Creatine supplementation in high school football players

Energy Expenditure, Dietary Energy Intake, and Nutritional Supplements in Adolescent Volleyball Athletes versus Nonathletic Controls

Evidence suggests that athletes competing in team sports do not follow dietary recommendations. However, only few studies have investigated energy needs and supplement use in adolescent athletes, and whether they are meeting their energy requirements. This observational study examined energy expenditure, dietary energy intake, and use of nutritional supplements in 58 adolescent (14-17 years old) volleyball athletes (15 males, 43 females) and 58 age-matched nonathletic controls (13 males, 45 females). Participants completed an online survey including questions on demographic information, body mass, and a series of standardized questionnaires assessing energy expenditure, dietary energy, macronutrient, micronutrient, and supplement intake. Energy expenditure relative to body mass was higher in athletes than nonathletes by 13 kcal/kg/day (group effect, p < 0.001), and in males compared to females by 5.7 kcal/kg/day (sex effect, p = 0.004). Athletes had higher energy intake than nonathletes (+6.4 kcal/kg/day, p = 0.019) and greater consumption of fruits (p = 0.034), vegetables (p = 0.047), grains (p = 0.016), dairy (p = 0.038), meats and meat alternatives (p < 0.001), as well as higher intakes of fat (p < 0.001), carbohydrates, protein, sugar, fiber, vitamin C, calcium, and sodium (p = 0.05) compared to nonathletes. The average protein intakes exceeded the upper recommendations in all groups, suggesting that this is not a nutrient of concern for young volleyball athletes. However, athletes were only meeting 60% of the estimated energy requirements (EER) for their age, height, body mass, and physical activity score, (3322 ± 520 kcal/day), while nonathletes were meeting 74% of the EER (p < 0.001). The relative energy balance of male athletes was lower compared to both female athletes (p = 0.006) and male nonathletes (p = 0.004). Finally, more athletes reported using performance-related supplements than nonathletes, but there were no differences in the consumption of other dietary supplements. Overall, when compared to nonathletic controls, both male and female adolescent volleyball athletes were found to match their higher energy expenditure with a greater dietary energy intake; however, all adolescents were below the estimated energy requirements, a finding more profound among the volleyball athletes.

Hesperidin Functions as an Ergogenic Aid by Increasing Endothelial Function and Decreasing Exercise-Induced Oxidative Stress and Inflammation, Thereby Contributing to Improved Exercise Performance

The regulation of blood flow to peripheral muscles is crucial for proper skeletal muscle functioning and exercise performance. During exercise, increased mitochondrial oxidative phosphorylation leads to increased electron leakage and consequently induces an increase in ROS formation, contributing to DNA, lipid, and protein damage. Moreover, exercise may increase blood- and intramuscular inflammatory factors leading to a deterioration in endurance performance. The aim of this review is to investigate the potential mechanisms through which the polyphenol hesperidin could lead to enhanced exercise performance, namely improved endothelial function, reduced exercise-induced oxidative stress, and inflammation. We selected in vivo RCTs, animal studies, and in vitro studies in which hesperidin, its aglycone form hesperetin, hesperetin-metabolites, or orange juice are supplemented at any dosage and where the parameters related to endothelial function, oxidative stress, and/or inflammation have been measured. The results collected in this review show that hesperidin improves endothelial function (via increased NO availability), inhibits ROS production, decreases production and plasma levels of pro-inflammatory markers, and improves anaerobic exercise outcomes (e.g., power, speed, energy). For elite and recreational athletes, hesperidin could be used as an ergogenic aid to enhance muscle recovery between training sessions, optimize oxygen and nutrient supplies to the muscles, and improve anaerobic performance.

The Role of Creatine in the Development and Activation of Immune Responses

The use of dietary supplements has become increasingly common over the past 20 years. Whereas supplements were formerly used mainly by elite athletes, age and fitness status no longer dictates who uses these substances. Indeed, many nutritional supplements are recommended by health care professionals to their patients. Creatine (CR) is a widely used dietary supplement that has been well-studied for its effects on performance and health. CR also aids in recovery from strenuous bouts of exercise by reducing inflammation. Although CR is considered to be very safe in recommended doses, a caveat is that a preponderance of the studies have focused upon young athletic individuals; thus there is limited knowledge regarding the effects of CR on children or the elderly. In this review, we examine the potential of CR to impact the host outside of the musculoskeletal system, specifically, the immune system, and discuss the available data demonstrating that CR can impact both innate and adaptive immune responses, together with how the effects on the immune system might be exploited to enhance human health.

