Excessive training may limit physiological muscle adaptation through chronic oxidative stress and inflammation. Improper diet and overtraining may also disrupt intestinal homeostasis and in consequence enhance inflammation. Altogether, these factors may lead to an imbalance in the gut ecosystem, causing dysregulation of the immune system. Therefore, it seems to be important to optimize the intestinal microbiota composition, which is able to modulate the immune system and reduce oxidative stress. Moreover, the optimal intestinal microbiota composition may have an impact on muscle protein synthesis and mitochondrial biogenesis and function, as well as muscle glycogen storage. Aproperly balanced microbiome may also reduce inflammatory markers and reactive oxygen species production, which may further attenuate macromolecules damage. Consequently, supplementation with probiotics may have some beneficial effect on aerobic and anaerobic performance. The phenomenon of gut-muscle axis should be continuously explored to function maintenance, not only in athletes.

To examine the repeatability and reproducibility of biometry provided by a new anterior-posterior segment spectral-domain optical coherence tomography (SD-OCT) device (Revo NX) and compare it with that provided by a validated optical low-coherence reflectometry (OLCR) biometer (Lenstar LS 900). Hygeia Clinic, Gdańsk, Poland. Prospective evaluation of diagnostic test. The axial length (AL), lens thickness (LT), central corneal thickness (CCT), and anterior chamber depth (ACD) (corneal epithelium to lens) were measured in eyes of volunteers. Two skilled operators obtained 3 measurements in random order with the SD-OCT device. Repeatability was calculated for each observer, while reproducibility was assessed by a change in observer. To compare agreement between the SD-OCT device and OLCR device, the first observer took 3 measurements with both devices. The study evaluated 63 eyes of 63 volunteers. The mean AL measurement (+0.11 mm ± 0.02 [SD]) and mean ACD measurement (0.05 ± 0.04 mm) were significantly higher with the SD-OCT device than with the OLCR device; the CCT measurements did not differ between the devices. A very strong correlation was found for all parameters, while Bland-Altman analysis showed narrow 95% limits of agreement for AL (0.06 to 0.15 mm), ACD (-0.02 to 0.12 mm), LT (-0.23 to 0.17 mm), and CCT (-7.83 to 6.17 μm). The new SD-OCT device provided repeatable and reproducible AL, ACD, LT, and CCT measurements. The results with the SD-OCT device showed strong correlations with those obtained with the OLCR device. However, the AL and ACD measurements of the 2 devices cannot be considered interchangeable.

Parkinson’s disease (PD) is the second most common neurodegenerative disease. To manage motor symptoms not controlled adequately with medication, deep brain stimulation (DBS) is used. PD patients often manifest vitamin D deficiency, which may be connected with a higher risk of falls. We administered a 12-week vitamin D₃ supplementation based on BMI (with higher doses given to patients with higher BMI) to investigate its effects on physical performance and inflammation status in PD patients with DBS. Patients were randomly divided into two groups: treated with vitamin D₃ (VitD, n = 13), and supplemented with vegetable oil as the placebo group (PL, n = 16). Patients underwent functional tests to assess their physical performance three times during this study. The serum 25(OH)D₃ concentration increased to the recommended level of 30 ng/mL in the VitD group, and a significant elevation in vitamin D metabolites in this group was found. We observed significant improvement in the Up and Go and the 6 MWT in the VitD group. In inflammation status, we noticed a trend toward a decrease in the VitD group. To conclude, achieving the optimal serum 25(OH)D₃ concentration is associated with better functional test performance and consequently may have a positive impact on reducing falling risk in PD.

