Superior bioavailability of the calcium salt form of ß-hydroxy-ß-methylbutyrate compared with the free acid form.

We investigated the bioavailability of the calcium salt (HMB-Ca) and the free acid (HMB-FA) forms of ß-hydroxy-ß-methylbutyrate (HMB). Sixteen young individuals received the following treatments on three different occasions in a counterbalanced crossover fashion: (1) HMB-FA in clear capsules; (2) HMB-Ca in gelatine capsules; (3) HMB-Ca dissolved in water. All treatments provided 1 g of HMB. Blood samples were taken before and on multiple time points following ingestion. The following parameters were calculated: peak plasma (Cmax), time to peak (Tmax), slope of HMB appearance in blood, area under the curve (AUC), half-life time (t1/2) and relative bioavailability (HMB-Ca in water set as reference). All treatments led to rapid and large increases in plasma HMB. HMB-Ca in capsules and in water showed similar plasma HMB values across time (p = 0.438). HMB-FA resulted in lower concentrations vs. the other treatments (both p < 0.001). AUC (HMB-Ca in capsules: 50,078 ± 10,507; HMB-Ca in water: 47,871 ± 10,783; HMB-FA: 29,130 ± 12,946 µmol L-1 × 720 min), Cmax (HMB-Ca in capsules: 229.2 ± 65.9; HMB-Ca in water: 249.7 ± 49.7; HMB-FA: 139.1 ± 67.2 µmol L-1) and relative bioavailability (HMB-Ca in capsules: 104.8 ± 14.9%; HMB-FA: 61.5 ± 17.0%) were lower in HMB-FA vs. HMB-Ca (all p < 0.001). HMB-Ca in water resulted in the fastest Tmax (43 ± 22 min) compared to HMB-Ca in capsules (79 ± 40 min) and HMB-FA (78 ± 21 min) (all p < 0.05), while t1/2 was similar between treatments. To conclude, HMB-Ca exhibited superior bioavailability compared to HMB-FA, with HMB-Ca in water showing faster absorption. Elimination kinetics were similar across all forms, suggesting that the pharmaceutical form of HMB affects the absorption rates, but not its distribution or elimination.

Potential of Creatine in Glucose Management and Diabetes.

Creatine is one of the most popular supplements worldwide, and it is frequently used by both athletic and non-athletic populations to improve power, strength, muscle mass and performance. A growing body of evidence has been identified potential therapeutic effects of creatine in a wide variety of clinical conditions, such as cancer, muscle dystrophy and neurodegenerative disorders. Evidence has suggested that creatine supplementation alone, and mainly in combination with exercise training, may improve glucose metabolism in health individuals and insulin-resistant individuals, such as in those with type 2 diabetes mellitus. Creatine itself may stimulate insulin secretion in vitro, improve muscle glycogen stores and ameliorate hyperglycemia in animals. In addition, exercise induces numerous metabolic benefits, including increases in insulin-independent muscle glucose uptake and insulin sensitivity. It has been speculated that creatine supplementation combined with exercise training could result in additional improvements in glucose metabolism when compared with each intervention separately. The possible mechanism underlying the effects of combined exercise and creatine supplementation is an enhanced glucose transport into muscle cell by type 4 glucose transporter (GLUT-4) translocation to sarcolemma. Although preliminary findings from small-scale trials involving patients with type 2 diabetes mellitus are promising, the efficacy of creatine for improving glycemic control is yet to be confirmed. In this review, we aim to explore the possible therapeutic role of creatine supplementation on glucose management and as a potential anti-diabetic intervention, summarizing the current knowledge and highlighting the research gaps.

Land-use impacts on benthic macroinvertebrate assemblages in pampean streams (Argentina).

