The Effect of Glutamine in Modulating Exertional Heat Stress Response of Intestinal Cells in Trained and Untrained Runners

Glutamine is the preferred substrate of intestinal cells and is required for the protection of intestinal cells integrity, helping to prevent exercise-induced endotoxin leakage from the intestine during stressful conditions. Increased endotoxins in the blood circulation (also known as endotoxaemia) has been shown to trigger systemic inflammation which is implicated in exertional heat stroke. This study examined firstly whether orally administered glutamine helps to reduce intestinal injury following an acute high intensity exercise session in hot conditions and secondly whether there is a different outcome according to fitness levels in runners. A randomized, double-blinded crossover study design was utilized. Twelve runners unacclimatised to heat, divided into trained [T; n=6; maximal oxygen uptake (VO2max) = 61.2 ± 1.0 ml∙kg-1∙min-1] and untrained (UT; n=6; VO2max = 51.0 ± 0.7 ml∙kg-1∙min-1) groups, ingested either a placebo or glutamine dipeptide supplement (L-alanyl-L-glutamine; 0.2 g/kg bodyweight/day) for 5 consecutive days before running at 70%VO2max in a climate chamber (30°C, 40% relative humidity) for 1 hour. Cardiac output, stroke volume, heart rates, sweat loss, percent dehydration, rectal and skin surface temperatures were measured. Venous blood samples at baseline, immediately after completion of run and 1-hour post run were analysed for endotoxins and intestinal fatty acid binding proteins (I-FABP) as markers of intestinal injury. Intestinal permeability was measured at pre and post exercise using dual sugar probes (L-R; lactulose and rhamnose). No significant difference was observed in all responses for training status. L-R ratios remained unchanged with or without glutamine. However, a significant main effect for time and treatment was observed for plasma I-FABP (

CREATINE SUPPLEMENTATION AND SWIM PERFORMANCE: A BRIEF REVIEW

Nutritional supplements are popular among athletes participating in a wide variety of sports. Creatine is one of the most commonly used dietary supplements, as it has been shown to be beneficial in improving performance during repeated bouts of high-intensity anaerobic activity. This review examines the specific effects of creatine supplementation on swimming performance, and considers the effects of creatine supplementation on various measures of power development in this population. Research performed on the effect of creatine supplementation on swimming performance indicates that whilst creatine supplementation is ineffective in improving performance during a single sprint swim, dietary creatine supplementation may benefit repeated interval swim set performance. Considering the relationship between sprint swimming performance and measurements of power, the effect of creatine supplementation on power development in swimmers has also been examined. When measured on a swim bench ergometer, power development does show some improvement following a creatine supplementation regime. How this improvement in power output transfers to performance in the pool is uncertain. Although some evidence exists to suggest a gender effect on the performance improvements seen in swimmers following creatine supplementation, the majority of research indicates that male and female swimmers respond equally to supplementation. A major limitation to previous research is the lack of consideration given to the possible stroke dependant effect of creatine supplementation on swimming performance. The majority of the research conducted to date has involved examination of the freestyle swimming stroke only. The potential for performance improvements in the breaststroke and butterfly swimming strokes is discussed, with regards to the biomechanical differences and differences in efficiency between these strokes and freestyl