The current study aimed to investigate whether a 12-week Body Mass Index (BMI)-based (the higher the BMI, the higher the dosage) vitamin D₃ administration may affect both the kynurenine pathway (KP) and the inflammatory state in Parkinson’s disease (PD) patients with deep brain stimulation (DBS) and may be useful for developing novel therapeutic targets against PD. Patients were randomly assigned to two groups: supplemented with vitamin D₃ (VitD, n = 15) and treated with vegetable oil (PL, n = 21). Administration lasted for 12 weeks. The isotope dilution method by LC-MS/MS was applied to measure KP and vitamin D metabolites. Serum concentrations of cytokines such as IL-6 and TNF-α were measured using ELISA kits. After administration, the serum concentration of TNF-α decreased in PD patients with DBS. Moreover, in KP: 3-hydroksykynurenine (3-HK) was increased in the PL group, picolinic acid was decreased in the PL group, and kynurenic acid tended to be higher after administration. Furthermore, a negative correlation between 3-HK and 25(OH)D₃ and 24,25(OH)₂D₃ was noticed. Our preliminary results provide further evidence regarding a key link between the KP substances, inflammation status, and metabolites of vitamin D in PD patients with DBS. These findings may reflect the neuroprotective abilities of vitamin D₃ in PD patients with DBS.

It is not fully understood how supplementation with omega-3 fatty acids affects the metabolism of amino acids required for the bioavailability/synthesis of NO, i.e., L-arginine (L-arg), asymmetric dimethylarginine (ADMA), their metabolites, and the L-arg/ADMA ratio and their impact on running economy (RE) in runners. Thus, 26 male amateur endurance runners completed a twelve-week study in which they were divided into two supplemented groups: the OMEGA group (n = 14; 2234 mg and 916 mg of eicosapentaenoic and docosahexaenoic acid daily) or the MCT group (n = 12; 4000 mg of medium-chain triglycerides daily). At the same time, all participants followed an endurance training program. Before and after the 12-week intervention, blood was collected from participants at two time points (at rest and immediately post-exercise) to determine EPA and DHA in red blood cells (RBCs) and plasma levels of L-arg, ADMA, and their metabolites. RBC EPA and DHA significantly increased in the OMEGA group (p < 0.001), which was related to the resting increase in L-arg (p = 0.001) and in the L-arg/ADMA ratio (p = 0.005) with no changes in the MCT group. No differences were found in post-exercise amino acid levels. A total of 12 weeks of omega-3 fatty acid supplementation at a dose of 2234 mg of EPA and 916 mg of DHA daily increased levels of L-arg and the L-arg/ADMA ratio, which indirectly indicates increased bioavailability/NO synthesis. However, these changes were not associated with improved RE in male amateur endurance runners.

Background: Gut microbiota may influence metabolic and inflammatory responses to exercise through the gut–muscle axis, and probiotic supplementation has been proposed to support adaptation and recovery in endurance athletes. However, evidence in trained populations is inconsistent and is confounded by variability in diet, probiotic strains, dose, and intervention duration. We tested whether a multistrain probiotic, administered against a fully standardized diet, would affect exercise performance and inflammatory, metabolic, and muscle-damage responses. Methods: In this randomized, double-blind, placebo-controlled trial, 30 trained male long-distance runners were randomized and 27 completed the study (probiotic [PRO], n = 13; placebo [PLA], n = 14). All participants followed a standardized, normocaloric meal-box diet for four weeks. Aerobic capacity (peak oxygen uptake, VO₂peak; primary outcome) was assessed by an incremental treadmill test and anaerobic performance by a 30 s Wingate test, before (PRE) and after (POST) supplementation. Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), creatine kinase (CK), and lactate (LA) were measured around exercise. Outcomes were analyzed with linear mixed-effects models; the primary estimand was the group × phase interaction. Results: VO₂peak did not differ between groups over time (PLA 55.00 ± 7.60 → 57.33 ± 8.41; PRO 55.40 ± 7.85 → 53.14 ± 5.95 mL·kg⁻¹·min⁻¹; group × phase −3.5 mL·kg⁻¹·min⁻¹, 95% CI −7.0 to −0.1; nominal p = 0.044, not significant after FDR correction, adjusted p = 0.707). No group × phase or group × phase × sampling-time interaction was significant for IL-6, TNF-α, LA, or CK (all interaction p > 0.15), indicating that supplementation did not modify the exercise-induced response of any biomarker; exercise itself robustly increased IL-6, TNF-α, and LA in both groups (p < 0.001). Conclusions: In trained male endurance runners consuming a standardized diet, four weeks of multistrain probiotic supplementation did not significantly affect aerobic or anaerobic performance, LA response, muscle-damage markers, or circulating inflammatory cytokines compared with placebo. Adequately powered trials with prespecified primary endpoints and direct microbiome assessment are needed.