In recent decades agriculture has intensified in the Argentine Pampa, and pesticide application has also increased. Livestock fields, although being progressively replaced by crops, are still commonly interspersed with crop fields. The objective of the present work is to assess the effects of land use on the benthic invertebrate assemblages of streams in the main Argentine agricultural region. Two areas were sampled during the 2011/12 growing season (November-March): Arrecifes, a homogeneous intensively cultivated area, and La Plata, a heterogeneous area of mixed livestock pasture, cropland and biological reserve. Nutrient concentrations in water were significantly higher in the streams surrounded by cropland. Measured pesticides in stream sediments were those most commonly used in crop production: chlorpyrifos, cypermethrin, lambda-cyhalothrin, endosulfan and its degradation product endosulfan sulfate. Detection frequency and pesticide concentrations were generally higher in streams surrounded by cropland than in streams surrounded by pasture or reserve. Macroinvertebrate assemblages were significantly different in streams with different land uses. Palaemonidae (Decapoda) and Caenidae (Ephemeroptera) were the taxa best represented in the reserve. Hyalellidae (Amphipoda) and Hirudinea were dominant at the streams surrounded by livestock fields. Within the streams surrounded by croplands, Oligochaeta and Hirudinea were best represented in La Plata while Chironomidae, Gastropoda and Oligochaeta were dominant at Arrecifes. Present evidence suggests that agrochemical applications contribute, in combination with other environmental variables, to the observed differences in macroinvertebrate assemblages in streams of different land use.

Omega-3 Fatty Acid Supplementation Improves Endothelial Function in Primary Antiphospholipid Syndrome: A Small-Scale Randomized Double-Blind Placebo-Controlled Trial.

Endothelial cells are thought to play a central role in the pathogenesis of antiphospholipid syndrome (APS). Omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation has been shown to improve endothelial function in a number of diseases; thus, it could be of high clinical relevance in APS. The aim of this study was to evaluate the efficacy of n-3 PUFA supplementation on endothelial function (primary outcome) of patients with primary APS (PAPS). A 16-week randomized clinical trial was conducted with 22 adult women with PAPS. Patients were randomly assigned (1:1) to receive placebo (PL, n = 11) or n-3 PUFA (ω-3, n = 11) supplementation. Before (pre) and after (post) 16 weeks of the intervention, patients were assessed for endothelial function (peripheral artery tonometry) (primary outcome). Patients were also assessed for systemic markers of endothelial cell activation, inflammatory markers, dietary intake, international normalized ratio (INR), and adverse effects. At post, ω-3 group presented significant increases in endothelial function estimates reactive hyperemia index (RHI) and logarithmic transformation of RHI (LnRHI) when compared with PL (+13 vs. -12%, p = 0.06, ES = 0.9; and +23 vs. -22%, p = 0.02, ES = 1.0). No changes were observed for e-selectin, vascular adhesion molecule-1, and fibrinogen levels (p > 0.05). In addition, ω-3 group showed decreased circulating levels of interleukin-10 (-4 vs. +45%, p = 0.04, ES = -0.9) and tumor necrosis factor (-13 vs. +0.3%, p = 0.04, ES = -0.95) and a tendency toward a lower intercellular adhesion molecule-1 response (+3 vs. +48%, p = 0.1, ES = -0.7) at post when compared with PL. No changes in dietary intake, INR, or self-reported adverse effects were observed. In conclusion, 16 weeks of n-3 PUFA supplementation improved endothelial function in patients with well-controlled PAPS. These results support a role of n-3 PUFA supplementation as an adjuvant therapy in APS. Registered at http://ClinicalTrials.gov as NCT01956188.

Aquatic macroinvertebrate assemblages are affected by insecticide applications on the Argentine Pampas.

Agriculture intensification in Argentina has increased agrochemicals consumption in the last decades and might represent an environmental risk for adjacent water bodies. The objective of the present work was to assess the effect of land use on water quality and invertebrate assemblages in the Argentine Pampas streams. Eight streams were sampled on 4 occasions during the 2013/14 growing season. Three streams are located within a biosphere reserve, two drain basins with extensive livestock fields, and three run through intensively cultivated plots; one of them contained a 30m wide uncultivated grass-covered strip between the crop and the stream. Macroinvertebrates were sampled from emergent vegetation by means of a D-net with a 500µm pore size, and 30cm diameter. Higher nutrient concentrations were measured in the agricultural streams. Endosulfan was measured in sediments of the agricultural streams, concentrations being significantly lower in the stream with the buffer strip. Invertebrate assemblages in the cropped streams were significantly different from those in the livestock and reserve streams, those in the latter not being different from each other. Ampullaridae (Pomacea canaliculata) and Planorbidae (Biomophalaria peregrina) were the taxa best represented in the agricultural streams. Hyalellidae (Hyalella curvispina), Zygoptera and Planorbidae (B. peregrina) were the taxa best represented in the reserve and livestock streams. Present evidence suggests that the observed differences in the invertebrate composition in the agricultural streams were related with the impact of agrochemicals and that buffer strips represent a useful attenuation practice. Cattle breeding on natural pastures represented a land use with low impact on the invertebrate assemblages.

