Wool keratin - A novel dietary protein source: Nutritional value and toxicological assessment.

Keratin derived protein (KDP) was extracted from sheep wool using high pressure microwave technology and food acids and investigated for its potential as a novel dietary protein. The proximate composition, amino acid profile, element profile, in vitro cytotoxicity and digestibility of KDP were evaluated. Nutritive effects of KDP at 50% dietary supplementation were compared with a casein-based diet in a growing rat model for 95 days. Results indicate KDP to be rich in protein (86%), amino acid cysteine (8.8 g/100 g) and element selenium (0.29 µg/g). KDP was non-cytotoxic in vitro at ≤ 2 mg/mL concentration. There were no differences in the rat's weight gain compared to the control group (P > 0.05). Overall, the inclusion of the KDP in the diet was an effective substitute for casein protein at 50% and KDP has the potential to be used in the food industry as a novel dietary protein, free of fat and carbohydrate.

Effects of whey protein on skeletal muscle microvascular and mitochondrial plasticity following 10 weeks of exercise training in men with type 2 diabetes.

Skeletal muscle microvascular dysfunction and mitochondrial rarefaction feature in type 2 diabetes mellitus (T2DM) linked to low tissue glucose disposal rate (GDR). Exercise training and milk protein supplementation independently promote microvascular and metabolic plasticity in muscle associated with improved nutrient delivery, but combined effects are unknown. In a randomised-controlled trial, 24 men (55.6 y, SD 5.7) with T2DM ingested whey protein drinks (protein/carbohydrate/fat: 20/10/3 g; WHEY) or placebo (carbohydrate/fat: 30/3 g; CON) before/after 45 mixed-mode intense exercise sessions over 10 weeks, to study effects on insulin-stimulated (hyperinsulinemic clamp) skeletal-muscle microvascular blood flow (mBF) and perfusion (near-infrared spectroscopy), and histological, genetic, and biochemical markers (biopsy) of microvascular and mitochondrial plasticity. WHEY enhanced insulin-stimulated perfusion (WHEY-CON 5.6%; 90% CI -0.1, 11.3), while mBF was not altered (3.5%; -17.5, 24.5); perfusion, but not mBF, associated (regression) with increased GDR. Exercise training increased mitochondrial (range of means: 40%-90%) and lipid density (20%-30%), enzyme activity (20%-70%), capillary:fibre ratio (∼25%), and lowered systolic (∼4%) and diastolic (4%-5%) blood pressure, but without WHEY effects. WHEY dampened PGC1α -2.9% (90% compatibility interval: -5.7, -0.2) and NOS3 -6.4% (-1.4, -0.2) expression, but other messenger RNA (mRNA) were unclear. Skeletal muscle microvascular and mitochondrial exercise adaptations were not accentuated by whey protein ingestion in men with T2DM. ANZCTR Registration Number: ACTRN12614001197628. Novelty: Chronic whey ingestion in T2DM with exercise altered expression of several mitochondrial and angiogenic mRNA. Whey added no additional benefit to muscle microvascular or mitochondrial adaptations to exercise. Insulin-stimulated perfusion increased with whey but was without impact on glucose disposal.

Probiotic Streptococcus thermophilus FP4 and Bifidobacterium breve BR03 Supplementation Attenuates Performance and Range-of-Motion Decrements Following Muscle Damaging Exercise.

Probiotics have immunomodulatory effects. However, little is known about the potential benefit of probiotics on the inflammation subsequent to strenuous exercise. In a double-blind, randomized, placebo controlled, crossover design separated by a 21-day washout, 15 healthy resistance-trained men ingested an encapsulated probiotic Streptococcus (S.) thermophilus FP4 and Bifidobacterium (B.) breve BR03 at 5 bn live cells (AFU) concentration each, or a placebo, daily for 3 weeks prior to muscle-damaging exercise (ClinicalTrials.gov NCT02520583). Isometric strength, muscle soreness, range of motion and girth, and blood interleukin-6 (IL-6) and creatine kinase (CK) concentrations were measured from pre- to 72 h post-exercise. Statistical analysis was via mixed models and magnitude-based inference to the standardized difference. Probiotic supplementation resulted in an overall decrease in circulating IL-6, which was sustained to 48 h post-exercise. In addition, probiotic supplementation likely enhanced isometric average peak torque production at 24 to 72 h into the recovery period following exercise (probiotic-placebo point effect ±90% CI: 24 h, 11% ± 7%; 48 h, 12% ± 18%; 72 h, 8% ± 8%). Probiotics also likely moderately increased resting arm angle at 24 h (2.4% ± 2.0%) and 48 h (1.9% ± 1.9%) following exercise, but effects on soreness and flexed arm angle and CK were unclear. These data suggest that dietary supplementation with probiotic strains S. thermophilus FP4 and B. breve BR03 attenuates performance decrements and muscle tension in the days following muscle-damaging exercise.

