Effects of a High-Protein Diet Including Whole Eggs on Muscle Composition and Indices of Cardiometabolic Health and Systemic Inflammation in Older Adults with Overweight or Obesity: A Randomized Controlled Trial.

Christian Wright,Jing Zhou,Wayne Campbell,Jung Kim,R Sayer

doi:10.3390/nu10070946

Abstract

Age-related increases in intermuscular adipose tissue (IMAT) impair muscle quality, decrease functional capacity, and promote several cardiometabolic and inflammatory disorders. Whether these age-related alterations in muscle composition improve by consuming a high-protein (HP) diet with whole eggs are unclear. This parallel-design, randomized-controlled trial assessed the effects of a 12-week eucaloric HP diet with three whole eggs per day (1.4 g protein kg−1 day−1) versus a normal-protein diet void of eggs (NP, 0.8 g protein kg−1 day−1) on muscle composition (IMAT), cardiometabolic health, and systemic inflammation in older adults with overweight or obesity (12 men and 10 women; age 70 ± 5 years, BMI 31.3 ± 3.2 kg/m2, mean ± SD). No changes in muscle composition were observed over time, independent of protein intake. Total body weight was reduced in both groups (−3.3 ± 1.2%) and lean mass was preserved only with the HP diet. LDL concentration and hip circumference decreased only with the NP diet, while MCP-1 and HsCRP concentrations increased over time in both groups. A HP diet with whole eggs promotes lean mass retention with modest weight loss, but does not positively influence muscle composition, cardiometabolic health or systemic inflammation, compared to a NP diet void of eggs.

Highlights

Ectopic adipose tissue accumulation is an important hallmark of metabolic dysfunction and chronic disease
Intermuscular adipose tissue (IMAT), adipose tissue located beneath the fascia and between muscle fibers and groups, impairs muscle quality and reduces insulin-stimulated skeletal muscle glucose uptake [15,16]
As such, increased intermuscular adipose tissue (IMAT) is associated with insulin resistance [2,3,5,10,17], systemic inflammation [18,19], and skeletal muscle dysfunction, which is characterized by decreased muscle strength [20,21,22,23,24], function [25,26,27], and mobility [22,26,27,28]

Summary

Introduction

Ectopic adipose tissue accumulation is an important hallmark of metabolic dysfunction and chronic disease. Nutrients 2018, 10, 946 located at ectopic sites like skeletal muscle, liver, or the intra-abdominal cavity are strongly associated with chronic inflammation [7,12], impaired glucose tolerance [1,2,3,13] and hyperlipidemia [5,14]. The effect of diet composition on IMAT concentrations in the absence of weight loss or with only modest weight loss has received little attention. This is of particular importance for older adults, a population prone to IMAT accumulation, where excessive weight loss may further impair muscle health and increase the symptoms of sarcopenia [34]. Higher protein intakes are associated with improvements in body composition [35,36], glucose tolerance [37], inflammatory status [38,39], and postprandial lipemia [40,41]

Methods

Results

Discussion

Conclusion