Analysis of the Effects of Dietary Pattern on the Oral Microbiome of Elite Endurance Athletes

Although the oral microbiota is known to play a crucial role in human health, there are few studies of diet x oral microbiota interactions, and none in elite athletes who may manipulate their intakes of macronutrients to achieve different metabolic adaptations in pursuit of optimal endurance performance. The aim of this study was to investigate the shifts in the oral microbiome of elite male endurance race walkers from Europe, Asia, the Americas and Australia, in response to one of three dietary patterns often used by athletes during a period of intensified training: a High Carbohydrate (HCHO; = 9; with 60% energy intake from carbohydrates; ~8.5 g kg day carbohydrate, ~2.1 g kg day protein, 1.2 g kg day fat) diet, a Periodised Carbohydrate (PCHO; = 10; same macronutrient composition as HCHO, but the intake of carbohydrates is different across the day and throughout the week to support training sessions with high or low carbohydrate availability) diet or a ketogenic Low Carbohydrate High Fat (LCHF; = 10; 0.5 g kg day carbohydrate; 78% energy as fat; 2.1 g kg day protein) diet. Saliva samples were collected both before (Baseline; BL) and after the three-week period (Post treatment; PT) and the oral microbiota profiles for each athlete were produced by 16S rRNA gene amplicon sequencing. Principal coordinates analysis of the oral microbiota profiles based on the weighted UniFrac distance measure did not reveal any specific clustering with respect to diet or athlete ethnic origin, either at baseline (BL) or following the diet-training period. However, discriminant analyses of the oral microbiota profiles by Linear Discriminant Analysis (LDA) Effect Size (LEfSe) and sparse Partial Least Squares Discriminant Analysis (sPLS-DA) did reveal changes in the relative abundance of specific bacterial taxa, and, particularly, when comparing the microbiota profiles following consumption of the carbohydrate-based diets with the LCHF diet. These analyses showed that following consumption of the LCHF diet the relative abundances of and spp. were decreased, and the relative abundance of spp. was increased. Such findings suggest that diet, and, in particular, the LCHF diet can induce changes in the oral microbiota of elite endurance walkers

Recovering 6D Object Pose: A Review and Multi-modal Analysis

A large number of studies analyse object detection and pose estimation at visual level in 2D, discussing the effects of challenges such as occlusion, clutter, texture, etc., on the performances of the methods, which work in the context of RGB modality. Interpreting the depth data, the study in this paper presents thorough multi-modal analyses. It discusses the above-mentioned challenges for full 6D object pose estimation in RGB-D images comparing the performances of several 6D detectors in order to answer the following questions: What is the current position of the computer vision community for maintaining "automation" in robotic manipulation? What next steps should the community take for improving "autonomy" in robotics while handling objects? Our findings include: (i) reasonably accurate results are obtained on textured-objects at varying viewpoints with cluttered backgrounds. (ii) Heavy existence of occlusion and clutter severely affects the detectors, and similar-looking distractors is the biggest challenge in recovering instances' 6D. (iii) Template-based methods and random forest-based learning algorithms underlie object detection and 6D pose estimation. Recent paradigm is to learn deep discriminative feature representations and to adopt CNNs taking RGB images as input. (iv) Depending on the availability of large-scale 6D annotated depth datasets, feature representations can be learnt on these datasets, and then the learnt representations can be customized for the 6D problem

Nonparametric estimation of infinitely divisible distributions based on variational analysis on measures

The paper develops new methods of non-parametric estimation a compound Poisson distribution. Such a problem arise, in particular, in the inference of a Levy process recorded at equidistant time intervals. Our key estimator is based on series decomposition of functionals of a measure and relies on the steepest descent technique recently developed in variational analysis of measures. Simulation studies demonstrate applicability domain of our methods and how they positively compare and complement the existing techniques. They are particularly suited for discrete compounding distributions, not necessarily concentrated on a grid nor on the positive or negative semi-axis. They also give good results for continuous distributions provided an appropriate smoothing is used for the obtained atomic measure

Muscle PGC-1α is required for long-term systemic and local adaptations to a ketogenic diet in mice

Low-carbohydrate/high-fat (LCHF) diets are increasingly popular dietary interventions for body weight control and as treatment for different pathological conditions. However, the mechanisms of action are still poorly understood, in particular, in long-term administration. Besides liver, brain, and heart, skeletal muscle is one of the major organs involved in the regulation of physiological and pathophysiological ketosis. We assessed the role of the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) in skeletal muscle of male wild-type control and PGC-1α muscle-specific knockout mice upon 12 wk of LCHF diet feeding. Interestingly, LCHF diet administration increased oxygen consumption in a muscle PGC-1α-dependent manner, concomitant with a blunted transcriptional induction of genes involved in fatty acid oxidation and impairment in exercise performance. These data reveal a new role for muscle PGC-1α in regulating the physiological adaptation to long-term LCHF diet administration

Twitterati and Paperati – evidence versus popular opinion in science communication