Curcumin supplementation likely attenuates delayed onset muscle soreness (DOMS).

INTRODUCTION: Oral curcumin decreases inflammatory cytokines and increases muscle regeneration in mice. PURPOSE: To determine effects of curcumin on muscle damage, inflammation and delayed onset muscle soreness (DOMS) in humans. METHOD: Seventeen men completed a double-blind randomized-controlled crossover trial to estimate the effects of oral curcumin supplementation (2.5 g twice daily) versus placebo on single-leg jump performance and DOMS following unaccustomed heavy eccentric exercise. Curcumin or placebo was taken 2 d before to 3 d after eccentric single-leg press exercise, separated by 14-d washout. Measurements were made at baseline, and 0, 24 and 48-h post-exercise comprising: (a) limb pain (1-10 cm visual analogue scale; VAS), (b) muscle swelling, (c) single-leg jump height, and (d) serum markers of muscle damage and inflammation. Standardized magnitude-based inference was used to define outcomes. RESULTS: At 24 and 48-h post-exercise, curcumin caused moderate-large reductions in pain during single-leg squat (VAS scale -1.4 to -1.7; 90 %CL: ±1.0), gluteal stretch (-1.0 to -1.9; ±0.9), squat jump (-1.5 to -1.1; ± 1.2) and small reductions in creatine kinase activity (-22-29 %; ±21-22 %). Associated with the pain reduction was a small increase in single-leg jump performance (15 %; 90 %CL ± 12 %). Curcumin increased interleukin-6 concentrations at 0-h (31 %; ±29 %) and 48-h (32 %; ±29 %) relative to baseline, but decreased IL-6 at 24-h relative to post-exercise (-20 %; ±18 %). CONCLUSIONS: Oral curcumin likely reduces pain associated with DOMS with some evidence for enhanced recovery of muscle performance. Further study is required on mechanisms and translational effects on sport or vocational performance.

Impact of autologous blood injections in treatment of mid-portion Achilles tendinopathy: double blind randomised controlled trial.

OBJECTIVE: To assess the effectiveness of two peritendinous autologous blood injections in addition to a standardised eccentric calf strengthening programme in improving pain and function in patients with mid-portion Achilles tendinopathy. DESIGN: Single centre, participant and single assessor blinded, parallel group, randomised, controlled trial. SETTING: Single sports medicine clinic in New Zealand. PARTICIPANTS: 53 adults (mean age 49, 53% men) with symptoms of unilateral mid-portion Achilles tendinopathy for at least three months. Participants were excluded if they had a history of previous Achilles tendon rupture or surgery or had undergone previous adjuvant treatments such as injectable therapies, glyceryl trinitrate patches, or extracorporeal shockwave therapy. INTERVENTIONS: All participants underwent two unguided peritendinous injections one month apart with a standardised protocol. The treatment group had 3 mL of their own whole blood injected while the control group had no substance injected (needling only). Participants in both groups carried out a standardised and monitored 12 week eccentric calf training programme. Follow-up was at one, two, three and six months. MAIN OUTCOME MEASURES: The primary outcome measure was the change in symptoms and function from baseline to six months with the Victorian Institute of Sport Assessment-Achilles (VISA-A) score. Secondary outcomes were the participant's perceived rehabilitation and their ability to return to sport. RESULTS: 26 participants were randomly assigned to the treatment group and 27 to the control group. In total, 50 (94%) completed the six month study, with 25 in each group. Clear and clinically worthwhile improvements in the VISA-A score were evident at six months in both the treatment (change in score 18.7, 95% confidence interval 12.3 to 25.1) and control (19.9, 13.6 to 26.2) groups. The overall effect of treatment was not significant (P=0.689) and the 95% confidence intervals at all points precluded clinically meaningful benefit or harm. There was no significant difference between groups in secondary outcomes or in the levels of compliance with the eccentric calf strengthening programme. No adverse events were reported. CONCLUSION: The administration of two unguided peritendinous autologous blood injections one month apart, in addition to a standardised eccentric training programme, provides no additional benefit in the treatment of mid-portion Achilles tendinopathy. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12610000824066, WHO U1111-1117-2641.

Effect of post-exercise protein-leucine feeding on neutrophil function, immunomodulatory plasma metabolites and cortisol during a 6-day block of intense cycling.