International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine

Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Additionally, a number of clinical applications of creatine supplementation have been studied involving neurodegenerative diseases (e.g., muscular dystrophy, Parkinson's, Huntington's disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy. These studies provide a large body of evidence that creatine can not only improve exercise performance, but can play a role in preventing and/or reducing the severity of injury, enhancing rehabilitation from injuries, and helping athletes tolerate heavy training loads. Additionally, researchers have identified a number of potentially beneficial clinical uses of creatine supplementation. These studies show that short and long-term supplementation (up to 30 g/day for 5 years) is safe and well-tolerated in healthy individuals and in a number of patient populations ranging from infants to the elderly. Moreover, significant health benefits may be provided by ensuring habitual low dietary creatine ingestion (e.g., 3 g/day) throughout the lifespan. The purpose of this review is to provide an update to the current literature regarding the role and safety of creatine supplementation in exercise, sport, and medicine and to update the position stand of International Society of Sports Nutrition (ISSN).

Dietary Supplements and Young Teens: Misinformation and Access Provided by Retailers

BACKGROUND AND OBJECTIVE

Despite the American Academy of Pediatrics' recommendations against pediatric use of creatine and testosterone boosters, research suggests that many young teenagers take these dietary supplements. Our objective was to determine to what extent health food stores would recommend and/or sell creatine and testosterone boosters to a 15-year-old boy customer.

METHODS

Research personnel posing as 15-year-old high school athletes seeking to increase muscle strength contacted 244 health food stores in the United States via telephone. Researchers asked the sales attendant what supplements he/she would recommend. If a sales attendant did not mention creatine or testosterone boosters initially, each of these supplements was then specifically asked about. Supplement recommendations were recorded. Sales attendants were also asked if a 15-year-old could purchase these products on his own in the store.

RESULTS

A total of 67.2% (164/244) of sales attendants recommended creatine: 38.5% (94/244) recommended creatine without prompting, and an additional 28.7% (70/244) recommended creatine after being asked specifically about it. A total of 9.8% (24/244) of sales attendants recommended a testosterone booster. Regarding availability for sale, 74.2% (181/244) of sales attendants stated a 15-year-old was allowed to purchase creatine, whereas 41.4% (101/244) stated one could purchase a testosterone booster.

CONCLUSIONS

Health food store employees frequently recommend creatine and testosterone boosters for boy high school athletes. In response to these findings, pediatricians should inform their teenage patients, especially athletes, about safe, healthy methods to improve athletic performance and discourage them from using creatine or testosterone boosters. Retailers and state legislatures should also consider banning the sale of these products to minors.

Beyond muscles: The untapped potential of creatine

Creatine is widely used by both elite and recreational athletes as an ergogenic aid to enhance anaerobic exercise performance. Older individuals also use creatine to prevent sarcopenia and, accordingly, may have therapeutic benefits for muscle wasting diseases. Although the effect of creatine on the musculoskeletal system has been extensively studied, less attention has been paid to its potential effects on other physiological systems. Because there is a significant pool of creatine in the brain, the utility of creatine supplementation has been examined in vitro as well as in vivo in both animal models of neurological disorders and in humans. While the data are preliminary, there is evidence to suggest that individuals with certain neurological conditions may benefit from exogenous creatine supplementation if treatment protocols can be optimized. A small number of studies that have examined the impact of creatine on the immune system have shown an alteration in soluble mediator production and the expression of molecules involved in recognizing infections, specifically toll-like receptors. Future investigations evaluating the total impact of creatine supplementation are required to better understand the benefits and risks of creatine use, particularly since there is increasing evidence that creatine may have a regulatory impact on the immune system.

Caffeine and Progression of Parkinson Disease: A Deleterious Interaction With Creatine

OBJECTIVE

Increased caffeine intake is associated with a lower risk of Parkinson disease (PD) and is neuroprotective in mouse models of PD. However, in a previous study, an exploratory analysis suggested that, in patients taking creatine, caffeine intake was associated with a faster rate of progression. In the current study, we investigated the association of caffeine with the rate of progression of PD and the interaction of this association with creatine intake.

METHODS

Data were analyzed from a large phase 3 placebo-controlled clinical study of creatine as a potentially disease-modifying agent in PD. Subjects were recruited for this study from 45 movement disorders centers across the United States and Canada. A total of 1741 subjects with PD participated in the primary clinical study, and caffeine intake data were available for 1549 of these subjects. The association of caffeine intake with rate of progression of PD as measured by the change in the total Unified Parkinson Disease Rating Scale score and the interaction of this association with creatine intake were assessed.