Effect of age, diet, and tissue type on PCr response to creatine supplementation.

Creatine/phosphorylcreatine (PCr) responses to creatine supplementation may be modulated by age, diet, and tissue, but studies assessing this possibility are lacking. Therefore we aimed to determine whether PCr responses vary as a function of age, diet, and tissue. Fifteen children, 17 omnivorous and 14 vegetarian adults, and 18 elderly individuals ("elderly") participated in this study. Participants were given placebo and subsequently creatine (0.3 g·kg-1·day-1) for 7 days in a single-blind fashion. PCr was measured through phosphorus magnetic resonance spectroscopy (31P-MRS) in muscle and brain. Creatine supplementation increased muscle PCr in children (P < 0.0003) and elderly (P < 0.001), whereas the increase in omnivores did not reach statistically significant difference (P = 0.3348). Elderly had greater PCr increases than children and omnivores (P < 0.0001 for both), whereas children experienced greater PCr increases than omnivores (P = 0.0022). In relation to diet, vegetarians (P < 0.0001), but not omnivores, had significant increases in muscle PCr content. Brain PCr content was not affected by creatine supplementation in any group, and delta changes in brain PCr (-0.7 to +3.9%) were inferior to those in muscle PCr content (+10.3 to +27.6%; P < 0.0001 for all comparisons). PCr responses to a standardized creatine protocol (0.3 g·kg-1·day-1 for 7 days) may be affected by age, diet, and tissue. Whereas creatine supplementation was able to increase muscle PCr in all groups, although to different extents, brain PCr was shown to be unresponsive overall. These findings demonstrate the need to tailor creatine protocols to optimize creatine/PCr accumulation both in muscle and in brain, enabling a better appreciation of the pleiotropic properties of creatine.NEW & NOTEWORTHY A standardized creatine supplementation protocol (0.3 g·kg-1·day-1 for 7 days) effectively increased muscle, but not brain, phosphorylcreatine. Older participants responded better than younger participants whereas vegetarians responded better than omnivores. Responses to supplementation are thus dependent on age, tissue, and diet. This suggests that a single "universal" protocol, originally designed for increasing muscle creatine in young individuals, may lead to heterogeneous muscle responses in different populations or even no responses in tissues other than skeletal muscle.

Land use effect on invertebrate assemblages in Pampasic streams (Buenos Aires, Argentina).

Agriculture and livestock may contribute to water quality degradation in adjacent waterbodies and produce changes in the resident invertebrate composition. The objective of the present study was to assess land use effects on the stream invertebrate assemblages in rural areas of the Argentine Pampa. The four sampling events were performed at six sites in four streams of the Pampa plain; two streams were sampled inside a biosphere reserve, and another one was surrounded by extensive livestock fields. The fourth stream was sampled at three sites; the upstream site was adjacent to agricultural plots, the following site was adjacent to an intensive livestock plot and the downstream site was adjacent to extensive breeding cattle plots. Higher pesticide concentrations were found at the site adjacent to agricultural plots and higher nutrient concentrations at the sites adjacent to agricultural and intensive breeding cattle plots. The invertebrate fauna were also different at these sites. Multivariate analysis showed a relationship between nutrient concentrations and taxonomic composition. Amphipoda (Hyalella curvispina) was the dominant group in the reserve and extensive breeding cattle sites, but was not present in the agricultural site. Also, Chironomidae were absent from the agricultural site while present at other sites. Gasteropoda (Biomphalaria peregrina), Zygoptera, and Hirudinea were dominant at the most impacted agricultural and intensive breeding cattle sites.

