Legal nutritional supplements during a sporting event

2008 ◽  
Vol 44 ◽  
pp. 45-62 ◽  
Author(s):  
Ceri Nicholas

Nutrition significantly influences sports performance; however, the efficacy of any nutritional supplement or strategy should be carefully considered in relation to the event and the sex, training and nutritional status of the participant. The causes of fatigue, mechanism of action, safety and legality of the supplement, together with the scientific evidence from studies with an appropriate experimental design, should all be taken into account before incorporating into the training and/or competition diet. The efficacy of ingesting nutritional supplements immediately before and/or during endurance exercise (duration 45–180 min) is reviewed in this chapter. The ingestion of CES (carbohydrate-electrolyte solutions) have been shown to improve both exercise capacity and performance, either due to the maintenance of euglycaemia throughout exercise or the sparing of muscle glycogen early on in exercise. The addition of caffeine to CES may improve endurance performance as a consequence of a reduced perception of effort. Research suggests that the addition of protein to CES may only be effective when a suboptimal amount of CHO (carbohydrate) is ingested during exercise (<60 g of CHO⋅h−1); however, recovery of performance may be enhanced due to a reduction in subsequent muscle soreness and the promotion of muscle protein synthesis after exercise. The findings from studies investigating the effects of ingesting MCTs (medium-chain triacylglycerols) and BCAAs (branched-chain amino acids), either on their own or in combination with CES, on endurance performance have been equivocal and therefore would not be recommended. Any nutritional strategy should be practised in training before being used during a competition.

Author(s):  
James P. White

Skeletal muscle protein synthesis is a highly complex process, influenced by nutritional status, mechanical stimuli, repair programs, hormones, and growth factors. The molecular aspects of protein synthesis are centered around the mTORC1 complex. However, the intricacies of mTORC1 regulation, both up and downstream, have expanded overtime. Moreover, the plastic nature of skeletal muscle makes it a unique tissue, having to coordinate between temporal changes in myofiber metabolism and hypertrophy/atrophy stimuli within a tissue with considerable protein content. Skeletal muscle manages the push and pull between anabolic and catabolic pathways through key regulatory proteins to promote energy production in times of nutrient deprivation or activate anabolic pathways in times of nutrient availability and anabolic stimuli. Branched-chain amino acids (BCAAs) can be used for both energy production and signaling to induce protein synthesis. The metabolism of BCAAs occur in tandem with energetic and anabolic processes, converging at several points along their respective pathways. The fate of intramuscular BCAAs adds another layer of regulation, which has consequences to promote or inhibit muscle fiber protein anabolism. This review will outline the general mechanisms of muscle protein synthesis and describe how metabolic pathways can regulate this process. Lastly, we will discuss how BCAA availability and demand coordinate with synthesis mechanisms and identify key factors involved in intramuscular BCAA trafficking.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 80-81
Author(s):  
Tanja Hess ◽  
Emily Kent ◽  
Renan Regatieri Casagrande ◽  
Christine Levihn ◽  
Grace Romo ◽  
...  

Abstract Antioxidant supplementation has been shown to decrease post exercise oxidative stress but can lead to decreased post-exercise muscle protein synthesis. The objective of this study was to compare the effects of the supplementation with a control feed with low antioxidant content (CONT) to a high antioxidant feed (AO), versus a high antioxidant and branched chain amino acid feed (BCAO) on post-exercise protein synthesis and oxidative stress. Our hypothesis is that supplementing AO with BCAO will reduce oxidative stress without hindering muscle protein synthesis. Eighteen mixed breed conditioned polo horses were assigned to one of the three treatments. All horses consumed CONT for 30 days and were then submitted to a lactate threshold test (LT). One hour after this and all LT, each group was assigned and given their treatments. LT were done at 15 and 30 days of supplementation. Blood was collected before, two and four hours after LT, and analyzed for oxidative stress based on glutathione peroxidase, superoxide dismutase and malondialdehyde concentrations by ELISA. Muscle biopsies were taken before and 4 hours after LT and analyzed for the expression of protein synthesis by RT-PCR. Results were analyzed in a mixed model by ANOVA and compared by LSM. A reduction of oxidative stress was found over time (P &lt; 0.050) with no treatment effect (P &gt;0.50). An upregulation of protein synthesis after exercise was found for muscle primers CD36, CPT1, DK4, MyF5, and Myogenin (P &lt; 0.050). There was a treatment by time effect for MyoD (P = 0.027), where AO was upregulated the most after exercise compared to BCAO and CONT. DK4 had a treatment by time effect trend (P = 0.073), where AO and BCAO were upregulated and CONT was unchanged after exercise. This study demonstrated post exercise muscle synthesis with no advantage of AO plus BCAO compared to AO.


