Background: The gut microbiota plays a fundamental role in metabolic and immune homeostasis through the production of short-chain fatty acids (SCFAs). These metabolites influence mitochondrial biogenesis, muscle energetics, epithelial barrier stability, and inflammatory regulation via G-protein-coupled receptors, AMPK–PGC-1α signaling, and epigenetic remodeling. Objective: This review synthesizes current evidence on the gut–muscle–immune axis, emphasizing how dietary fermentable substrates, microbial cross-feeding interactions, and structured exercise modulate SCFA production and shape host physiological adaptation. Methods: We integrated findings from human and animal studies, multi-omic analyses, metabolomic and microbiome research, and exercise physiology to outline mechanistic links between microbial metabolism and systemic resilience. Results: Key mechanistic pathways connecting dietary fiber fermentation to mitochondrial function, redox regulation, immune homeostasis, and metabolic plasticity are summarized. We further present the Targeted Gut Protocol 2.0, a conceptual 12-week framework combining fiber-diversity targets, lactate-guided exercise periodization, biomarker monitoring, and adaptive feedback mechanisms to enhance endogenous SCFA availability. Conclusions: SCFA-driven metabolic plasticity provides an integrative model through which lifestyle behaviors can modulate host physiology. Future research should prioritize standardized sampling approaches, causal inference methods, multi-omic integration, and AI-supported personalization to refine mechanistic understanding and strengthen translational potential.

Purpose: In recent decades studies have examined body weight changes following tonsillectomy. In nutrition science, the focus has shifted from body mass index to body composition analysis. However, no studies have explored body composition changes post-tonsillectomy. In oncology and digestive surgeries, the potential benefits of branched-chain amino acids (BCAAs) have been investigated; however, their effects on pharyngeal surgery remain unknown. Therefore, the aim of the present study was to investigate the body composition changes after tonsillectomy and to explore the potential benefits of branched-chain amino acids. Methods: This prospective interventional controlled study enrolled 48 patients who were randomly assigned to a control group (CG) and an experimental group (EG). These groups were further divided into active and inactive subgroups on the basis of their activity levels. The EG consumed 2 × 4 mg of BCAA daily. Body composition was measured using bioimpedance (InBody 270) on the day of surgery and again on days 7 and 21 postoperatively. Results: Both groups experienced similar weight loss; however, significant differences in body composition emerged. The CG showed significant muscle mass loss (from 30,29 to 28,51 kg), whereas active EG members maintained muscle mass (from 35,33 to 35,40 kg); inactive EG members increased muscle mass (from 26,70 to 27,56 kg) and reduced body fat percentage (from 31.94% to 29.87%). The general health status (InBody score) remained stable or improved in the EG (from 75,13 to 75,96); however, it decreased in the CG (from 75,42 to 72,67). Conclusion: The negative effects of tonsillectomy on body composition are mitigated by BCAA supplementation.

The most commonly used method for determining nutritional status to date is the BMI (Body Mass Index). From a scientific point of view, as it is based only on body weight and height, it can be misleading in many cases and is of limited use for the professional assessment of health status and obesity. Today there are more modern and accurate methods. Bioimpedance-based body composition assessment (BIA) systems provide detailed information on body weight, muscle and fat mass and water content. The frequency ranges and measurement points used have a major impact on the accuracy of the measurement data, and the Inbody series excels in this respect. Unlike other devices, it can also provide lean body mass and fat mass broken down by limb. Changes in nutritional status can be used as a predictor of disease progression, so the results of body composition measurement have applications in many areas of healthcare. Examples include diet therapy, obesity management, perioperative care, sports nutrition, supplementation of various therapies (oncology, nephrology, diabetology, cardiology, etc.), rehabilitation. Considering all these factors, it would be worthwhile to extend the use of BIA-based devices to the field of primary prevention (e.g. general practitioners, population screening, workplace health promotion).

Upper airway function has received limited attention as a potentially relevant component of respiratory physiology in aquatic athletes. Repeated exposure to chlorinated indoor environments, combined with high ventilatory demand during training, may contribute to the development of chronic irritant rhinitis characterized by nasal obstruction and mucosal hyperreactivity. Although often perceived as a minor inconvenience, increased nasal resistance may influence breathing comfort, perceived exertion, and recovery stability in swimmers and other aquatic athletes. In addition to environmental exposure, the widespread use of topical nasal decongestants may result in rebound congestion and rhinitis medicamentosa, thereby contributing to a self-reinforcing cycle of airway dysfunction. Performance-related pressure and uncertainty related to anti-doping regulations may further shape medication behavior within athletic environments. This narrative review integrates environmental exposure mechanisms, mucosal pathophysiology, and behavioral medication patterns to provide a unified conceptual framework for understanding upper airway dysfunction in aquatic athletes. Particular emphasis is placed on nasal airflow stability as a potentially relevant factor in breathing comfort, sleep quality, and training consistency. Given that the available evidence is predominantly mechanistic and observational, the proposed relationships should be interpreted as hypothesis-generating and translational rather than as evidence of direct causal effects on athletic performance.

Head and neck cancer represents one of the most nutritionally vulnerable oncologic populations, driven by tumor-related functional impairment, treatment toxicities, and complex metabolic alterations. Malnutrition and skeletal muscle loss are highly prevalent at diagnosis and frequently worsen during therapy, impairing treatment tolerance, functional status, and clinical outcomes. This narrative review synthesizes clinical and mechanistic evidence on the interrelated roles of malnutrition, low skeletal muscle mass, mucosal toxicity, and systemic inflammation across the perioperative, definitive treatment, and post-acute recovery phases. Particular emphasis is placed on the limitations of body mass index-based assessment and the importance of integrating validated screening tools with context-appropriate phenotypic evaluation of muscle depletion. Beyond conventional energy replacement, we examine the evidence supporting perioperative immunonutrition, discuss the contextual limitations of immune-modulating strategies during chemoradiotherapy, and consider emerging adjunctive metabolic approaches. Mucositis is conceptualized not only as a local toxicity but also as a contributor to reduced intake and inflammation-driven catabolism. The post-treatment phase is highlighted as a critical period for continued monitoring of body composition and functional recovery. Collectively, the available evidence supports a shift from weight-centered nutritional paradigms toward an integrated, body composition-oriented and inflammation-aware framework for supportive care in head and neck oncology.