Physical (in)activity and its influence on disease-related features, physical capacity, and health-related quality of life in a cohort of chronic juvenile dermatomyositis patients.

OBJECTIVES: To objectively measure physical activity levels in a cohort of juvenile dermatomyositis (JDM) patients; to compare physical capacity and health-related quality of life in JDM patients and their healthy controls (CTRL) matched by physical activity levels; and to associate physical activity variables with disease-related parameters, physical capacity, and health-related quality of life. METHODS: This was a cross-sectional study in which 19 JDM patients and 19 CTRL matched by physical activity levels, age, sex, and body mass index were compared. Physical activity was objectively measured using accelerometers. RESULTS: In our cohort, only one of the 19 JDM patients (5%) achieved the minimum recommended moderate-to-vigorous physical activity levels (MVPA) (i.e., minimum of 60min/day). JDM showed lower aerobic condition (e.g., VO2peak), muscle function (e.g., timed-stands test), and health-related quality of life in comparison to CTRL (p < 0.05). Sedentary time was positively correlated with disease duration (r = 0.649; p = 0.003), and negatively with VO2peak (r = -0.459; p = 0.048). Moreover, MVPA was negatively associated with disease duration (r = -0.509; p = 0.026), and positively associated with VO2peak (r = 0.797; p < 0.001), and current use of corticoid (r = 0.748; p < 0.001). CONCLUSION: Physical capacity and health-related quality of life were reduced in JDM patients when compared with CTRL matched by physical activity levels, suggesting that the disease itself and/or glucocorticoid use may adversely affect overall health in JDM, despite an apparently well-controlled disease. Physical (in)activity correlated with important disease-related and physical capacity parameters, suggesting that sedentary lifestyle may be an important, but preventable, factor associated with poor overall health in JDM.

Efficacy and safety of creatine supplementation in juvenile dermatomyositis: A randomized, double-blind, placebo-controlled crossover trial.

INTRODUCTION: It has been suggested that creatine supplementation is safe and effective for treating idiopathic inflammatory myopathies, but no pediatric study has been conducted to date. The objective of this study was to examine the efficacy and safety of creatine supplementation in juvenile dermatomyositis (JDM) patients. METHODS: In this study, JDM patients received placebo or creatine supplementation (0.1 g/kg/day) in a randomized, crossover, double-blind design. Subjects were assessed at baseline and after 12 weeks. The primary outcome was muscle function. Secondary outcomes included body composition, aerobic conditioning, health-related quality of life, and muscle phosphocreatine (PCr) content. Safety was assessed by laboratory parameters and kidney function measurements. RESULTS: Creatine supplementation did not affect muscle function, intramuscular PCr content, or any other secondary outcome. Kidney function was not affected, and no side effects were reported. CONCLUSIONS: Twelve weeks of creatine supplementation in JDM patients were well-tolerated and free of adverse effects, but treatment did not affect muscle function, intramuscular PCr, or any other parameter.

Can creatine supplementation form carcinogenic heterocyclic amines in humans?