RESULTS

Caffeine intake was not associated with the rate of progression of PD in the main analysis, but higher caffeine intake was associated with significantly faster progression among subjects taking creatine.

CONCLUSIONS

This is the largest and longest study conducted to date that addresses the association of caffeine with the rate of progression of PD. These data indicate a potentially deleterious interaction between caffeine and creatine with respect to the rate of progression of PD.

Nutritional supplements and ergogenic AIDS

Performance enhancing drugs, ergogenic aids, and supplements come in many forms. The financial, personal, social, and health-related impact of these substances has wide and varied consequences. This article reviews common substances and practices used by athletes. It discusses the history, use, effects, and adverse effects of androgenic anabolic steroids, peptide hormones, growth factors, masking agents, diuretics, volume expanders, β-blockers, amphetamines, caffeine, other stimulants, and creatine. The evidence base behind the use, safety, and efficacy of these items as well as testing for these substances is discussed.

The Physiological Effects of Creatine Supplementation on Hydration: A Review

In 1992, Harris and colleagues demonstrated that oral creatine supplementation can enhance muscle creatine stores. Since then, creatine has become an important and popular ergogenic aid for improving athletic performance with reports of up to 74% of athletes supplementing with creatine. Although many recent studies have addressed the safety concerns of creatine supplementation on hydration status in hot and humid environments, anecdotal reports still exist linking creatine usage to heat-related problems. These concerns are based on the premise that creatine is an osmotically active substance resulting in an alteration in fluid balance by increasing intracellular fluid volume and preventing fluid from entering the extracellular environment to aid in thermoregulation. However, a number studies have demonstrated that when recommended amounts of creatine are consumed, creatine does not appear to increase the risk of heat-related problems during exercise and may actually have a positive influence on core temperature and heart rate responses.

Performance-enhancing substances: is your adolescent patient using?

Small, but significant, numbers of adolescents use anabolic-androgenic steroids to improve their appearance or sports performance. Many more use creatine and other performance-enhancing substances with the hope of achieving these goals. This article assists primary care physicians in the office assessment of adolescents who may be using these substances, focusing on identifying adolescents at risk, asking the right questions, and helping adolescents feel comfortable discussing this sensitive topic. Providers must present themselves as credible sources of information on the topic to communicate effectively with adolescent athletes.

Creatine and other supplements

Ergogenic dietary supplement use is highly prevalent among adolescent and collegiate athletes, and use is increasing. To make appropriate recommendations for or against use by individual athletes, physicians who work with adolescent athletes should be knowledgeable about the most commonly used supplements and be able to access high-quality information about others. This article first discusses the legal and regulatory environment of dietary supplements. Several of the most commonly used supplements are then discussed in detail, including creatine, beta-hydroxy-beta-methylbutyrate, protein, amino acids, stimulants, alkalotic agents, glycerol, vitamins, and minerals. Finally, the "Gateway Theory" as it may relate to adolescent supplement and other drug use is discussed.

Sports medicine: performance-enhancing drugs

Performance-enhancing drugs, ergogenic aids, or sports supplements have been a part of sports since sporting competition began and likely always will be. Considered cheating by purists and necessary by some athletes, we must accept the fact that they are used, understand why they are used, and study how to prevent their use to institute change. This article summarizes current information regarding the use of performance-enhancing drugs in young athletes and provides proven prevention strategies for instituting a program in your local schools.

Prevalence of use of performance-enhancing substances among United States adolescents

Adolescents may regard the use of performance-enhancing substances as an easy means to gain self-esteem through improved body appearance and athletic performance. The use of performance-enhancing substances by adolescents is particularly troubling because safety data are largely lacking. This poses a dilemma for the pediatrician who needs correct information, including the potential efficacy and negative health effects of such substances, to identify the patients in need of counseling and to find the best way to help adolescent patients make informed decisions to promote healthy behaviors. This article is intended to assist pediatricians by providing a summary of the current state of knowledge regarding the prevalence of use of performance-enhancing substances by United States adolescents.

Medication and supplement use by athletes

Athletes are affected in various ways by medications and supplements. Physicians caring for athletes need to be aware of medicines that athletes are taking and how they may interact with performance, exercise, environment, and other medicines. Athletes may attempt to gain a performance advantage with the use of a variety of dietary supplements and performance enhancers. Physicians must be knowledgeable of these so that athletes are properly educated about potential benefits and risks and physical effects. This article first reviews common medicines that athletes use and their potential efficacy and interactions with exercise and environment, then reviews dietary supplements and the data on their efficacy for performance enhancement. Finally, current and future doping issues are discussed.

