老年肌肉萎缩怎么办？除了补充蛋白质外，还需要哪些营养？
随着年龄增长，肌肉质量和体重的普遍下降，在临床上被称为肌肉减少症（或少肌症）。老年肌肉减少（或肌肉萎缩）会导致身体虚弱，运动和呼吸能力明显下降，感染、跌倒和过早死亡的风险显著增加，以及总体生活质量降低1。
少肌症的病理机制包括：全身性炎症水平过高、氧化损伤和睾酮等合成代谢激素水平降低，并且可能同时存在2。少肌症与恶病质（或称恶液质、极度消瘦）不同，虽然二者都属于“分解代谢消耗（Catabolic wasting）”范畴，但恶病质主要是指由癌症、艾滋病和慢性阻塞性肺部（COPD）等严重慢性病引起；在许多情况下，恶病质患者即使摄入了足够的热量，也会继续失重3；少肌症则通常指与年龄相关的肌肉质量和功能丧失，大约半数的80岁以上老年人会发生少肌症4。
少肌症也可能是由于缺乏运动、营养不良或疾病（如糖尿病）引起。仅与年龄相关而无其他潜在原因的肌肉损伤被称为“原发性肌肉减少症”，而由一种或多种其他原因引起的肌肉损失则称为“继发性肌肉减少症”2。此外，少肌症有时会发生在仍有大量脂肪储存的人身上，这种情况被称为“肌肉减少性肥胖”（俗称“虚胖”）5。
许多营养、生活方式等干预措施可能有助于预防和控制少肌症。乳清蛋白、肌酸和谷氨酰胺、亮氨酸和羟甲基丁酸（HMB）对于建立和维持瘦肌肉质量尤其重要；欧米伽-3脂肪酸和维生素D等也能对抗瘦肌肉组织的损失。具体简介如下：
来源：本网编辑 2023.07.29.
参考文献：
1. Sirola J, Kroger H. Similarities in acquired factors related to postmenopausal osteoporosis and sarcopenia. J Osteroporos 2011. Doi: 4061/2011/536735
2.Rolland Y et al. Cachexia versus sarcopenia. Curr Opin Clin Nutr Metab Care. 2010;14(1):15-21.
3. Muscaritoli A et al. Muscle atrophy in aging and chronic diseases: is it sarcopenia or cachexia? Intern Emerg Med 2013;8: 553-560.
4. Janssen I et al. Skeletal muscle cutpoints associated with elevated physical disability risk in older men and women. Am J Epidemiol 2004;159(4):413-421.
5. Zamboni M et al. Sarcopenic obesity: A new category of obesity in the elderly. Nutr Metab Cardiovasc Dis. 2008;18(5):388-395.
6. Paddon-Jones D et al. Dietary protein recommendations and the prevention of sarcopenia. Curr Opin Clin Nutr Metab Care. 2009 Jan;12(1):86-90.
7. Lynch HM et al. No Significant Differences in Muscle Growth and Strength Development When Consuming Soy and Whey Protein Supplements Matched for Leucine Following a 12 Week Resistance Training Program in Men and Women: A Randomized Trial. Int J Environ Res Public Health. 2020 May 29;17(11):3871.
8. Molfino A et al. Beta-hydroxy-beta-methylbutyrate supplementation in health and disease: a systematic review of randomized trials. Amino Acids. 2013 Dec;45(6):1273-92.
9. Rawson ES et al. Use of creatine in the elderly and evidence for effects on cognitive function in young and old. Amino Acids. 2011 May;40(5):1349-62.
10. Smith GI et al. Dietary omega-3 fatty acid supplementation increases the rate of muscle protein synthesis in older adults: a randomized controlled trial. Am J Clin Nutr. 2011 Feb;93(2):402-12.
11. Tieland M et al. Low vitamin D status is associated with reduced muscle mass and impaired physical performance in frail elderly people. Eur J Clin Nutr. 2013 Oct;67(10):1050-5.
12. Kinugasa Y et al. Association of carnitine insufficiency with sarcopenia and dynapenia in patients with heart failure. Geriatr Gerontol Int. 2023 Jul;23(7):524-530.
13. Scott D et al. Associations between dietary nutrient intake and muscle mass and strength in community-dwelling older adults: the Tasmanian Older Adult Cohort Study. J Am Geriatr Soc. 2010 Nov;58(11):2129-34.
14. Semba RD et al. Carotenoids as protection against sarcopenia in older adults. Arch Biochem Biophys. 2007 Feb 15;458(2):141-5.