Whey protein and leucine ingestion following exercise increases muscle protein synthesis and could influence neutrophil function during recovery from prolonged intense exercise. We examined the effects of whey protein and leucine ingestion post-exercise on neutrophil function and immunomodulators during a period of intense cycling. In a randomized double-blind crossover, 12 male cyclists ingested protein/leucine/carbohydrate/fat (LEUPRO 20/7.5/89/22 g h(-1), respectively) or isocaloric carbohydrate/fat control (CON 119/22 g h(-1)) beverages for 1-3 h post-exercise during 6 days of high-intensity training. Blood was taken pre- and post-exercise on days 1, 2, 4 and 6 for phorbol myristate acetate (PMA)-stimulated neutrophil superoxide (O2 (-)) production, immune cell counts, amino acid and lipid metabolism via metabolomics, hormones (cortisol, testosterone) and cytokines (interleukin-6, interleukin-10). During recovery on day 1, LEUPRO ingestion increased mean concentrations of plasma amino acids (glycine, arginine, glutamine, leucine) and myristic acid metabolites (acylcarnitines C14, myristoylcarnitine; and C14:1-OH, hydroxymyristoleylcarnitine) with neutrophil priming capacity, and reduced neutrophil O2 production (15-17 mmol O2 (-) cell(-1) ± 90 % confidence limits 20 mmol O2 (-) cell(-1)). On day 2, LEUPRO increased pre-exercise plasma volume (6.6 ± 3.8 %) but haematological effects were trivial. LEUPRO supplementation did not substantially alter neutrophil elastase, testosterone, or cytokine concentrations. By day 6, however, LEUPRO reduced pre-exercise cortisol 21 % (±15 %) and acylcarnitine C16 (palmitoylcarnitine) during exercise, and increased post-exercise neutrophil O2 (-) (33 ± 20 mmol O2 (-) cell(-1)), relative to control. Altered plasma amino acid and acylcarnitine concentrations with protein-leucine feeding might partly explain the acute post-exercise reduction in neutrophil function and increased exercise-stimulated neutrophil oxidative burst on day 6, which could impact neutrophil-dependent processes during recovery from intense training.

Leucine-protein supplemented recovery feeding enhances subsequent cycling performance in well-trained men.

The purpose of this study was to determine whether a practical leucine-protein, high-carbohydrate postexercise feeding regimen could improve recovery, as measured by subsequent cycling performance and mechanistic markers, relative to control feeding. In a crossover, 10 male cyclists performed 2- to 2.5-h interval training bouts on 3 consecutive evenings, ingesting either leucine-protein, high-carbohydrate nutrition (0.1/0.4/1.2/0.2 g·kg(-1)·h(-1); leucine, protein, carbohydrate, fat, respectively) or isocaloric control (0.06/1.6/0.2 g·kg(-1)·h(-1); protein, carbohydrate, fat, respectively) nutrition for 1.5 h postexercise. Throughout the experimental period diet was controlled, energy and macronutrient intake balanced, and protein intake clamped at 1.6 g·kg(-1)·day(-1). The alternate supplement was provided the next morning, thereby isolating the postexercise nutrition effect. Following 39 h of recovery, cyclists performed a repeat-sprint performance test. Postexercise leucine-protein ingestion improved mean sprint power by 2.5% (99% confidence limit, ±2.6%; p = 0.013) and reduced perceived overall tiredness during the sprints by 13% (90% confidence limit, ±9.2%), but perceptions of leg tiredness and soreness were unaffected. Before exercise, creatine-kinase concentration was lowered by 19% (90% confidence limits, ±18%), but lactate dehydrogenase and pressure-pain threshold were unaltered. There was a small reduction in anger (25% ± 18%), but other moods were unchanged. Plasma leucine (3-fold) and essential amino acid (47%) concentrations were elevated postexercise. Net nitrogen balance trended mildly negative in both conditions (mean ± SD: leucine-protein, -20 ± 46 mg·kg(-1) per 24 h; control, -25 ± 36 mg·kg(-1) per 24 h). The ingestion of a leucine-protein supplement along with other high-carbohydrate food following intense training on consecutive days enhances subsequent high-intensity endurance performance and may attenuate muscle membrane disruption in well-trained male cyclists.

Effects of beta-hydroxy-beta-methylbutyrate supplementation during resistance training on strength, body composition, and muscle damage in trained and untrained young men: a meta-analysis.