There is a long-standing concern that creatine supplementation could be associated with cancer, possibly by facilitating the formation of carcinogenic heterocyclic amines (HCAs). This study provides compelling evidence that both low and high doses of creatine supplementation, given either acutely or chronically, does not cause a significant increase in HCA formation. HCAs detection was unrelated to creatine supplementation. Diet was likely to be the main factor responsible for HCAs formation after either placebo (n = 6) or creatine supplementation (n = 3). These results directly challenge the recently suggested biological plausibility for the association between creatine use and risk of testicular germ cell cancer. Creatine supplementation has been associated with increased cancer risk. In fact, there is evidence indicating that creatine and/or creatinine are important precursors of carcinogenic heterocyclic amines (HCAs). The present study aimed to investigate the acute and chronic effects of low- and high-dose creatine supplementation on the production of HCAs in healthy humans (i.e. 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx), 2-amino-(1,6-dimethylfuro[3,2-e]imidazo[4,5-b])pyridine (IFP) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx)). This was a non-counterbalanced single-blind crossover study divided into two phases, in which low- and high-dose creatine protocols were tested. After acute (1 day) and chronic supplementation (30 days), the HCAs PhIP, 8-MeIQx, IFP and 4,8-DiMeIQx were assessed through a newly developed HPLC-MS/MS method. Dietary HCA intake and blood and urinary creatinine were also evaluated. Out of 576 assessments performed (from 149 urine samples), only nine (3 from creatine and 6 from placebo) showed quantifiable levels of HCAs (8-MeIQx: n = 3; 4,8-DiMeIQx: n = 2; PhIP: n = 4). Individual analyses revealed that diet rather than creatine supplementation was the main responsible factor for HCA formation in these cases. This study provides compelling evidence that both low and high doses of creatine supplementation, given either acutely or chronically, did not cause increases in the carcinogenic HCAs PhIP, 8-MeIQx, IFP and 4,8-DiMeIQx in healthy subjects. These findings challenge the long-existing notion that creatine supplementation could potentially increase the risk of cancer by stimulating the formation of these mutagens.

Acute Toxicity of Endosulfan to the Non-target Organisms Hyalella curvispina and Cnesterodon decemmaculatus.

Pesticide consumption in Argentina has steadily increased over the last two decades, while one of these compounds, namely endosulfan, is commonly found in environmental samples. Also the fish Cnesterodon decemmaculatus and the amphipod Hyalella curvispina are widely distributed in agricultural areas of southern South America. The aim of the present contribution was therefore to determine the acute toxicity of endosulfan to both organisms, and compare it with species sensitivity distributions (SSD) and measured field concentrations. The 48 h-LC50 (with 95 % confidence limits) were 1.8 (1.6-2.1) µg/L for C. decemmaculatus and 16.4 (15.1-17.7) µg/L for H. curvispina. C. decemmaculatus was more sensitive than 74 % of fish based on the SSD. Endosulfan concentrations in stream water reported in the literature were often higher than the C. decemmaculatus LC50. It may hence be concluded that C. decemmaculatus is a suitable sentinel organism for ecotoxicological risk assessment in South America.

Effects of beta-alanine supplementation on brain homocarnosine/carnosine signal and cognitive function: an exploratory study.

OBJECTIVES: Two independent studies were conducted to examine the effects of 28 d of beta-alanine supplementation at 6.4 g d(-1) on brain homocarnosine/carnosine signal in omnivores and vegetarians (Study 1) and on cognitive function before and after exercise in trained cyclists (Study 2). METHODS: In Study 1, seven healthy vegetarians (3 women and 4 men) and seven age- and sex-matched omnivores undertook a brain 1H-MRS exam at baseline and after beta-alanine supplementation. In study 2, nineteen trained male cyclists completed four 20-Km cycling time trials (two pre supplementation and two post supplementation), with a battery of cognitive function tests (Stroop test, Sternberg paradigm, Rapid Visual Information Processing task) being performed before and after exercise on each occasion. RESULTS: In Study 1, there were no within-group effects of beta-alanine supplementation on brain homocarnosine/carnosine signal in either vegetarians (p = 0.99) or omnivores (p = 0.27); nor was there any effect when data from both groups were pooled (p = 0.19). Similarly, there was no group by time interaction for brain homocarnosine/carnosine signal (p = 0.27). In study 2, exercise improved cognitive function across all tests (P < 0.05), although there was no effect (P>0.05) of beta-alanine supplementation on response times or accuracy for the Stroop test, Sternberg paradigm or RVIP task at rest or after exercise. CONCLUSION: 28 d of beta-alanine supplementation at 6.4 g d(-1) appeared not to influence brain homocarnosine/carnosine signal in either omnivores or vegetarians; nor did it influence cognitive function before or after exercise in trained cyclists.

Acute toxicity of chlorpyrifos to the non-target organism Cnesterodon decemmaculatus.