15. Holt PR. Intestinal malabsorption in the elderly. Dig Dis. 2007;25(2):144-50.
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少肌症的病理机制包括：全身性炎症水平过高、氧化损伤和睾酮等合成代谢激素水平降低，并且可能同时存在2。少肌症与恶病质（或称恶液质、极度消瘦）不同，虽然二者都属于“分解代谢消耗（Catabolic wasting）”范畴，但恶病质主要是指由癌症、艾滋病和慢性阻塞性肺部（COPD）等严重慢性病引起；在许多情况下，恶病质患者即使摄入了足够的热量，也会继续失重3；少肌症则通常指与年龄相关的肌肉质量和功能丧失，大约半数的80岁以上老年人会发生少肌症4。
少肌症也可能是由于缺乏运动、营养不良或疾病（如糖尿病）引起。仅与年龄相关而无其他潜在原因的肌肉损伤被称为“原发性肌肉减少症”，而由一种或多种其他原因引起的肌肉损失则称为“继发性肌肉减少症”2。此外，少肌症有时会发生在仍有大量脂肪储存的人身上，这种情况被称为“肌肉减少性肥胖”（俗称“虚胖”）5。
许多营养、生活方式等干预措施可能有助于预防和控制少肌症。乳清蛋白、肌酸和谷氨酰胺、亮氨酸和羟甲基丁酸（HMB）对于建立和维持瘦肌肉质量尤其重要；欧米伽-3脂肪酸和维生素D等也能对抗瘦肌肉组织的损失。具体简介如下：
- 乳清蛋白：增加优质蛋白和氨基酸的摄入对于减缓并可能逆转肌肉损失不可或缺6;支链氨基酸(亮氨酸、异亮氨酸和缬氨酸)在促进肌肉组织生长方面尤其重要。乳清蛋白富含支链氨基酸、精氨酸、谷氨酰胺等必需氨基酸，这是老年预防肌肉减少症的首选，建议补充量：30-50g/天。
- 羟甲基丁酸(HMB): 它是亮氨酸代谢物，可增加肌肉蛋白合成并抑制肌肉分解，尤其是与运动结合时8; 补充（3g/天）可提高与肌肉萎缩相关疾病的老年肌肉力量和质量增加7。
- 肌酸：老年体内肌酸较低，补充（5-20g/天）可显著提高生理性肌酐水平，促进老年运动肌肉力量，并增加瘦肌肉9。
- 鱼油: 有助于预防和治疗肌肉分解代谢，并可促进肌肉蛋白合成。老年人补充鱼油可有效提高蛋白质合成率，并改善老年人手握力量10。鱼油参考用量：5-6g/天（以60%标准鱼油计）。
- 维生素D：维生素D不足（<20ng/ml）与瘦体重减少和体能受损有关11; 维生素D可增强肌肉力量，补充可有效降低老年跌倒率。维生素D缺乏较为常见，一般补充2000-3000IU/天。通常维持最佳健康的血清维生素D水平为：50-80ng/ml。
- L肉碱：肉碱在心力衰竭等慢性病患者中常见缺乏，补充可以防止少肌症12。
- 复合矿物质：充足的矿物质摄入对保持老年人的肌肉质量很重要。许多老年人的饮食摄入量和/或血液中多种矿物质（包括钙、镁、硒、铬和锌）的水平不足。铁、镁、麟、钾和锌等矿物质摄入量越高，其手臂、腿部和瘦肌肉量就越大13。
- 类胡萝卜素：研究表明，血液中类胡萝卜素含量较低与肌肉质量和力量显著减少以及行走障碍显著增加有关14。常见的类胡萝卜素包括β-胡萝卜素、叶黄素和番茄红素等。
- 消化酶：肌肉萎缩患者可能受益于口服消化酶补充剂。多项研究报告称，与年轻人相比，老年人的胰腺酶（即消化蛋白质、脂肪和碳水化合物的酶）水平更低15。补充可促进食物消化和吸收，改善营养状况。
来源：本网编辑 2023.07.29.
参考文献：
1. Sirola J, Kroger H. Similarities in acquired factors related to postmenopausal osteoporosis and sarcopenia. J Osteroporos 2011. Doi: 4061/2011/536735
2.Rolland Y et al. Cachexia versus sarcopenia. Curr Opin Clin Nutr Metab Care. 2010;14(1):15-21.
3. Muscaritoli A et al. Muscle atrophy in aging and chronic diseases: is it sarcopenia or cachexia? Intern Emerg Med 2013;8: 553-560.
4. Janssen I et al. Skeletal muscle cutpoints associated with elevated physical disability risk in older men and women. Am J Epidemiol 2004;159(4):413-421.
5. Zamboni M et al. Sarcopenic obesity: A new category of obesity in the elderly. Nutr Metab Cardiovasc Dis. 2008;18(5):388-395.
6. Paddon-Jones D et al. Dietary protein recommendations and the prevention of sarcopenia. Curr Opin Clin Nutr Metab Care. 2009 Jan;12(1):86-90.
7. Lynch HM et al. No Significant Differences in Muscle Growth and Strength Development When Consuming Soy and Whey Protein Supplements Matched for Leucine Following a 12 Week Resistance Training Program in Men and Women: A Randomized Trial. Int J Environ Res Public Health. 2020 May 29;17(11):3871.
8. Molfino A et al. Beta-hydroxy-beta-methylbutyrate supplementation in health and disease: a systematic review of randomized trials. Amino Acids. 2013 Dec;45(6):1273-92.
9. Rawson ES et al. Use of creatine in the elderly and evidence for effects on cognitive function in young and old. Amino Acids. 2011 May;40(5):1349-62.
10. Smith GI et al. Dietary omega-3 fatty acid supplementation increases the rate of muscle protein synthesis in older adults: a randomized controlled trial. Am J Clin Nutr. 2011 Feb;93(2):402-12.
11. Tieland M et al. Low vitamin D status is associated with reduced muscle mass and impaired physical performance in frail elderly people. Eur J Clin Nutr. 2013 Oct;67(10):1050-5.
12. Kinugasa Y et al. Association of carnitine insufficiency with sarcopenia and dynapenia in patients with heart failure. Geriatr Gerontol Int. 2023 Jul;23(7):524-530.
13. Scott D et al. Associations between dietary nutrient intake and muscle mass and strength in community-dwelling older adults: the Tasmanian Older Adult Cohort Study. J Am Geriatr Soc. 2010 Nov;58(11):2129-34.
14. Semba RD et al. Carotenoids as protection against sarcopenia in older adults. Arch Biochem Biophys. 2007 Feb 15;458(2):141-5.
15. Holt PR. Intestinal malabsorption in the elderly. Dig Dis. 2007;25(2):144-50.