Exposure to the mass media, body shape concerns, and use of supplements to improve weight and shape among male and female adolescents

OBJECTIVE

To assess the prevalence and correlates of products used to improve weight and shape among male and female adolescents.

METHODS

A cross-sectional study was conducted of 6212 girls and 4237 boys who were 12 to 18 years of age and enrolled in the ongoing Growing Up Today Study. The outcome measure was at least weekly use of any of the following products to improve appearance, muscle mass, or strength: protein powder or shakes, creatine, amino acids/hydroxy methylbutyrate (HMB), dehydroepiandrosterone, growth hormone, or anabolic/injectable steroids.

RESULTS

Approximately 4.7% of the boys and 1.6% of the girls used protein powder or shakes, creatine, amino acids/HMB, dehydroepiandrosterone, growth hormone, or anabolic/injectable steroids at least weekly to improve appearance or strength. In multivariate models, boys and girls who thought a lot about wanting more defined muscles (boys: odds ratio [OR]: 1.6; 95% confidence interval [CI]: 1.1-2.2; girls: OR: 2.3; 95% CI: 1.2-3.2) or were trying to gain weight (boys: OR: 3.0; 95% CI: 2.0-4.6; girls: OR: 4.3; 95% CI: 1.6-11.4) were more likely than their peers to use these products. In addition, boys who read men's, fashion, or health/fitness magazines (OR: 2.3; 95% CI: 1.1-4.9) and girls who were trying to look like women in the media (OR: 2.9; 95% CI: 1.4-4.0) were significantly more likely than their peers to use products to improve appearance or strength, but hours per week watching television, watching sports on television, and participation in team sports were not independently associated with using products to improve appearance or muscle mass.

CONCLUSIONS

Girls and boys who frequently thought about wanting toned or well-defined muscles were at increased risk for using potentially unhealthful products to enhance their physique. These results suggest that just as girls may resort to unhealthful means to achieve a low body weight, girls and boys may also resort to unhealthful means to achieve other desired physiques.

Potential ergogenic effects of arginine and creatine supplementation

The rationale for the use of nutritional supplements to enhance exercise capacity is based on the assumption that they will confer an ergogenic effect above and beyond that afforded by regular food ingestion alone. The proposed or advertised ergogenic effect of many supplements is based on a presumptive metabolic pathway and may not necessarily translate to quantifiable changes in a variable as broadly defined as exercise performance. L-arginine is a conditionally essential amino acid that has received considerable attention due to potential effects on growth hormone secretion and nitric oxide production. In some clinical circumstances (e.g., burn injury, sepsis) in which the demand for arginine cannot be fully met by de novo synthesis and normal dietary intake, exogenous arginine has been shown to facilitate the maintenance of lean body mass and functional capacity. However, the evidence that supplemental arginine may also confer an ergogenic effect in normal healthy individuals is less compelling. In contrast to arginine, numerous studies have reported that supplementation with the arginine metabolite creatine facilitates an increase in anaerobic work capacity and muscle mass when accompanied by resistance training programs in both normal and patient populations. Whereas improvement in the rate of phosphocreatine resynthesis is largely responsible for improvements in acute work capacity, the direct effect of creatine supplementation on skeletal muscle protein synthesis is less clear. The purpose of this review is to summarize the role of arginine and its metabolite creatine in the context of a nutrition supplement for use in conjunction with an exercise stimulus in both healthy and patient populations.

Risk assessment of the potential side effects of long–term creatine supplementation in team sport athletes

BACKGROUND

Use of creatine has become widespread among sportsmen and women, although there are no conclusive evidences concerning possible health risks of long-term creatine supplementation.

THE AIM OF THE STUDY

To investigate long-term effects of creatine monohydrate supplementation on clinical parameters related to health.

METHODS

Eighteen professional basketball players of the first Spanish Basketball League participated in the present longitudinal study. The subjects were ingesting 5 g creatine monohydrate daily during three competition seasons. Blood was collected in the morning after an overnight fast, five times during each of the three official competition seasons of the first National Basketball League (September 1999-June 2000, September 2000-June 2001 and September 2001-June 2002) and the European League. Standard clinical examination was performed for 16 blood chemistries.

RESULTS

The plasma concentrations of all clinical parameters did not alter significantly during the analyzed time frames of creatine supplementation. All of these parameters were, with the exception of creatinine and creatine kinase, within their respective clinical ranges at all time points.

CONCLUSION

Our data shows that low-dose supplementation with creatine monohydrate did not produce laboratory abnormalities for the majority of the parameters tested.