Science communication has traditionally been the remit of peer-reviewed journals with information being shared, almost exclusively, within the academic community. For those working at the coalface the limited scope of this traditional discourse in terms of access and consumption by key stakeholders (eg, coaches, National Governing Bodies of sport, sport scientists) is of concern. In fact, traditional peer-reviewed publication does not seem to be the most effective mechanism for scientists to engage with the public and to disseminate knowledge

Effects of a 15-Day Low Carbohydrate, High Fat Diet in Resistance Trained Males

This study examined the effects of a 15-day isocaloric low carbohydrate (,25% E), high-fat (.50% E) (LCHF) diet on physiological and metabolic alterations in resistance-trained (RT) men. College-aged RT men (n = 11) completed 4 V_ O2max tests using treadmill every 5 days during the 15-day trial. Blood was drawn intravenously pre-exercise across each experimental trial for insulin, cortisol, and glucose. Pulmonary data were collected and substrate oxidation (OXI) was calculated during exercise. Body mass decreased (p , 0.04) with no further changes in anthropometric measures. Time to exhaustion was not affected across each day. Insulin dropped below baseline values (p , 0.0005). Cortisol increased from baseline to day 5 (p , 0.004) but returned back to near baseline at day 10, whereas glucose remained within normal range throughout the duration of the study. Carbohydrate (CHO) OXI dropped (p , 0.001) from baseline to day 5, and fat OXI increased from baseline to day 5 (p , 0.0001). Heart rate decreased from baseline to day 5 (p , 0.001) and again from day 10 to 15 (p , 0.02). Oxygen uptake (V_ O2) decreased from day 5 to 10 (p , 0.0001). A nonketo LCHF diet appears to favor RT men by altering metabolic markers without decrements in aerobic performance and be a potential diet intervention used by coaches. However, the reported cardiorespiratory responses should be interpreted reasonably because of the possibility the subjects running economy improved over experimental trials

Endogenous glucose production and gluconeogenesis during exercise in athletes on either a low-carbohydrate or mixed diet

INTRODUCTION. The LCHF diet produces major changes in whole-body substrate metabolism and energy stores such as reduced muscle and liver glycogen content, increased rates of fat oxidation and decreased rates of carbohydrate (CHO) oxidation. Despite reduced CHO availability, the rate of CHO oxidation that can be sustained during exercise in LCHF athletes is surprisingly high. The most probable source of this glucose is via the process of gluconeogenesis (GNG). However, endogenous glucose production (EGP) and GNG has not been studied during exercise in athletes on a LCHF diet. Therefore, the aim of this study was to determine if there are differences in EGP, GNG and glycogenolysis (GLY) during exercise in endurance-trained athletes who habitually eat either a mixed or LCHF diet. METHODS. Fourteen (7 LCHF, 7 Mix) endurance-trained male cyclists (VO₂max 61 ± 5 ml/kg/min LCHF; 6 3 ± 8 ml/kg/min Mix), matched for age (36 ± 6 y LCHF; 32 ± 5 y Mix), body composition (BMI 23.6 ± 1.8 LCHF; 23.4 ± 2.0 Mix) and relative peak power output (4.8 ± 0.4 W/kg LCHF; 5.0 ± 0.4 W/kg Mix), were recruited. Diets were analysed using the Automated Self-Administered 24-hour Recall (ASA24) analysis software. Participants cycled for 2 h at 55% of peak power output during which EGP was measured by infusion of [6,6- ²H₂ ]glucose, and fractional gluconeogenesis was measured by ingestion of ²H₂O. Blood samples were collected at regular intervals for isotope enrichment analysis. R ESULTS. Rates of GNG were similar during exercise in both the LCHF and mixed diet groups (2.8 ± 0.4 mg/kg/min LCHF; 2.5 ± 0.3 mg/kg/min Mix). The rates of GLY during exercise were significantly higher in the mixed diet group than the LCHF group (3.2 ± 0.7 mg/kg/min LCHF; 5.3 ± 0.9 mg/kg/min Mix) which resulted in significantly higher rates of EGP in the mixed diet group (6.0 ± 0.9 mg/kg/min LCHF; 7.8 ± 1.1 mg/kg/min Mix). There were significant differences in the mean fat oxidation rates (1.2 ± 0.2 g/min LCHF; 0.5 ± 0.2 g/min Mix) and CHO oxidation rates (1.3 ± 0.5 g/min LCHF; 3.1 ± 0.5 g/min Mix). Blood beta-hydroxbutyrate (βHB) concentrations were significantly higher in the LCHF group than in the mixed diet group throughout exercise but there were no differences in plasma glucose, plasma lactate, serum insulin or serum FFA concentrations. The diets of the two groups differed only in fat and CHO intake (%Protein / %Fat / %CHO: 21/72/7 LCHF; 16/33/51 Mix). DISCUSSION. Rates of fat oxidation and CHO oxidation were not associated with the rates of GNG. Apart from βHB, the precursor, substrate and insulin concentrations were remarkably similar in both groups and may have influenced GNG similarly in both groups. We conclude that rates of GNG are relatively stable across a broad range of habitual diets that can significantly alter substrate utilisation, and that dietary CHO modulates the rates of EGP via alterations in rates of GLY, both at rest and during exercise