Dairy milk matrix modulation of inflammation and muscle protein synthesis in adults with excess adiposity

Obesity is associated with anabolic resistance of muscle protein synthesis rates (MPS) to protein ingestion, which impairs skeletal muscle protein remodeling. The factors leading to the impaired MPS are multifaceted, but likely chronic inflammation plays a role. As such, nutritional strategies aimed at eliciting robust MPS responses are important for managing obesity as they will help ensure a protein pool of high metabolic quality. Indeed, dairy milk may represent a particularly favorable protein food choice for obesity management due to its high-quality protein and bioactive lipid components, contributing to a unique food matrix. Therefore, this dissertation aimed to examine (AIM 1) the effect of dairy milk matrix manipulations on acute postprandial MPS using primed constant stable isotope methods and muscle biopsy collections, (AIM 2) the postprandial systemic and muscle inflammatory response, (AIM 3) 7-day integrated MPS based on the D2O method, and (AIM 4) 7-day changes in inflammatory markers in individuals with excess adiposity. To accomplish these dissertation AIMS, thirty-three overweight and obese participants (BMI ≥25 kg∙m-2) were block-randomized to full-fat milk (FFD; n=12), non-fat milk (NFD; n=11), or isonitrogenous, macronutrient-matched non-dairy control beverage (CTL; n=10) conditions. For AIMS 3-4, a 7-day, fully controlled, dietary intervention was utilized, with each participant consuming dairy milk (FFD or NFD) or the control beverage 3 times daily for 7 days. For AIMS 1-2, an acute feeding trial was conducted following the final day of the 7-day intervention, with participants ingesting 2 servings of dairy milk (FFD or NFD) or the control beverage. Acutely, only the CTL condition significantly elevated postprandial MPS during the 5-hour postprandial period (P < 0.001). CLT was also associated with higher plasma leucine availability (i.e., plasma leucine Cmax and early (2H) iAUC were significantly higher in CTL than FFD (P = 0.041; P = 0.004, respectively)) and increased AKTThr308 phosphorylation at 120 min (P = 0.019). Postprandial plasma IL-6 increased significantly at 300 min in CTL and NFD groups (P = 0.028; P = 0.043, respectively), while intramuscular NF-κB phosphorylation was elevated at 300 min only in the FFD group (P = 0.003). No differences were observed in 7-day integrated myofibrillar fractional synthetic rates (FSR) (P = 0.939) or fasting systemic or intramuscular inflammatory markers between groups (all P > 0.05). Thus, this dissertation demonstrated that neither FFD nor NFD conditions induced superior anabolic or anti-inflammatory benefits compared to the CTL. These findings suggest that in individuals with excess adiposity, when consuming moderate amounts of protein (2 servings of dairy; >17g protein), free amino acid-based beverages stimulate acute MPS more effectively than dairy milk. Yet, this was not reflected over a longer (7 days) period. Similarly, acute perturbation in postprandial inflammation did not modify fasted inflammation markers following a 7-day intervention.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Kinesiology

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Barnes, Takeshi Matsunae

Contributors dc:contributor

• Burd, Nicholas A.
• Burd, Nicholas A
• Wilund, Kenneth R
• Allen, Jacob M
• Moore, Daniel R.

• Protein Metabolism
• Muscle Protein Synthesis
• Inflammation
• Obesity
• Dairy
• Clinical Nutrition

Statement dc:rights

• Copyright 2025 Takeshi Barnes

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129899

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129899