Assessment of protein requirement in octogenarian women with use of the indicator amino acid oxidation technique
Assessment of protein requirement in octogenarian women with use of the indicator amino acid oxidation technique
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DOI：
10.3945/ajcn.112.042325
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发表时间：
2014-04-01
影响因子：
7.1
通讯作者：
Campbell, Wayne W.
中科院分区：
文献类型：
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作者：
Tang, Minghua;McCabe, George P.;Campbell, Wayne W.
背景：关于老年人蛋白质需求的数据有限，因为在这些脆弱人群中重复进行氮平衡方案是不切实际的。目的：本研究旨在通过使用最近开发的微创指示氨基酸氧化（IAAO）技术来确定老年女性的膳食蛋白质需求。设计：6名80-87岁的白人女性[平均值+/-SEM：82+/-1岁和体重指数（以kg/m(2)为单位）26+/-2]完成3-d 协议 7 次。每个女性连续 2 天食用适应饮食，并在第 3 天食用完整的测试饮食，其中含有随机测试的 7 种蛋白质摄入量中的一种（0.1、0.3、0.6、0.9、1.2、1.5 或 1.8 g.kg(-1).d(-1)）中的一种结晶氨基酸混合物。通过使用蛋白质摄入和 L-[1-C-13]苯丙氨酸氧化的非线性混合模型来评估基于群体的蛋白质需求。将呼吸中 C-13 出现率不再下降的断点用作平均蛋白质需求量的指标。 结果：平均蛋白质需求量 (95% CI) 为 0.85 (0.60, 1.09) g。千克（-1）。 d(-1)。这一要求比目前成人的估计平均需要量 (EAR) 0.66 克高 29%。千克（-1）。 d(-1) 基于氮平衡技术，尽管 95% CI 包括当前的 EAR。相应的充足蛋白质摄入量为1.15（0.77，1.54）g。千克（-1）。尽管 95% CI 包括 0.80 g 的推荐膳食摄入量 (RDA)，但 d(-1) 仍高出 44%。千克（-1）。 d(-1).结论：尽管使用 IAAO 技术评估蛋白质需求的有效性存在不确定性，但这项针对八旬妇女的研究结果表明，当前老年妇女的 EAR 和 RDA 可能被低估。这种短期、非侵入性方法的局限性凸显了需要使用替代实验设计并测量生理、形态和健康相关结果的新研究。该试验已在临床试验中注册。政府编号为 NCT01193946。
Background: Data on the protein requirements of elderly adults are limited, because it is impractical to conduct repeated nitrogen balance protocols in these vulnerable humans.Objective: This study was designed to determine the dietary protein requirement of elderly women by using the recently developed minimally invasive indicator amino acid oxidation (IAAO) technique.Design: Six white women aged 80-87 y [mean +/- SEM: 82 +/- 1 y and body mass index (in kg/m(2)) 26 +/- 2] completed a 3-d protocol 7 times. Each woman consumed an adaptation diet for 2 d and on day 3 consumed a complete test diet with a crystalline amino acid mixture containing 1 of 7 protein intakes (0.1, 0.3, 0.6, 0.9, 1.2, 1.5, or 1.8 g . kg(-1) . d(-1)) tested randomly. A group-based protein requirement was assessed by using a nonlinear mixed model of protein intake and L-[1-C-13]phenylalanine oxidation. The breakpoint, at which there was no further decline in the rate of appearance of C-13 in the breath, was used as an index of the mean protein requirement.Results: The mean protein requirement (95% CI) was 0.85 (0.60, 1.09) g . kg(-1) . d(-1). This requirement is 29% higher than the current Estimated Average Requirement (EAR) for adults of 0.66 g . kg(-1) . d(-1) based on the nitrogen balance technique, although the 95% CI includes the current EAR. The corresponding adequate protein allowance of 1.15 (0.77, 1.54) g . kg(-1) . d(-1) is 44% higher, although the 95% CI includes the Recommended Dietary Allowance (RDA) of 0.80 g . kg(-1) . d(-1).Conclusions: Notwithstanding uncertainty about the validity of the use of the IAAO technique to assess protein requirements, the results of this study with octogenarian women suggest that the current EAR and RDA for elderly women may be underestimated. The limitations of this short-term, noninvasive method underscore the need for new research that uses alternative experimental designs and measuring physiologic, morphologic, and health-related outcomes. This trial was registered at clinicaltrials. gov as NCT01193946.