Chlorpyrifos is the most used insecticide in Argentina. Cnesterodon decemmaculatus is a widely distributed, endemic fish from Neotropical America. It attains high densities in the shallow water assemblages of Argentina and Brazil. The aim of this study was to assess the acute toxicity of chlorpyrifos to C. decemmaculatus. The mean 96-h LC50 of three independent determinations was 105.3 (± 3.1) µg/L. Sublethal effects were observed. Swimming behavioral changes at each chlorpyrifos exposure concentration were reported. C. decemmaculatus represents a good model for ecotoxicological risk assessment.

The liposuction-induced effects on adiponectin and selected cytokines are not affected by exercise training in women.

It has been suggested that the abrupt liposuction-induced decrease in adipose tissue could affect adipokine secretion pattern. We hypothesized that exercise training could positively impact adipokine metabolism following liposuction. The aim of this study was to investigate the effects of liposuction on inflammation-related adipokines in women who were either exercise-trained or remained sedentary after surgery. Thirty-six healthy normal-weight women underwent an abdominal liposuction and two months after surgery were randomly allocated into two groups: trained (TR, n = 18, four-month exercise program) and nontrained (NT, n = 18). Inflammation-related adipokine serum levels (TNF- α , IL-6, IL-10, and adiponectin) and abdominal and thigh subcutaneous adipose tissue (scAT) mRNA levels were assessed before (PRE) and six months after surgery (POST6). TNF- α , IL-6, and IL-10 serum levels were unchanged in both groups. In contrast, TNF- α , IL-6, and IL-10 mRNA levels in scAT were increased, whereas adiponectin scAT mRNA and serum levels were decreased at POST6 (P < 0.05, main effect for time). No changes were observed in mRNA levels of MCP-1, CD14, and CD68 in any of the groups. In conclusion, liposuction downregulates adiponectin scAT gene expression and serum levels and upregulates scAT gene expression of inflammation-related genes six months after surgery in normal-weight women, irrespective of exercise training.

Influence of training status on high-intensity intermittent performance in response to ß-alanine supplementation.

Recent investigations have suggested that highly trained athletes may be less responsive to the ergogenic effects of ß-alanine (BA) supplementation than recreationally active individuals due to their elevated muscle buffering capacity. We investigated whether training status influences the effect of BA on repeated Wingate performance. Forty young males were divided into two groups according to their training status (trained: T, and non-trained: NT cyclists) and were randomly allocated to BA and a dextrose-based placebo (PL) groups, providing four experimental conditions: NTPL, NTBA, TPL, TBA. BA (6.4 g day(-1)) or PL was ingested for 4 weeks, with participants completing four 30-s lower-body Wingate bouts, separated by 3 min, before and after supplementation. Total work done was significantly increased following supplementation in both NTBA (p = 0.03) and TBA (p = 0.002), and it was significantly reduced in NTPL (p = 0.03) with no difference for TPL (p = 0.73). BA supplementation increased mean power output (MPO) in bout 4 for the NTBA group (p = 0.0004) and in bouts 1, 2 and 4 for the TBA group (p ≤ 0.05). No differences were observed in MPO for NTPL and TPL. BA supplementation was effective at improving repeated high-intensity cycling performance in both trained and non-trained individuals, highlighting the efficacy of BA as an ergogenic aid for high-intensity exercise regardless of the training status of the individual.

Brain creatine depletion in vegetarians? A cross-sectional ¹H-magnetic resonance spectroscopy (¹H-MRS) study.

The present cross-sectional study aimed to examine the influence of diet on brain creatine (Cr) content by comparing vegetarians with omnivores. Brain Cr content in the posterior cingulate cortex was assessed by proton magnetic resonance spectroscopy (¹H-MRS). Dietary Cr intake was assessed by 3 d food recalls. Vegetarians had lower dietary Cr intake than omnivores (0.03 (SD 0.01) v. 1.34 (SD 0.62) g/d, respectively; P=0.005). However, vegetarians and omnivores had comparable brain total Cr content (5.999 (SD 0.811) v. 5.917 (SD 0.665) IU, respectively; P=0.77). In conclusion, dietary Cr did not influence brain Cr content in healthy individuals, suggesting that in normal conditions brain is dependent on its own Cr synthesis.