Beta-hydroxy-beta-methylbutyrate (HMB) is a popular supplement in the resistance training community, with its use supported by claims of increased strength, muscle growth, and improved recovery; however, research outcomes are variable. Therefore, we meta-analyzed the effectiveness of HMB on strength, body composition, and muscle damage. Nine qualifying studies yielded 14 comparisons subcategorized by training experience (trained, untrained) to provide 12-13 estimates of strength (upper body, lower body, overall average), 13 estimates of fat and fat-free mass, and 7 estimates of the muscle-damage marker creatine kinase. The meta-analysis comprised 394 subjects (age 23 +/- 2 years, mean +/- between-study SD) with 5 +/- 2 weeks' intervention and 5 +/- 6 h.wk of training. The estimates were analyzed using a meta-analytic mixed model with study sample size as the weighting factor that included the main-effect covariates to control for between-study differences in HMB dose, intervention duration, training load, and dietary cointervention. To interpret magnitudes, meta-analyzed effects were standardized using the composite baseline between-subject SD and were qualified using modified Cohen effect size thresholds. There were small benefits to lower-body (mean +/- 90% confidence limit: 9.9% +/- 5.9%) and average strength (6.6 +/- 5.7%), but only negligible gains for upper-body strength (2.1 +/- 5.5%) were observed in untrained lifters. In trained lifters, all strength outcomes were trivial. Combined (all studies), the overall average strength increase was trivial (3.7 +/- 2.4%), although uncertainty allows for a small benefit. Effects on fat and fat-free mass were trivial, and results regarding creatine kinase were unclear. Supplementation with HMB during resistance training incurs small but clear overall and leg strength gains in previously untrained men, but effects in trained lifters are trivial. The HMB effect on body composition is inconsequential. An explanation for strength gains in previously untrained lifters requires further research.

Effects of nine weeks of beta-hydroxy-beta- methylbutyrate supplementation on strength and body composition in resistance trained men.

The dietary supplement beta-hydroxy-beta-methylbutyrate (HMB) is claimed to increase strength, lean body mass, and decrease fat mass when used in conjunction with resistance training. Although there is some support for these claims, the evidence is not conclusive, and it is even less so for resistance trained individuals. Therefore, we aimed to further elucidate the effects of HMB supplementation in trained men. A randomized, double-blind, controlled study design was used to investigate the effects of supplementing 22 resistance trained men with 3 g.d of HMB or corn starch placebo for 9 weeks with resistance training. The effect of HMB on strength was determined using the 1-repetition maximum (1RM) method for the lower body (leg extension) and upper body (bench press, bicep preacher curl) at baseline and after the supplementation period. Body composition was assessed by skinfolds and bioelectrical impedance analysis (BIA). Overall, 9 weeks' HMB supplementation resulted in a clear-cut, trivial increase in combined averaged strength measures of 1.6% (90% confidence limits: +/-4.3%). When considered in isolation, however, leg extension 1RM increased by a substantial 9.1% (90% confidence limits: +/-7.5%), but the effect on upper-body strength was inconclusive (bench press: -1.9 +/- 9.3%; bicep curl: -1.7 +/- 4.7%). Based on BIA estimates, HMB had a decreasing (although inconclusive) influence on fat mass of -9 +/- 14%, but it had a clear, trivial effect on fat-free mass of 0.2 +/- 2.2%. The magnitude of change in body mass was trivial, but the probability of substantial reductions in skinfold thicknesses ranged from negligible to likely. In previously trained men, supplementation of HMB in conjunction with resistance training provides a substantial benefit to lower-body strength, but it has negligible effects on body composition.

Attenuated gastric distress but no benefit to performance with adaptation to octanoate-rich esterified oils in well-trained male cyclists.

We investigated the effects of modifying a normal dietary fatty acid composition and ingestion of high-fat exercise supplements on gastrointestinal distress, substrate oxidation, and endurance cycling performance. Nine well-trained male cyclists completed a randomized triple-crossover comprising a 2-wk diet high in octanoate-rich esterified oil (MCFA) or twice long-chain fatty acids (LCFA). Following the diets, participants performed 3-h of cycling at 50% of peak power followed by 10 maximal sprints while ingesting either 1) a carbohydrate (CHO)+MCFA-rich oil emulsion after the 2-wk MCFA-rich dietary condition (MC-MC, Intervention) and 2) after one of the LCFA-rich dietary conditions (LC-MC, Placebo) or 3) CHO only following a LCFA-rich diet (LC-CHO, Control). During the 3-h ride MCFA-adaptation decreased octanoic-acid oxidation by 24% (90% confidence interval: 14-34%). The CHO+MCFA-rich oil emulsion reduced endogenous fat oxidation by 61% (33-89%) and 110% (89-131%) in the MC-MC and LC-MC conditions, respectively, and MCFA-adaptation reduced endogenous-carbohydrate oxidation by 10% (-3-23%). MCFA-adaptation attenuated gastrointestinal distress and nausea during the sprints, but the effect of the oil emulsion was to lower sprint power by 10.9% (7.7-14.1%) in the LC-MC condition and by 7.1% (5.7-8.5%) in the MC-MC condition, relative to the LC-CHO control; every one unit increase in nausea decreased mean power by 6.0 W (3.2-8.8 W). We conclude that despite some attenuation of endogenous-carbohydrate oxidation and gastric distress following adaptation to a MCFA-rich diet, repeat sprint performance was substantially impaired in response to the ingestion of a CHO+MCFA-rich oil emulsion.