Sports and performing arts medicine. 1. general considerations for sports and performing arts medicine11A commercial party with a direct financial interest in the results of the research supporting this article has conferred or will confer a financial benefit upon the author or one or more of the authors. Nadler is a consultant for Proctor & Gamble

This self-directed learning module highlights general considerations in sports and performing arts medicine. It is part of the study guide on sports and performing arts medicine in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation.

OVERALL ARTICLE OBJECTIVE

To discuss similarities and differences of injuries sustained in sports and performing arts using case vignettes.

Popular sports supplements and ergogenic aids

This article reviews the evidence-based ergogenic potential and adverse effects of 14 of the most common products in use by recreational and elite athletes today. Both legal and prohibited products are discussed. This is an aggressively marketed and controversial area of sports medicine worldwide. It is therefore prudent for the clinician to be well versed in the more popular supplements and drugs reputed to be ergogenic in order to distinguish fact from fiction.Antioxidants, proteins and amino acids are essential components of diet, but additional oral supplementation does not increase endurance or strength. Caffeine is ergogenic in certain aerobic activities. Creatine is ergogenic in repetitive anaerobic cycling sprints but not running or swimming. Ephedrine and pseudoephedrine may be ergogenic but have detrimental cardiovascular effects. Erythropoietin is ergogenic but increases the risk of thromboembolic events. beta-Hydroxy-beta-methylbutyrate has ergogenic potential in untrained individuals, but studies are needed on trained individuals. Human growth hormone and insulin growth factor-I decrease body fat and may increase lean muscle mass when given subcutaneously. Pyruvate is not ergogenic. The androgenic precursors androstenedione and dehydroepiandrosterone have not been shown to increase any parameters of strength and have potentially significant adverse effects. Anabolic steroids increase protein synthesis and muscle mass but with many adverse effects, some irreversible. Supplement claims on labels of product content and efficacy can be inaccurate and misleading.

Creatine supplementation and athletic performance

Nutritional supplements and other ergogenic aids have gained widespread use among professional, amateur, recreational, and student athletes for their potential to enhance athletic performance and provide a competitive edge. Creatine monohydrate is one of the more commonly used and potentially beneficial supplements that currently is viewed to be safe. Supplementation with oral creatine augments skeletal muscle creatine concentrations in most individuals, which has been shown to promote gains in lean body mass when used in conjunction with resistance training, to enhance power and strength, and to improve performance in intense exercise, especially during repeated bouts. Young athletes, however, must be cautious about taking creatine because its effects on growth and development are unknown and long-term safety has not been established. Variability in research study designs and small sample sizes have left many questions unanswered regarding the safety and efficacy of chronic supplementation. This is an active area of clinical investigation and the results of ongoing and future research should guide the appropriate use of creatine to enhance athletic performance among athletes of all ages.

Health implications of creatine: can oral creatine supplementation protect against neurological and atherosclerotic disease?

Major achievements made over the last several years have highlighted the important roles of creatine and the creatine kinase reaction in health and disease. Inborn errors of metabolism have been identified in the three main steps involved in creatine metabolism: arginine:glycine amidinotransferase (AGAT), S-adenosyl-L-methionine:N-guanidinoacetate methyltransferase (GAMT), and the creatine transporter. All these diseases are characterized by a lack of creatine and phosphorylcreatine in the brain, and by (severe) mental retardation. Similarly, knockout mice lacking the brain cytosolic and mitochondrial isoenzymes of creatine kinase displayed a slightly increased creatine concentration, but no phosphorylcreatine in the brain. These mice revealed decreased weight gain and reduced life expectancy, disturbed fat metabolism, behavioral abnormalities and impaired learning capacity. Oral creatine supplementation improved the clinical symptoms in both AGAT and GAMT deficiency, but not in creatine transporter deficiency. In addition, creatine supplementation displayed neuroprotective effects in several animal models of neurological disease, such as Huntington's disease, Parkinson's disease, or amyotrophic lateral sclerosis. All these findings pinpoint to a close correlation between the functional capacity of the creatine kinase/phosphorylcreatine/creatine system and proper brain function. They also offer a starting-point for novel means of delaying neurodegenerative disease, and/or for strengthening memory function and intellectual capabilities.Finally, creatine biosynthesis has been postulated as a major effector of homocysteine concentration in the plasma, which has been identified as an independent graded risk factor for atherosclerotic disease. By decreasing homocysteine production, oral creatine supplementation may, thus, also lower the risk for developing, e.g., coronary heart disease or cerebrovascular disease. Although compelling, these results require further confirmation in clinical studies in humans, together with a thorough evaluation of the safety of oral creatine supplementation.