Eficácia e segurança da suplementação de creatina em pacientes com dermatomiosite de início juvenil / Safety and efficacy of creatine supplementation in juvenile dermatomyositis

Introdução: A dermatomiosite juvenil (DMJ) é uma doença autoimune idiopática caracterizada pela presença de lesão cutânea, perda de massa muscular, fraqueza muscular proximal, fadiga e redução da aptidão física. Nesse contexto, a suplementação de creatina emerge como estratégia terapêutica não farmacológica para atenuar os sintomas ocasionados pela disfunção muscular e perda de massa muscular em diversas condições, como nas doenças reumatológicas pediátricas; Objetivo: O objetivo deste estudo foi avaliar a eficácia e a segurança da suplementação de creatina em pacientes com DM de início juvenil; Métodos: Trata-se de um estudo duplo-cego, crossover, balanceado e controlado por placebo. Todos os voluntários (n = 15) receberam dois tratamentos, a saber: creatina (0,1 g/kg/dia) ou dextrose (placebo - 0,1 g/kg/dia). Para cada tratamento, o período de suplementação foi de 12 semanas, interpassadas por um período de washout de oito semanas. A ordem dos tratamentos foi determinada de forma aleatória e contrabalanceada. Tanto nos períodos pré-suplementação, como nos períodos pós-suplementação foram avaliadas a força e função musculares (desfechos primários), além da composição corporal, densidade mineral óssea, marcadores bioquímicos do remodelamento ósseo, citocinas inflamatórias, aptidão aeróbia, qualidade de vida, parâmetros relacionados à atividade da doença, consumo alimentar e conteúdo intramuscular de fosforilcreatina. Nos mesmos períodos de tempo, a segurança da intervenção foi avaliada por parâmetros laboratoriais e por clearance de 51Cr-EDTA. Os eventos adversos foram registrados durante todo o estudo; Resultados: Não houve diferença significativa no conteúdo intramuscular de fosforilcreatina entre as condições, antes e após as intervenções (Creatina - Pré: 21,4 ± 5,3/Pós: 20,6 ± 2,7, delta escore = -0,3 ± 2,5 mmol/kg peso úmido; Placebo - Pré: 20,4 ± 3,7/Pós: 20,7 ± 3,6, delta escore = -0,1 ± 4,2 mmol/kg peso úmido, p = 0,45...

Introduction: Juvenile dermatomyositis (JDM) is an autoimmune idiopathic disease characterized by skin rashes, insidious loss of muscle mass, symmetrical proximal muscle weakness, decreased physical capacity, and fatigue. In this context, creatine supplementation has emerged as a promising non-pharmacological therapeutic strategy to counteract muscle dysfunction and low lean mass in a variety of conditions, including in pediatric and rheumatic diseases. Objective: To examine the safety and efficacy of creatine supplementation in Juvenile Dermatomyositis (JDM) patients; Methods: JDM patients (n = 15) received placebo or creatine supplementation (0.1 g/kg/d) in a randomized, crossover, double-blind design. Subjects were assessed at baseline and after 12 weeks, with an 8-week washout period. Primary outcome was muscle function. Secondary outcomes included body composition, bone mineral density, biochemical markers of bone remodeling, inflammatory cytokines, aerobic conditioning, health-related quality of life, disease-related parameters, dietary intake and muscle phosphorylcreatine (PCR) content. Safety was assessed by laboratory parameters and kidney function measurements such as 51Cr-EDTA clearance; Results: Intramuscular PCR content was not significantly different between creatine and placebo before or after the intervention (Creatine - Pre: 21.4 ± 5.3, Post: 20.6 ± 2.7, delta score = -0.3 ± 2.5 mmol/kg wet muscle, ES = -0.15; Placebo - Pre: 20.4 ± 3.7, Post: 20.7 ± 3.6, delta score = -0.1 ± 4.2 mmol/kg wet muscle, ES = -0.15; 95% CI for delta score = -2.8 ± 2.4, p = 0.45...

Effect of rapid weight loss on performance in combat sport male athletes: does adaptation to chronic weight cycling play a role?

