Whey Proteins-Fortified Milk with Adjusted Casein to Whey Proteins Ratio Improved Muscle Strength and Endurance Exercise Capacity without Lean Mass Accretion in Rats.

Eun Woo Jeong,Hyeon Gyu Lee,Gyu Ri Park,Jiyun Kim,Youjin Baek,Gwang-Woong Go

doi:10.3390/foods11040574

Abstract

This study investigated the effects of the casein to whey proteins (CW) ratio in milk on body composition, muscle strength, and endurance exercise capacity in rats. Thirty rats were assigned into five groups, and each treatment was administered for eight weeks: (1) control (isocaloric lactose supplementation), (2) CW8:2 (regular milk), (3) CW6:4, (4) CW5:5, and (5) nitrogen-free (lactose). The milk concentration was converted from a human equivalent dose (400 mL/60 kg body weight/day). All the milk-administered groups showed significantly greater growth performance, including body weight and weight gain compared to the isocaloric lactose control (p < 0.05). However, different CW ratios in milk had no effect on growth performance. Additionally, body composition, i.e., lean body mass and adiposity, was not affected by the CW ratio. Interestingly, CW6:4 and CW5:5 had significantly higher plasma branched-chain amino acids concentrations than control and CW8:2 (p < 0.05). In addition, CW5:5 showed significantly increased grip strength by 12–24% and time to exhaustion by 8–62% compared to the other groups (p < 0.05), indicating that the higher whey proteins ratio improved physical performance. We concluded that whey proteins-fortified milk enhances muscle strength and endurance exercise capacity without altering lean mass in rats.

Highlights

Accepted: 13 February 2022Milk plays an important role in human nutrition as a source of various essential nutrients such as protein and minerals [1]
In our previous study, we reported that different casein to whey proteins (CW) compositions of the experimental diet did not alter body weight and weight gain [20]
We evaluated the effect of the adjusted CW ratio on protein digestibility

Summary

Introduction

Milk plays an important role in human nutrition as a source of various essential nutrients such as protein and minerals [1]. As consumers are increasingly aware of the importance of protein consumption for health, milk has been emerging as a convenient protein source. Cow’s milk has a unique protein composition in that casein and whey proteins account for 80% and 20% of milk protein, respectively [4]. Both casein and whey are nutritionally high-quality proteins compared to plant-based proteins due to their complete essential amino acid profiles and high digestibility [5]. Casein inhibits muscle protein breakdown and contributes to moderate but prolonged muscle

Methods

Results

Conclusion