Department of Nutrition and Integrative Physiology, University of Utah, 250 S 1850 E, Salt Lake City, UT 84112, USA.
Department of Physical Therapy and Athletic Training, University of Utah, 520 Wakara Way, Salt Lake City, UT 84108, USA.
Nutrients. 2021 Feb 13;13(2):614. doi: 10.3390/nu13020614.
Cheddar cheese is a protein-dense whole food and high in leucine content. However, no information is known about the acute blood amino acid kinetics and protein anabolic effects in skeletal muscle in healthy adults. Therefore, we conducted a crossover study in which men and women ( = 24; ~27 years, ~23 kg/m) consumed cheese (20 g protein) or an isonitrogenous amount of milk. Blood and skeletal muscle biopsies were taken before and during the post absorptive period following ingestion. We evaluated circulating essential and non-essential amino acids, insulin, and free fatty acids and examined skeletal muscle anabolism by mTORC1 cellular localization, intracellular signaling, and ribosomal profiling. We found that cheese ingestion had a slower yet more sustained branched-chain amino acid circulation appearance over the postprandial period peaking at ~120 min. Cheese also modestly stimulated mTORC1 signaling and increased membrane localization. Using ribosomal profiling we found that, though both milk and cheese stimulated a muscle anabolic program associated with mTORC1 signaling that was more evident with milk, mTORC1 signaling persisted with cheese while also inducing a lower insulinogenic response. We conclude that Cheddar cheese induced a sustained blood amino acid and moderate muscle mTORC1 response yet had a lower glycemic profile compared to milk.
切达干酪是一种高蛋白的全食物,富含亮氨酸。然而,目前尚不清楚其在健康成年人中对急性血液氨基酸动力学和骨骼肌蛋白合成代谢的影响。因此,我们进行了一项交叉研究,纳入了男性和女性(=24;27 岁,23kg/m),他们分别摄入奶酪(20g 蛋白质)或等量的牛奶。在摄入后吸收期前后,采集了血液和骨骼肌活检样本。我们评估了循环必需和非必需氨基酸、胰岛素和游离脂肪酸,并通过 mTORC1 细胞定位、细胞内信号和核糖体谱分析来检测骨骼肌合成代谢。我们发现,奶酪摄入后,支链氨基酸的循环出现速度较慢,但持续时间更长,在 120 分钟左右达到峰值。奶酪还适度地刺激了 mTORC1 信号通路,增加了膜定位。通过核糖体谱分析,我们发现,虽然牛奶和奶酪都能刺激与 mTORC1 信号通路相关的肌肉合成代谢程序,但牛奶的作用更明显,而奶酪则能在诱导较低的胰岛素反应的同时,维持 mTORC1 信号通路的活性。我们的结论是,与牛奶相比,切达干酪虽然能引起持续的血液氨基酸和适度的肌肉 mTORC1 反应,但血糖水平较低。