Philpott Jordan D, Bootsma Niels J, Rodriguez-Sanchez Nidia, Hamilton David Lee, MacKinlay Elizabeth, Dick James, Mettler Samuel, Galloway Stuart D R, Tipton Kevin D, Witard Oliver C
Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom.
Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia.
Front Nutr. 2019 Jul 16;6:102. doi: 10.3389/fnut.2019.00102. eCollection 2019.
A detrimental consequence of diet-induced weight loss, common in athletes who participate in weight cutting sports, is muscle loss. Dietary omega-3 polyunsaturated fatty acids (n-3PUFA) exhibit a protective effect on the loss of muscle tissue during catabolic situations such as injury-simulated leg immobilization. This study aimed to investigate the influence of dietary n-3PUFA supplementation on changes in body composition and muscle strength following short-term diet-induced weight loss in resistance-trained men. Twenty resistance-trained young (23 ± 1 years) men were randomly assigned to a fish oil group that supplemented their diet with 4 g n-3PUFA, 18 g carbohydrate, and 5 g protein (FO) or placebo group containing an equivalent carbohydrate and protein content (CON) over a 6 week period. During weeks 1-3, participants continued their habitual diet. During week 4, participants received all food items to control energy balance and a macronutrient composition of 50% carbohydrate, 35% fat, and 15% protein. During weeks 5 and 6, participants were fed an energy-restricted diet equivalent to 60% habitual energy intake. Body composition and strength were measured during weeks 1, 4, and 6. The decline in total body mass (FO = -3.0 ± 0.3 kg, CON = -2.6 ± 0.3 kg), fat free mass (FO = -1.4 ± 0.3 kg, CON = -1.2 ± 0.3 kg) and fat mass (FO = -1.4 ± 0.2 kg, CON = -1.3 ± 0.3 kg) following energy restriction was similar between groups (all > 0.05; d: 0.16-0.39). Non-dominant leg extension 1 RM increased (6.1 ± 3.4%) following energy restriction in FO ( < 0.05, = 0.29), with no changes observed in CON ( > 0.05, = 0.05). Dominant leg extension 1 RM tended to increase following energy restriction in FO ( = 0.09, = 0.29), with no changes in CON ( > 0.05, = 0.06). Changes in leg press 1 RM, maximum voluntary contraction and muscular endurance following energy restriction were similar between groups ( > 0.05, = 0.05). Any possible improvements in muscle strength during short-term weight loss with n-3PUFA supplementation are not related to the modulation of FFM in resistance-trained men.
在参与减体重项目的运动员中，饮食导致的体重减轻所带来的一个有害后果是肌肉流失。在诸如模拟损伤的腿部固定等分解代谢情况下，膳食ω-3多不饱和脂肪酸（n-3PUFA）对肌肉组织的流失具有保护作用。本研究旨在调查膳食补充n-3PUFA对阻力训练男性短期饮食诱导体重减轻后身体成分和肌肉力量变化的影响。20名阻力训练的年轻男性（23±1岁）被随机分配到鱼油组，该组在6周内其饮食补充4克n-3PUFA、18克碳水化合物和5克蛋白质（FO），或分配到安慰剂组，该组含有等量的碳水化合物和蛋白质（CON）。在第1 - 3周，参与者继续他们的习惯饮食。在第4周，参与者收到所有食物以控制能量平衡，且宏量营养素组成为50%碳水化合物、35%脂肪和15%蛋白质。在第5周和第6周，参与者摄入相当于其习惯能量摄入量60%的能量限制饮食。在第1、4和6周测量身体成分和力量。能量限制后，两组间总体重（FO = -3.0±0.3千克，CON = -2.6±0.3千克）、去脂体重（FO = -1.4±0.3千克，CON = -1.2±0.3千克）和脂肪量（FO = -1.4±0.2千克，CON = -1.3±0.3千克）的下降相似（均P>0.05；d：0.16 - 0.39）。FO组在能量限制后非优势腿伸展1RM增加（6.1±3.4%）（P<0.05，d = 0.29），而CON组未观察到变化（P>0.05，d = 0.05）。FO组在能量限制后优势腿伸展1RM有增加趋势（P = 0.09，d = 0.29），CON组无变化（P>0.05，d = 0.06）。两组间能量限制后腿举1RM、最大随意收缩和肌肉耐力的变化相似（P>0.05，d = 0.05）。在阻力训练男性短期体重减轻期间，补充n-3PUFA对肌肉力量的任何可能改善与去脂体重的调节无关。
