The effects of a powdered meal replacement intake on inflammation, gut microbiota, and metabolism compared to habitual diet in people with excess body weight - results from a randomized controlled trial

Abstract

Background: Excess body weight is associated with chronic low-grade inflammation and metabolic abnormalities, such as insulin resistance, and dyslipidemia. Objectives: This study aimed to assess the impact of a soy protein-yogurt-honey powdered meal replacement (PMR) on inflammation, gut microbiota, and metabolism in individuals with excess body weight and in weight-stable conditions. Methods: The Powdered meal REplacement on MetabolIsm and gUt Microbiota (PREMIUM) Study was a 12-week, parallel-arm, randomized controlled trial. Participants (body mass index: 25–37 kg/m2 ) were randomized into either control (CON; usual diet, n = 34) or PMR (2 daily doses added to usual diet, n = 29) groups, maintaining a stable body weight. Assessments occurred at baseline, week 6, and week 12, and included inflammation markers (primary outcome: IL-6), gut microbiota diversity and composition (secondary outcome), metabolic blood markers (glucose and lipid profile), body composition (via dual-energy X-ray absorptiometry), and dietary intake. Data of completers were analyzed by 2-way repeated measures analysis of variance or generalized estimating equations with Bonferroni-corrected post hoc tests. Between-group differences in changes over time are expressed as mean and 95% confidence intervals. Results: Adherence to PMR was 98% of total doses, which increased protein intake [6.53% (5.04%, 8.02%), P < 0.001] and decreased fat intake [− 5.23% (− 7.10%, − 3.35%), P < 0.001] compared with CON. By design, body weight remained stable. There were no changes in IL-6 [− 0.01 (− 0.47, 0.45) pg/mL, P = 0.412], with a low statistical power of 13.7%. Minor changes in gut microbiota composition included an increase in relative abundance of Subdoligranulum (0.72 Log2 fold-change, q = 0.002). In exploratory outcomes, PMR increased lean soft tissue [0.57 (0.12, 1.02) kg, P = 0.014] and reduced total cholesterol [− 0.33 (− 0.58, − 0.08) mmol/L, P = 0.01] and low-density lipoprotein cholesterol [− 0.28 (− 0.46, − 0.10) mmol/L, P = 0.003]. Conclusions: In this population, PMR intake did not improve chronic low-grade inflammation and had limited effects on gut microbiota, but was associated with improvements in lean soft tissue and lipid profile that warrant further exploration.