Screening for recombinant human erythropoietin using [Hb], reticulocytes, the OFFhrscore, OFF z score and Hb z score: status of the Blood Passport

Haemoglobin concentration ([Hb]), reticulocyte percentage (retic%) and OFFhrscore are well-implemented screening tools to determine potential recombinant human erythropoietin (rHuEpo) abuse in athletes. Recently, the International Cycling Union implemented the OFFzscore and the Hbzscore in their anti-doping testing programme. The aim of this study is to evaluate the sensitivity of these indirect screening methods. Twenty-four human subjects divided into three groups with eight subjects each (G1; G2 and G3) were injected with rHuEpo. G1 and G2 received rHuEpo for a 4-week period with 2weeks of "boosting” followed by 2weeks of "maintenance” and a wash-out period of 3weeks. G3 received rHuEpo for a 10-week period (boost=3weeks; maintenance=7weeks; wash out=1week). Three, seven and eight of the 24 volunteers exceeded the cut-off limits for OFFhrscore, [Hb] and retic%, respectively. One subject from G1, nobody from G2, and seven subjects from G3 exceeded the cut-off limit for Hbzscore. In total, ten subjects exceeded the cut-off limit for the OFFzscore; two subjects from G1, two subjects from G2 and six subjects from G3. In total, indirect screening methods were able to indicate rHuEpo injections in 58% of subjects. However, 42% of our rHuEpo-injected subjects were not detected. It should be emphasised that the test frequency in real world anti-doping is far less than the present study, and hence the detection rate will be lowe

Probiotic supplementation prevents high-fat, overfeeding-induced insulin resistance in human subjects

The purpose of the present study was to determine whether probiotic supplementation (Lactobacillus casei Shirota (LcS)) prevents diet-induced insulin resistance in human subjects. A total of seventeen healthy subjects were randomised to either a probiotic (n 8) or a control (n 9) group. The probiotic group consumed a LcS-fermented milk drink twice daily for 4 weeks, whereas the control group received no supplementation. Subjects maintained their normal diet for the first 3 weeks of the study, after which they consumed a high-fat (65 % of energy), high-energy (50 % increase in energy intake) diet for 7 d. Whole-body insulin sensitivity was assessed by an oral glucose tolerance test conducted before and after overfeeding. Body mass increased by 0·6 (se 0·2) kg in the control group (P0·05). Fasting plasma glucose concentrations increased following 7 d of overeating (control group: 5·3 (se 0·1) v. 5·6 (se 0·2) mmol/l before and after overfeeding, respectively, P0·05). These results suggest that probiotic supplementation may be useful in the prevention of diet-induced metabolic diseases such as type 2 diabetes

A single day of excessive dietary fat intake reduces whole-body insulin sensitivity: the metabolic consequence of binge eating

Consuming excessive amounts of energy as dietary fat for several days or weeks can impair glycemic control and reduce insulin sensitivity in healthy adults. However, individuals who demonstrate binge eating behavior overconsume for much shorter periods of time; the metabolic consequences of such behavior remain unknown. The aim of this study was to determine the effect of a single day of high-fat overfeeding on whole-body insulin sensitivity. Fifteen young, healthy adults underwent an oral glucose tolerance test before and after consuming a high-fat (68% of total energy), high-energy (78% greater than daily requirements) diet for one day. Fasting and postprandial plasma concentrations of glucose, insulin, non-esterified fatty acids, and triglyceride were measured and the Matsuda insulin sensitivity index was calculated. One day of high-fat overfeeding increased postprandial glucose area under the curve (AUC) by 17.1% (p < 0.0001) and insulin AUC by 16.4% (p = 0.007). Whole-body insulin sensitivity decreased by 28% (p = 0.001). In conclusion, a single day of high-fat, overfeeding impaired whole-body insulin sensitivity in young, healthy adults. This highlights the rapidity with which excessive consumption of calories through high-fat food can impair glucose metabolism, and suggests that acute binge eating may have immediate metabolic health consequences for the individual

Cow's milk as a post-exercise recovery drink: implications for performance and health

Post-exercise recovery is a multi-facetted process that will vary depending on the nature of the exercise, the time between exercise sessions and the goals of the exerciser. From a nutritional perspective, the main considerations are: (1) optimisation of muscle protein turnover; (2) glycogen resynthesis; (3) rehydration; (4) management of muscle soreness; (5) appropriate management of energy balance. Milk is approximately isotonic (osmolality of 280–290 mosmol/kg), and the mixture of high quality protein, carbohydrate, water and micronutrients (particularly sodium) make it uniquely suitable as a post-exercise recovery drink in many exercise scenarios. Research has shown that ingestion of milk post-exercise has the potential to beneficially impact both acute recovery and chronic training adaptation. Milk augments post-exercise muscle protein synthesis and rehydration, can contribute to post-exercise glycogen resynthesis, and attenuates post-exercise muscle soreness/function losses. For these aspects of recovery, milk is at least comparable and often out performs most commercially available recovery drinks, but is available at a fraction of the cost, making it a cheap and easy option to facilitate post-exercise recovery. Milk ingestion post-exercise has also been shown to attenuate subsequent energy intake and may lead to more favourable body composition changes with exercise training. This means that those exercising for weight management purposes might be able to beneficially influence post-exercise recovery, whilst maintaining the energy deficit created by exercise

Addition of sodium alginate and pectin to a carbohydrate-electrolyte solution does not influence substrate oxidation, gastrointestinal comfort, or cycling performance