1988 ◽  
Vol 254 (2) ◽  
pp. 579-584 ◽  
Author(s):  
P J Garlick ◽  
I Grant

Rates of muscle protein synthesis were measured in vivo in tissues of post-absorptive young rats that were given intravenous infusions of various combinations of insulin and amino acids. In the absence of amino acid infusion, there was a steady rise in muscle protein synthesis with plasma insulin concentration up to 158 mu units/ml, but when a complete amino acids mixtures was included maximal rates were obtained at 20 mu units/ml. The effect of the complete mixture could be reproduced by a mixture of essential amino acids or of branched-chain amino acids, but not by a non-essential mixture, alanine, methionine or glutamine. It is concluded that amino acids, particularly the branched-chain ones, increase the sensitivity of muscle protein synthesis to insulin.


2010 ◽  
Vol 299 (3) ◽  
pp. R935-R944 ◽  
Author(s):  
Charles H. Lang ◽  
Christopher J. Lynch ◽  
Thomas C. Vary

Endotoxin (LPS) and sepsis decrease mammalian target of rapamycin (mTOR) activity in skeletal muscle, thereby reducing protein synthesis. Our study tests the hypothesis that inhibition of branched-chain amino acid (BCAA) catabolism, which elevates circulating BCAA and stimulates mTOR, will blunt the LPS-induced decrease in muscle protein synthesis. Wild-type (WT) and mitochondrial branched-chain aminotransferase (BCATm) knockout mice were studied 4 h after Escherichia coli LPS or saline. Basal skeletal muscle protein synthesis was increased in knockout mice compared with WT, and this change was associated with increased eukaryotic initiation factor (eIF)-4E binding protein-1 (4E-BP1) phosphorylation, eIF4E·eIF4G binding, 4E-BP1·raptor binding, and eIF3·raptor binding without a change in the mTOR·raptor complex in muscle. LPS decreased muscle protein synthesis in WT mice, a change associated with decreased 4E-BP1 phosphorylation as well as decreased formation of eIF4E·eIF4G, 4E-BP1·raptor, and eIF3·raptor complexes. In BCATm knockout mice given LPS, muscle protein synthesis only decreased to values found in vehicle-treated WT control mice, and this ameliorated LPS effect was associated with a coordinate increase in 4E-BP1·raptor, eIF3·raptor, and 4E-BP1 phosphorylation. Additionally, the LPS-induced increase in muscle cytokines was blunted in BCATm knockout mice, compared with WT animals. In a separate study, 7-day survival and muscle mass were increased in BCATm knockout vs. WT mice after polymicrobial peritonitis. These data suggest that elevating blood BCAA is sufficient to ameliorate the catabolic effect of LPS on skeletal muscle protein synthesis via alterations in protein-protein interactions within mTOR complex-1, and this may provide a survival advantage in response to bacterial infection.


2017 ◽  
Vol 313 (3) ◽  
pp. F805-F814 ◽  
Author(s):  
Takuya Yoshida ◽  
Sachika Kakizawa ◽  
Yuri Totsuka ◽  
Miho Sugimoto ◽  
Shinji Miura ◽  
...  

A low-protein diet (LPD) protects against the progression of renal injury in patients with chronic kidney disease (CKD). However, LPD may accelerate muscle wasting in these patients. Both exercise and branched-chain amino acids (BCAA) are known to increase muscle protein synthesis by activating the mammalian target of rapamycin (mTOR) pathway. The aim of this study was to investigate whether endurance exercise and BCAA play a role for increasing muscle protein synthesis in LPD-fed CKD (5/6 nephrectomized) rats. Both CKD and sham rats were pair-fed on LPD or LPD fortified with a BCAA diet (BD), and approximately one-half of the animals in each group was subjected to treadmill exercise (15 m/min, 1 h/day, 5 days/wk). After 7 wk, renal function was measured, and soleus muscles were collected to evaluate muscle protein synthesis. Renal function did not differ between LPD- and BD-fed CKD rats, and the treadmill exercise did not accelerate renal damage in either group. The treadmill exercise slightly increased the phosphorylation of p70s6 kinase, a marker of mTOR activity, in the soleus muscle of LPD-fed CKD rats compared with the sham group. Furthermore, BCAA supplementation of the LPD-fed, exercise-trained CKD rats restored the phosphorylation of p70s6 kinase to the same level observed in the sham group; however, the corresponding induced increase in muscle protein synthesis and muscle mass was marginal. These results indicate that the combination of treadmill exercise and BCAA stimulates cell signaling to promote muscle protein synthesis; however, the implications of this effect for muscle growth remain to be clarified.