BACKGROUND: Studies failing to show a negative effect of rapid weight loss (RWL) on performance have been conducted in athletes who have been cycling weight for years. It has been suggested that chronic weight cycling could lead combat athletes to become resistant to the stresses associated with weight loss. To investigate the effects of RWL up to 5% of body mass on high-intensity intermittent performance in weight cyclers (WC) and non-weight cyclers (non-WC). METHODS: Eighteen male combat athletes (WC: n=10; non-WC: n=8) reduced up to 5% of their body mass in 5 days. Body composition, high-intensity performance and plasma lactate were assessed preweight loss and postweight loss. Athletes had 4 h to re-feed and rehydrate following the weigh-in. Food intake was recorded during the weight loss and the recovery periods. RESULTS: Athletes significantly decreased body mass, lean body mass (most likely due to fluid loss) and fat mass following weight loss. No significant changes in performance were found from preweight loss to postweight loss in both groups. Plasma lactate was significantly elevated after exercise in both groups, but no differences were found between groups and in response to RWL. For all these variables no differences were observed between groups. Athletes from both groups ingested high amounts of energy and carbohydrates during the recovery period after the weigh-in. CONCLUSIONS: Chronic weight cycling does not protect athletes from the negative impact of RWL on performance. The time to recover after weigh-in and the patterns of food and fluid ingestion during this period is likely to play the major role in restoring performance to baseline levels.

The ergogenic effect of beta-alanine combined with sodium bicarbonate on high-intensity swimming performance.

We investigated the effect of beta-alanine (BA) alone (study A) and in combination with sodium bicarbonate (SB) (study B) on 100- and 200-m swimming performance. In study A, 16 swimmers were assigned to receive either BA (3.2 g·day(-1) for 1 week and 6.4 g·day(-1) for 4 weeks) or placebo (PL; dextrose). At baseline and after 5 weeks of supplementation, 100- and 200-m races were completed. In study B, 14 were assigned to receive either BA (3.2 g·day(-1) for 1 week and 6.4 g·day(-1) for 3 weeks) or PL. Time trials were performed once before and twice after supplementation (with PL and SB), in a crossover fashion, providing 4 conditions: PL-PL, PL-SB, BA-PL, and BA-SB. In study A, BA supplementation improved 100- and 200-m time-trial performance by 2.1% (p = 0.029) and 2.0% (p = 0.0008), respectively. In study B, 200-m time-trial performance improved in all conditions, compared with presupplementation, except the PL-PL condition (PL-SB, +2.3%; BA-PL, +1.5%; BA-SB, +2.13% (p < 0.05)). BA-SB was not different from BA-PL (p = 0.21), but the probability of a positive effect was 78.5%. In the 100-m time-trial, only a within-group effect for SB was observed in the PL-SB (p = 0.022) and BA-SB (p = 0.051) conditions. However, 6 of 7 athletes swam faster after BA supplementation. The probability of BA having a positive effect was 65.2%; when SB was added to BA, the probability was 71.8%. BA and SB supplementation improved 100- and 200-m swimming performance. The coingestion of BA and SB induced a further nonsignificant improvement in performance.

Acute effects of isocaloric meals with different fiber and antioxidant contents on inflammatory markers in healthy individuals.

Chronic inflammation contributes to the pathophysiology of many chronic diseases. Dietary fibers and antioxidants may exert anti-inflammatory effects. The objective of this study was to determine whether meals with different fibers and antioxidants may elicit a different response in inflammatory markers in healthy volunteers. On 3 separate days, subjects (n = 8) consumed one of three isocaloric meals with different antioxidant (vitamin E, selenium and ß-carotene) and fiber content (high, intermediate and low) in a randomized crossover design. Blood samples were collected at different times: 0 min (before the meal), and 30 and 240 min after the meal. Plasma interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, glucose and insulin content were evaluated at each time point. There were no significant differences for any of the parameters at baseline. Furthermore, plasma levels of TNF-α, IL-6 and IL-10 were unchanged at the 30- and 240-min time points whatever meal consumed. Moreover, the cytokine responses to glucose and insulin intake were not significantly different between experimental conditions. In conclusion, isocaloric meals with different fiber, ß-carotene, vitamin E and selenium contents do not acutely affect inflammatory markers in healthy young males.