Eight well-trained cyclists ingested 68 g·h-1 of a carbohydrate-electrolyte solution with sodium alginate and pectin (CHO-ALG) or a taste and carbohydrate-type matched carbohydrate-electrolyte solution (CHO) during 120 min cycling at 55% Wmax followed by a ~20 min time trial. V̇O2, V̇CO2 blood glucose concentration, substrate oxidation, gastrointestinal symptoms and time trial performance (CHO-ALG: 1219 ± 84 s, CHO: 1267 ± 102 s; P = 0.185) were not different between trials. Novelty bullet: • Inclusion of sodium alginate and pectin in a carbohydrate drink does not influence blood glucose, substrate oxidation, gastrointestinal comfort or performance in cyclists

Short-term, high-fat overfeeding impairs glycaemic control but does not alter gut hormone responses to a mixed meal tolerance test in healthy, normal-weight individuals

Obesity is undoubtedly caused by a chronic positive energy balance. However, the early metabolic and hormonal responses to overeating are poorly described. This study determined glycaemic control and selected gut hormone responses to nutrient intake before and after seven days of high-fat overfeeding. Nine healthy individuals (5 males, 4 females) performed a mixed meal tolerance test (MTT) before and after consuming a high-fat (65%) high-energy (+50%) diet for seven days. Measurements of plasma glucose, NEFA, acylated ghrelin, GLP-1, GIP and serum insulin were taken before (fasting) and at 30 minutes intervals throughout the 180 min MTT (postprandial). Body mass increased by 0.79 ± 0.14 kg after high-fat overfeeding (p < 0.0001), and BMI increased by 0.27 ± 0.05 kg/m2 (p = 0.002). High-fat overfeeding also resulted in an 11.6% increase in postprandial glucose AUC (p = 0.007) and a 25.9% increase in postprandial insulin AUC (p = 0.005). Acylated ghrelin, GLP-1 and GIP responses to the MTT were all unaffected by the high-fat, high-energy diet. These findings demonstrate that even brief periods of overeating are sufficient to disrupt glycaemic control. However, as the postprandial orexigenic (ghrelin) and anorexigenic/insulintropic (GLP-1 and GIP) hormone responses were unaffected by the diet intervention, it appears that these hormones are resistant to short-term changes in energy balance, and that they do not play a role in the rapid reduction in glycaemic control

24 h severe energy restriction impairs post-prandial glycaemic control in young, lean males

Intermittent energy restriction (IER) involves short periods of severe energy restriction interspersed with periods of adequate energy intake, and can induce weight loss. Insulin sensitivity is impaired by short-term, complete energy restriction, but the effects of IER are not well known. In randomised order, 14 lean men (age: 25 (SD 4) y; BMI: 24 (SD 2) kg·m-2; body fat: 17 (4) %) consumed 24 h diets providing 100% (10441 (SD 812) kJ; EB) or 25% (2622 (SD 204) kJ; ER) of estimated energy requirements, followed by an oral glucose tolerance test (OGTT; 75g glucose drink) overnight fasted. Plasma/ serum glucose, insulin, non-esterified fatty acids (NEFA), glucagon-like peptide-1 (GLP-1), glucose-dependant insulinotropic peptide (GIP) and fibroblast growth factor-21 (FGF21) were assessed before and after (0 h) each 24 h dietary intervention, and throughout the 2 h OGTT. Homeostatic model assessment of insulin resistance (HOMA2-IR) assessed the fasted response and incremental (iAUC) or total (tAUC) area under the curve were calculated during the OGTT. At 0 h, HOMA2-IR was 23% lower after ER compared to EB (P<0.05). During the OGTT, serum glucose iAUC (P<0.001) serum insulin iAUC (P<0.05) and plasma NEFA tAUC (P<0.01) were greater during ER, but GLP-1 (P=0.161), GIP (P=0.473) and FGF21 (P=0.497) tAUC were similar between trials. These results demonstrate that severe energy restriction acutely impairs postprandial glycaemic control in lean men, despite reducing HOMA2-IR. Chronic intervention studies are required to elucidate the long-term effects of IER on indices of insulin sensitivity, particularly in the absence of weight loss

Influence of hyper-energetic, high-fat feeding on circulating hepatokines in healthy men: a randomised crossover study [Abstract]

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Self-control exertion and glucose supplementation prior to endurance performance

Objectives: Completion of a task requiring self-control may negatively impact on subsequent self-regulatory efforts. This study explored a) whether this effect occurs during a well-practiced endurance task, b) the potential for glucose supplementation to moderate this effect, and c) whether this effect differed over time. Method: Fourteen trained cyclists completed four simulated 16 km time trials on an electromagnetically braked cycle ergometer. Prior to each time trial, participants completed a congruent Stroop task or an incongruent Stroop task that required self-control. They also received either a glucose-based drink or placebo. Participants’ performance time and heart rate were recorded throughout the time trials. Results: Multilevel growth curve analysis revealed a significant three-way interaction between self-control, glucose, and time (b = -0.91; p = 0.02). When participants did not exert self-control (congruent Stroop) or consume glucose (placebo drink) they were slowest during the early stages of the time trial but quickest over the full distance. No differences were found in heart rate across the four conditions. Conclusions: Findings suggest that pacing may explain why self-control exertion interferes with endurance performance. Moreover, the debate revolving around depletion of self-control must consider that any observed effects may be dependent on the timing of performance inspection