Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults
Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults
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DOI：
10.1093/ajcn/78.2.250
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发表时间：
2003-08-01
影响因子：
7.1
通讯作者：
Wolfe, RR
中科院分区：
文献类型：
--
作者：
Volpi, E;Kobayashi, H;Wolfe, RR
背景：营养补充剂可用于治疗随年龄增长的肌肉损失（肌肉减少症）。然而，如果身体活动没有增加，老年人往往会通过减少食物摄入来补偿补充剂提供的增加的能量，这导致热量替代而不是补充。因此，有效的补充剂应该比食物或普通蛋白质补充剂更有效地刺激肌肉。我们已经证明，平衡的氨基酸刺激肌肉蛋白质analgesia在老年人，但它是未知的，是否所有的氨基酸是必要的，以实现这一效果。目的：我们评估是否需要非必需氨基酸的营养补充剂，以刺激肌肉蛋白质analgesia在老年人。设计：我们比较了肌肉蛋白质代谢的反应，无论是18克必需氨基酸（EAA组：n = 6，年龄69+/-2岁;（x）高于标准差+/- SD）或40 g平衡氨基酸（18 g必需氨基酸+22 g非必需氨基酸，BAA组; n = 8，年龄71 +/- 2岁），每10分钟口服一次，持续3 h。肌肉蛋白质代谢在基础状态下和在氨基酸给药期间通过L-[环-H-2（5）]苯丙氨酸输注、股动脉和静脉导管插入术和肌肉活检来测量。min（-1）。100 mL腿部体积（-1））从基础状态增加（P < 0.01），组间无差异（BAA：从-16 +/- 5到16 +/- 4; EAA：从-18 +/- 5到14 +/- 13），因为增加结论：必需氨基酸是氨基酸刺激老年人肌肉蛋白质合成的主要因素。
Background: Nutritional supplementation may be used to treat muscle loss with aging (sarcopenia). However, if physical activity does not increase, the elderly tend to compensate for the increased energy delivered by the supplements with reduced food intake, which results in a calorie substitution rather than supplementation. Thus, an effective supplement should stimulate muscle anabolism more efficiently than food or common protein supplements. We have shown that balanced amino acids stimulate muscle protein anabolism in the elderly, but it is unknown whether all amino acids are necessary to achieve this effect.Objective: We assessed whether nonessential amino acids are required in a nutritional supplement to stimulate muscle protein anabolism in the elderly.Design: We compared the response of muscle protein metabolism to either 18 g essential amino acids (EAA group: n = 6, age 69+/-2 y; (x) over bar +/- SD) or 40 g balanced amino acids (18 g essential amino acids + 22 g nonessential amino acids, BAA group; n = 8, age 71 +/- 2 y) given orally in small boluses every 10 min for 3 h to healthy elderly volunteers. Muscle protein metabolism was measured in the basal state and during amino acid administration via L-[ring-H-2(5)]phenylalanine infusion, femoral arterial and venous catheterization, and muscle biopsies.Results: Phenylalanine net balance (in nmol . min(-1) . 100 mL leg volume(-1)) increased from the basal state (P < 0.01), with no differences between groups (BAA: from -16 +/- 5 to 16 +/- 4; EAA: from -18 +/- 5 to 14 +/- 13) because of an increase (P < 0.01) in muscle protein synthesis and no change in breakdown.Conclusion: Essential amino acids are primarily responsible for the amino acid-induced stimulation of muscle protein anabolism in the elderly.