Low-carbohydrate diets for type 1 diabetes mellitus: A systematic review

<div><p>Type 1 diabetes is an autoimmune condition characterised by pancreatic beta cell destruction and absolute insulin deficiency. The strongest predictor of diabetes complications is glycaemic control and achieving HbA1c ≤ 7.0% is the primary management target. However, standard treatment appears to be lacking and adjunctive strategies require consideration. A systematic review was conducted to examine the effect of low-carbohydrate diets on type 1 diabetes management. Four databases were searched from inception until 28 March 2017: MEDLINE; CINAHL; Cochrane Library; and EMBASE. All primary studies containing a methods section (excluding cross-sectional) were included. Reports had to quantitatively measure the effect(s) of a dietary intervention or observed intake over at least two weeks where carbohydrate is below 45% total energy in adults and/or children with type 1 diabetes. The primary outcome was HbA1c and secondary outcomes were severe hypoglycaemia, total daily insulin, BMI, quality of life and mean daily glucose. Seventy-nine full-text articles were assessed for eligibility and nine were included (two randomised controlled trials, four pre-post interventions, two case-series, one case-report). Eight studies reported a mean change in HbA1c with a low-carbohydrate diet. Of these, four reported a non-significant change (P ≥ 0.05) and three reported statistically significant reductions (P < 0.05). Two studies reported severe hypoglycaemia, five reported total insulin, three reported BMI, and one reported blood glucose. Due to the significant heterogeneity of included studies, an overall effect could not be determined. This review presents all available evidence on low-carbohydrate diets for type 1 diabetes and suggests an urgent need for more primary studies.</p></div

Compression garments and recovery from eccentric exercise: A 31P-MRS study

The low oxidative demand and muscular adaptations accompanying eccentric exercise hold benefits for both healthy and clinical populations. Compression garments have been suggested to reduce muscle damage and maintain muscle function. This study investigated whether compression garments could benefit metabolic recovery from eccentric exercise. Following 30-min of downhill walking participants wore compression garments on one leg (COMP), the other leg was used as an internal, untreated control (CONT). The muscle metabolites phosphomonoester (PME), phosphodiester (PDE), phosphocreatine (PCr), inorganic phosphate (Pi) and adenosine triphosphate (ATP) were evaluated at baseline, 1-h and 48-h after eccentric exercise using 31P-magnetic resonance spectroscopy. Subjective reports of muscle soreness were recorded at all time points. The pressure of the garment against the thigh was assessed at 1-h and 48-h following exercise. There was a significant increase in perceived muscle soreness from baseline in both the control (CONT) and compression (COMP) leg at 1-h and 48-h following eccentric exercise (p < 0.05). Relative to baseline, both CONT and COMP showed reduced pH at 1-h (p < 0.05). There was no difference between CONT and COMP pH at 1-h. COMP legs exhibited significantly (p < 0.05) elevated skeletal muscle PDE 1-h following exercise. There was no significant change in PCr/Pi, Mg2+ or PME at any time point or between CONT and COMP legs. Eccentric exercise causes disruption of pH control in skeletal muscle but does not cause disruption to cellular control of free energy. Compression garments may alter potential indices of the repair processes accompanying structural damage to the skeletal muscle following eccentric exercise allowing a faster cellular repai

Effect of intervention and comparator diets on type 1 diabetes management outcomes (primary and secondary).

<p>Effect of intervention and comparator diets on type 1 diabetes management outcomes (primary and secondary).</p

Summary of findings table (GRADE) for primary outcome (HbA1c).

<p>Summary of findings table (GRADE) for primary outcome (HbA1c).</p

Characteristics of included studies.

<p>Characteristics of included studies.</p

PRISMA flow chart.

<p>PRISMA flow chart.</p

Associations between CD36 gene polymorphisms and metabolic response to a short-term endurance training program in a young-adult population

Purpose: Recent studies have shown that CD36 gene variants are associated with an increased prevalence of chronic disease. Although a genetic component to trainability has been proven, no data is available on the influence of CD36 on training response. Methods: Two single nucleotide polymorphisms (SNPs) (rs1527479 and rs1984112) were assessed for associations with whole-body substrate oxidation, response to a 75g dextrose oral glucose tolerance test (OGTT), fasting plasma lipids and CVD risk factors in a young healthy cohort, both using cross-sectional analysis and following a 4-week endurance exercise training program. Genotyping was performed using real-time polymerase chain reaction (PCR). Results: Cross-sectional data was collected in 34 individuals (22.7 ± 3.5y), with 17 completing the training program. At baseline, TT SNP carriers at rs1527479 and wild-type (WT) GG carriers at rs1984112 were associated with significantly greater whole-body rate of fat oxidation (Fatox) during submaximal exercise (PThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author