P = 0.213).
CONCLUSIONS
We demonstrated that the short, 8 h IAAO protocol results in a threonine requirement that is not statistically different from that obtained on days 3 or 7 of adaptation in healthy adult males. This trial was registered at www.
CLINICALTRIALS
gov as NCT04585087.
背景
指示剂氨基酸氧化（IAAO）法具有微创性；因此，它适用于研究不同年龄组个体的氨基酸（AA）需求。然而，由于 8 小时（1 天）方案，该方法的准确性受到了批评，因为该方案对于估计 AA 需求来说，适应时间太短。
目的
本研究使用 IAAO 法来确定 3 或 7 天适应每个苏氨酸摄入量是否会改变成年男性的苏氨酸需求，与 1 天适应相比。
方法
11 名健康成年男性（19-35 岁，体重指数（BMI）为 23.4 kg·m）在 6 个苏氨酸摄入量下进行研究；每个摄入量都在 9 天的时间内进行研究。在 2 天适应充足蛋白质摄入（1.0 g·kg·d）后，受试者接受实验饮食，其中包含随机分配的测试苏氨酸摄入量（5、10、15、20、25 或 35 mg·kg·d），持续 7 天。在适应实验饮食的第 1、3 和 7 天进行 IAAO 研究。测量 L-[1-C]苯丙氨酸（FCO）氧化释放的 CO 速率，并通过在 R 版本 4.0.5 中应用混合效应变化点回归来确定苏氨酸需求。使用参数自举法计算 95%置信区间（CI），并使用方差分析（ANOVA）比较第 1、3 和 7 天的需求估计值。
结果
第 1、3 和 7 天的平均苏氨酸需求（上、下 95%CI）分别为 10.5（5.7，15.9）、10.6（7.5，13.7）和 12.1（9.2，15.0）mg·kg·d；这些需求没有统计学差异（P=0.213）。
结论
我们证明，短至 8 小时的 IAAO 方案导致的苏氨酸需求与健康成年男性适应 3 或 7 天获得的需求没有统计学差异。本试验在 www.clinicaltrials.gov 上注册，编号为 NCT04585087。
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