Bagheri Reza, Shakibaee Abolfazl, Camera Donny M, Sobhani Vahid, Ghobadi Hamid, Nazar Eisa, Fakhari Hadi, Dutheil Fred
Exercise Physiology Research Center, Lifestyle Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
Department of Health and Biostatistics, Swinburne University, Melbourne, VIC, Australia.
Front Nutr. 2023 Jun 29;10:1205310. doi: 10.3389/fnut.2023.1205310. eCollection 2023.
The effects of a high protein diet in combination with chronic resistance training (RT) on skeletal muscle adaptation responses in untrained older ex-military men is unknown. Therefore, we compared the effects of 8 weeks of RT in combination with either a high (1.6 g/kg/d) or low protein diet (0.8 g/kg/d) on body composition [skeletal muscle mass (SMM) and body fat percentage (BFP)], muscular strength, power, and endurance (upper and lower body), markers of liver [alanine transaminase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT)] and kidney (creatinine and urea) function, and lipid profile low-density lipoprotein (LDL), high-density lipoprotein (HDL), and cholesterol levels in a cohort of healthy, untrained older ex-military males.
Forty healthy untrained older ex-military males (age: 61 ± 2 yr, body mass index: 23.2 ± 1.3 kg.m) performed 8 weeks (three sessions·w) of RT with either 1.6 g/kg/d (RHP; = 20) or 0.8 g/kg/d of protein (RLP; = 20). Body composition (assessed by Inbody 720), muscular strength (1-RM for chest and leg press), power (Wingate test), endurance (75% 1-RM for chest and leg press), and markers of liver and kidney function (biochemical kits) were assessed pre and post-intervention.
SMM and muscular strength (upper and lower body) increased post-intervention in both groups and were significantly greater in RHP compared to RLP, while muscular power increased to the same extent in both groups ( < 0.05) with no between-group differences ( > 0.05). In contrast, there were no post-intervention changes in muscular endurance, HDL, and BFP remained in either group ( > 0.05). ALT and creatinine significantly increased in RHP compared to RLP while GGT, AST, and urea only increased in the RLP group ( < 0.05). LDL and cholesterol significantly decreased in both groups ( < 0.05).
A daily intake of 1.6 g/kg/d protein was superior to 0.8 g/kg/d (current recommended daily intake) for promoting greater improvements in SMM and muscle strength and thus may be a more suitable level of intake for promoting such adaptive responses. Notwithstanding observed between-group differences in ALT and creatinine and the fact that levels remained within normal ranges, it is feasible to conclude that this daily protein intake is efficacious and well tolerated by healthy, untrained older ex-military males.
高蛋白饮食与慢性抗阻训练（RT）相结合对未受过训练的老年退伍军人骨骼肌适应性反应的影响尚不清楚。因此，我们比较了8周RT联合高蛋白质饮食（1.6 g/kg/天）或低蛋白质饮食（0.8 g/kg/天）对身体成分[骨骼肌质量（SMM）和体脂百分比（BFP）]、肌肉力量、功率和耐力（上身和下身）、肝脏标志物[丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）和γ-谷氨酰转移酶（GGT）]以及肾脏（肌酐和尿素）功能，以及一组健康、未受过训练的老年退伍男性的血脂谱[低密度脂蛋白（LDL）、高密度脂蛋白（HDL）和胆固醇水平]的影响。
40名健康、未受过训练的老年退伍男性（年龄：61±2岁，体重指数：23.2±1.3 kg·m）进行8周（每周3次训练）的RT，其中一组摄入1.6 g/kg/天的蛋白质（RHP；n = 20），另一组摄入0.8 g/kg/天的蛋白质（RLP；n = 20）。在干预前后评估身体成分（通过Inbody 720评估）、肌肉力量（卧推和腿举的1次重复最大值）、功率（温盖特测试）、耐力（卧推和腿举的75% 1次重复最大值）以及肝脏和肾脏功能标志物（生化试剂盒）。
两组干预后SMM和肌肉力量（上身和下身）均增加，且RHP组显著高于RLP组，而两组肌肉功率增加程度相同（P < 0.05），组间无差异（P > 0.05）。相比之下，两组干预后肌肉耐力、HDL均无变化，两组BFP均保持不变（P > 0.05）。与RLP组相比 RHP组ALT和肌酐显著增加，而GGT、AST和尿素仅在RLP组增加（P < 0.05）。两组LDL和胆固醇均显著降低（P < 0.05）。
每日摄入1.6 g/kg/天的蛋白质在促进SMM和肌肉力量更大改善方面优于0.8 g/kg/天（当前推荐的每日摄入量），因此可能是促进此类适应性反应更合适的摄入量水平。尽管观察到组间ALT和肌酐存在差异，且水平仍在正常范围内，但可以得出结论，这种每日蛋白质摄入量对健康、未受过训练的老年退伍男性是有效且耐受性良好的。
