Sufficient protein intake is essential for adequate physical condition and athletic performance. However, numerous factors can influence the absorption of consumed protein, including timing, type of protein intake, and gut microbiota. In the present study, elite male water polo players consumed a plant-based, vegan protein supplement with (n = 10) or without (n = 10) pre- and probiotics daily during the 31-day study period. We determined the anthropometric characteristics and body composition, dietary habits, gut microbiota composition, and blood parameters of the players at the beginning and at the end of the study. Body composition parameters were analyzed using the InBody 970 bioimpedance analyzer. Gut microbiome composition was determined from stool samples by metagenome sequencing. Paired and unpaired t-tests were used to determine differences between body composition and blood parameters within the groups and between the two groups at the two different sampling times. The Wilcoxon test was used to determine the change in bacterial composition during the study. Correlations between changes in body composition, blood parameters, and taxonomic groups were analyzed using a linear correlation calculation. Skeletal muscle mass (p < 0.001), body cell mass (p = 0.002), arm circumference (p = 0.003), and protein mass (p < 0.001) increased, while body fat mass (p = 0.004) decreased significantly in the intervention group which consumed pre- and probiotics in addition to protein supplement. Activated acetate (reductive TCA cycle I) and propionate (pyruvate fermentation to propanoate I) pathways correlated positively with increased skeletal muscle mass (p < 0.01 and p < 0.05), and the relative abundance of butyrate-producing species showed a significant positive correlation with changes in body fat mass in the intervention group (p < 0.05). These correlations were not observed in the control group without the intake of pre- and probiotics. The composition of the gut microbiota may influence protein absorption and therefore body composition and consequently physical condition and sports performance.

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.

Water polo is unique among aquatic—and generally other—sports as it includes cyclic elements typical in swimming and acyclic elements occurring mainly in ball games. Moreover, water polo demands high level of technical and tactical skills. Players need an optimal nutritional and physical condition to achieve high athletic performance, which is to a great extend influenced by nutritional habits. We aim to highlight possible shortfalls in players’ nutritional intake in relation to positions played within the team. In the present study, we determined the anthropometric and body composition characteristics, dietary habits and laboratory parameters of elite adult male water polo players (n = 19) before the start of the championship and at the end of the regular season, which meant a 4-month intervention period. Analyses of body composition characteristics and nutritional habits were performed using bioimpedance analyzer InBody 770 and a 3-day nutrition diary, respectively. Paired-sample t-test were used to determine the differences between the variables measured before and after the championship. Correlations between the anthropometric and body composition characteristics and different serum parameters were analyzed using linear correlation calculation. K-mean cluster analysis was performed using the anthropometric and body composition characteristics of the athletes. Based on anthropometric and body composition characteristics, players can be divided into two significantly different clusters that shows an association with specific playing positions. Cluster I included goalkeepers and wing players, while defenders, centers, and shooters belonged to Cluster II. We observed significant differences in the physical composition and slight but not significant differences in nutritional habits of the clusters. Cluster I players were 5 cm shorter on average, while their mean body weight, skeletal muscle mass and body fat mass data were lower by 19 kg, 7 kg, and 7 kg, respectively. We studied the correlation between initial anthropometric and body composition parameters and the changes in laboratory parameters before and after the regular season. As a result, we detected numerous significant differences between the two clusters, such as the changes in glucose and magnesium levels, which showed a strong correlation with several body composition parameters in cluster II, but did not in cluster I. Cluster differences between anthropometric and body compositional characteristics, and the changes in laboratory parameters can help to develop position-specific training and nutritional recommendations in the future. Therefore, the results may be applicable in sport sciences for elite athletes and sports coaches.

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).

The demand for dietary supplements containing collagen has been growing for years. The speciality and uniqueness of the dietary supplement (DS) examined in our study is the presence of L-arginine and hyaluronic acid alongside collagen and vitamin C. The individual mechanisms of action and physiological role of these compounds are understood, but they have not yet been tested in the combination and amounts of the dietary supplement used in this study. In this study, we investigated the effectiveness of the DS in elderly patients with musculoskeletal complaints. Somatometric, body composition, physiotherapy and laboratory tests were performed at the beginning and at the end of the study. The two-month study involved 30 people, randomly divided into two groups: a control group (CG) and an experimental group (EG). All subjects consumed 25 ml DS per day and EG members also participated in physiotherapy 3 times a week. Alongside the DS, blood lipid levels changed: LDL decreased, HDL increased, LDL/HDL ratio significantly decreased in both groups. For EG, the results improved more markedly. In 3 items of the body composition test, there was a significant improvement in both groups, which was attributed to the use of the dietary supplement. For the EG, there were significant changes in 5 additional test items, which we attribute to the addition of regular physical activity. Knee and hip joint range of motion (ROM) showed significant improvements in the study group, while in the CG the DS can cause significant improvements in joint range of motion in a passive condition as well.