Author(s):  
Floris C. Wardenaar ◽  
Ingrid J.M. Ceelen ◽  
Jan-Willem Van Dijk ◽  
Roland W.J. Hangelbroek ◽  
Lore Van Roy ◽  
...  

The use of nutritional supplements is highly prevalent among athletes. In this cross-sectional study, we assessed the prevalence of nutritional supplement use by a large group of Dutch competitive athletes in relation to dietary counseling. A total of 778 athletes (407 males and 371 females) completed a web-based questionnaire about the use of nutritional supplements. Log-binomial regression models were applied to estimate crude and adjusted prevalence ratios (PR) for the use of individual nutritional supplements in athletes receiving dietary counseling as compared with athletes not receiving dietary counseling. Of the athletes, 97.2% had used nutritional supplements at some time during their sports career, whereas 84.7% indicated having used supplements during the last 4 weeks. The top ranked supplements used over the last 4 weeks from dietary supplements, sport nutrition products and ergogenic supplements were multivitamin and mineral preparations (42.9%), isotonic sports drinks (44.1%) and caffeine (13.0%). After adjustment for elite status, age, and weekly exercise duration, dietary counseling was associated with a higher prevalence of the use of vitamin D, recovery drinks, energy bars, isotonic drinks with protein, dextrose, beta-alanine, and sodium bicarbonate. In contrast, dietary counseling was inversely associated with the use of combivitamins, calcium, vitamin E, vitamin B2, retinol, energy drinks and BCAA and other amino acids. In conclusion, almost all athletes had used nutritional supplements at some time during their athletic career. Receiving dietary counseling seemed to result in better-informed choices with respect to the use of nutritional supplements related to performance, recovery, and health.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Danielle T. Leahy ◽  
Stephen J. Pintauro

Supplementation with branched-chain amino acids (BCAAs) has been used to stimulate muscle protein synthesis following exercise. The purpose of this study was to determine if supplementation with BCAAs in combination with glucose would reduce exercise-induced delayed onset muscle soreness (DOMS). Using a double-blind crossover design, 20 subjects (11 females, 9 males) were randomly assigned to either BCAA () or placebo () groups. Subjects performed a squatting exercise to elicit DOMS and rated their muscle soreness every 24 hours for four days following exercise while continuing to consume the BCAA or placebo. Following a three-week recovery period, subjects returned and received the alternate BCAA or placebo treatment, repeating the same exercise and DOMS rating protocol for the next four days. BCAA supplementation in female subjects resulted in a significant decrease in DOMS versus placebo at 24 hours following exercise (). No significant effect of BCAA supplementation versus placebo was noted in male subjects nor when male and female results were analyzed together. This gender difference may be related to dose per body weight differences between male and female subjects.


Author(s):  
Jun Wang ◽  
Hongwei Guan ◽  
Morten Hostrup ◽  
David S. Rowlands ◽  
José González-Alonso ◽  
...  

AbstractBeijing will host the 2022 Winter Olympics, and China strengthens research on various aspects to allow their athletes to compete successfully in winter sport. Simultaneously, Government-directed initiatives aim to increase public participation in recreational winter sport. These parallel developments allow research to advance knowledge and understanding of the physiological determinants of performance and health related to winter sport. Winter sport athletes often conduct a substantial amount of training with high volumes of low-to-moderate exercise intensity and lower volumes of high-intensity work. Moreover, much of the training occur at low ambient temperatures and winter sport athletes have high risk of developing asthma or asthma-related conditions, such as exercise-induced bronchoconstriction. The high training volumes require optimal nutrition with increased energy and dietary protein requirement to stimulate muscle protein synthesis response in the post-exercise period. Whether higher protein intake is required in the cold should be investigated. Cross-country skiing is performed mostly in Northern hemisphere with a strong cultural heritage and sporting tradition. It is expected that innovative initiatives on recruitment and training during the next few years will target to enhance performance of Chinese athletes in classical endurance-based winter sport. The innovation potential coupled with resourcing and population may be substantial with the potential for China to become a significant winter sport nation. This paper discusses the physiological aspects of endurance training and performance in winter sport highlighting areas where innovation may advance in athletic performance in cold environments. In addition, to ensure sustainable development of snow sport, a quality ski patrol and rescue system is recommended for the safety of increasing mass participation.


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