Calvez Juliane, Azzout-Marniche Dalila, Tomé Daniel
AgroParisTech, INRAE, Université Paris-Saclay, Paris, France.
Front Nutr. 2024 May 28;11:1406618. doi: 10.3389/fnut.2024.1406618. eCollection 2024.
Dietary proteins are energy macronutrients providing nitrogen, amino acids (AA), and energy. AAs are the main nitrogen-containing compounds in the body and are the precursors for the synthesis of body proteins and of several other AA-derived molecules. Among the 20 AAs included in protein sequence, 9 are classified as "nutritionally essential" or "indispensable" AA (IAA) because they cannot be synthesized in the body and must be provided by the diet. IAAs are limiting components for protein synthesis. An adequate intake of protein is required to support growth, maintenance, body functions, health and survival. Official definition of protein requirement is based on nitrogen balance. Protein quality is related to the capacity of protein to provide an adequate quantity of nitrogen and of each of the 9 IAAs for the different physiological situations in humans. Protein source is considered high quality for humans when the protein is readily digested, simultaneously providing an adequate quantity of nitrogen and of each of the 9 IAAs to maintain an adequate metabolic AA pool. The most accurate assessment of protein quality of foods for humans is through metabolic studies that measure nitrogen balance. The protein quality score is the ratio of the content of each IAA in the food and in a reference profile. This score corresponds to the calculated composition of a protein which, when meeting protein requirements, simultaneously meets the requirements of each of the 9 IAAs. AA scores as predictors of protein quality must be adjusted for protein and AA availability.
膳食蛋白质是提供氮、氨基酸（AA）和能量的能量宏量营养素。氨基酸是体内主要的含氮化合物，是合成身体蛋白质和其他几种氨基酸衍生分子的前体。在蛋白质序列中包含的20种氨基酸中，有9种被归类为“营养必需”或“必需”氨基酸（IAA），因为它们不能在体内合成，必须由饮食提供。必需氨基酸是蛋白质合成的限制成分。需要摄入足够的蛋白质来支持生长、维持身体功能、健康和生存。蛋白质需求的官方定义基于氮平衡。蛋白质质量与蛋白质在不同生理情况下为人体提供足够数量的氮和9种必需氨基酸中每一种的能力有关。当蛋白质易于消化，同时提供足够数量的氮和9种必需氨基酸中的每一种以维持足够的代谢氨基酸池时，该蛋白质来源对人类来说被认为是高质量的。对人类食物蛋白质质量的最准确评估是通过测量氮平衡的代谢研究来进行的。蛋白质质量得分是食物中每种必需氨基酸含量与参考图谱中含量的比值。该得分对应于一种蛋白质的计算组成，当满足蛋白质需求时，同时满足9种必需氨基酸中每一种的需求。作为蛋白质质量预测指标的氨基酸得分必须根据蛋白质和氨基酸的可利用性进行调整。
