Adverse effects of creatine supplementation: fact or fiction?

Exploring the relationship between creatine supplementation and renal function: insights from Mendelian randomization analysis

BACKGROUND

Creatine supplementation is ubiquitously consumed by fitness enthusiasts due to its perceived advantages in enhancing athletic performance. Although there is an increasing concern within this demographic regarding its possible impact on renal function, there is still a lack of rigorous scientific investigations into this alleged association.

METHODS

Data were collected through an online survey on the participants' demographics, creatine usage and concerns related to renal function. The reliability and validity of the survey were assessed using SPSS software. A total of 1129 participants responded to the survey, and chi-square tests were utilized for data analysis. To explore the potential association between creatine levels (as the exposure) and renal function (as the outcome), we utilized open-access genetic databases, and Mendelian randomization (MR) techniques were used to confirm this correlation.

RESULTS

Chi-square analysis revealed no significant association between creatine usage and renal function among the participants. Our MR analysis further supported this finding, demonstrating no significant association between creatine levels and six indicators assessing renal function (IVW, all with p values exceeding 0.05). Similar p values were consistently observed across other MR methods, confirming the absence of a statistical correlation.

CONCLUSIONS

This MR study offers compelling evidence indicating that creatine levels are not statistically associated with renal function, suggesting the potential to alleviate concerns within the fitness community and emphasizing the significance of evidence-based decision-making when considering nutritional supplementation.

Fast and simple analysis of the content of Zn, Mg, Ca, Na, and K in selected beverages widely consumed by athletes by flowing liquid cathode atmospheric pressure glow discharge optical emission spectrometry

An atmospheric pressure glow discharge (APGD) system, generated between a flowing liquid cathode (FLC) and a gas (He) jet anode, was applied for the determination of Zn, Mg, Ca, Na, and K in selected beverages commonly chosen by athletes (namely Coca-Cola Zero, energy and vitamin drinks, pre-workout, branched-chain amino acids, almond drink, and whey protein) by optical emission spectrometry (OES). In some cases (i.e., Coca-Cola, energy drink, and almond drink), sugared and sugar-free versions of the beverages were analyzed with the purpose of establishing the impact of added sugar on the analyte signal intensities. The analysis was performed after a simplified sample preparation procedure, which involved only their dilution and acidification with HNO₃ to a concentration of 0.2 mol L^-1. To determine the most suitable conditions for performing the analysis, optimization of the crucial operating parameters and sample dilution was carried out. Under the compromise conditions, the instrumental detection limits (DLs) were established and found to be 21, 0.91, 20, 0.062, and 0.14 μg L^-1 for Zn, Mg, Ca, Na, and K, respectively. Due to the relatively low detection limits, the analyte content could be determined for a fairly high dilution, being concurrently the same for all analytes, which further simplified the whole procedure. It was found that the vast majority of samples could be determined using external calibration with simple standard solutions. The standard addition technique used for calibration was only required for the determination of Mg in three samples. The analysis results were consistent (in the majority of cases the recovery values were in the range of 88-111%) with the values obtained for the reference method (inductively coupled plasma optical emission spectrometry, ICP-OES), which proved the reliability of the results obtained from the developed FLC-APGD-OES system.

Creatine supplementation in the pediatric and adolescent athlete-- A literature review

Background

An increase in intra-muscular creatine through supplementation has been proposed as a strategy for improving muscle performance and recovery, with studies showing some benefit for adult athletes who rely on short, explosive movements. We reviewed and summarized the current literature on creatine supplementation in a pediatric and adolescent population.

Methods

The databases PubMed and EMBASE were queried to identity articles related to the use of creatine supplementation in a healthy pediatric and adolescent population according to the guidelines established by PRISMA. The abstracts of all articles were reviewed to determine relevancy, with those meeting the pre-defined criteria included in the final review.

Results

A combined total of 9393 articles were identified. Following application of filters and review of abstracts, 13 articles were found to meet criteria and were included in the final review. There was a total of 268 subjects across all studies, with mean age ranging from 11.5 to 18.2 years. More than 75% of the studies were randomized-controlled trials, and 85% involved either soccer players or swimmers. The overall quality of the studies was poor, and there were no consistent findings regarding creatine supplementation and improvements in athletic performance. No studies were designed to address the topic of safety.

Conclusions

There is a gap in the study of the safety and efficacy of creatine supplementation in adolescents. Additional studies are needed to evaluate the effects of alterations in muscle composition on the growth, development, and performance of the developing athlete. Orthopedic providers should counsel their pediatric and adolescent patients on the current limitations in trying to assess the true risk and benefit of creatine supplementation for the aspiring athlete.

Level of evidence

Review, III.

Proteome network analysis of skeletal muscle in lignan-enriched nutmeg extract-fed aged mice

Sarcopenia, characterized by reduced muscle mass and fiber number leading to muscular atrophy, has been associated with serious socioeconomic challenges among the elderly in developed countries. Therefore, preventing sarcopenia could be a promising strategy for achieving a healthy aging society. Nutmeg (Myristica fragrans) has been used as a spice to increase flavor and prevent putrefaction of food. Nutmeg contains various bioactive components that improve muscle activity. To determine the potential effect of lignan-enriched nutmeg extract (LNX) on sarcopenia, LNX (100 mg/kg body weight)-fed aged mice were subjected to forced exercise. Herein, aged (22-month-old) mice fed LNX for three weeks exhibited a shortened and thickened soleus muscle. The ratio of the soleus muscle mass (%) to body weight was significantly increased in LNX-fed aged mice. The relative increase in muscle mass in LNX-fed aged mice improved exercise activities, including rotarod, swimming, and grip strength test results. Proteome profiles of the soleus muscle of LNX-fed mice were used to analyze protein–protein interaction network. Several myosin heavy chain isoforms were found to interact with actin, ACTA1, which functions as a hub protein. Furthermore, the expression of myogenic proteins, such as MYH1, MYH4, and ACTA1, was dose-dependently increased in vivo. In result, our functional proteomic analysis revealed that feeding LNX restored muscle proteins in aged mice.

The Dietary Supplement Creatyl-l-Leucine Does Not Bioaccumulate in Muscle, Brain or Plasma and Is Not a Significant Bioavailable Source of Creatine

Creatine is an important energy metabolite that is concentrated in tissues such as the muscles and brain. Creatine is reversibly converted to creatine phosphate through a reaction with ATP or ADP, which is catalyzed by the enzyme creatine kinase. Dietary supplementation with relatively large amounts of creatine monohydrate has been proven as an effective sports supplement that can enhances athletic performance during acute high-energy demand physical activity. Some side effects have been reported with creatine monohydrate supplementation, which have stimulated research into new potential molecules that could be used as supplements to potentially provide bioavailable creatine. Recently, a popular supplement, creatyl-l-leucine, has been proposed as a potential dietary ingredient that may potentially provide bioavailable creatine. This study tests whether creatyl-l-leucine is a bioavailable compound and determines whether it can furnish creatine as a dietary supplement. Rats were deprived of dietary creatine for a period of two weeks and then given one of three treatments: a control AIN-93G creatine-free diet, AIN-93G supplemented with creatine monohydrate or AIN-93G with an equimolar amount of creatyl-l-leucine supplement in the diet for one week. When compared to the control and the creatine monohydrate-supplemented diet, creatyl-l-leucine supplementation resulted in no bioaccumulation of either creatyl-l-leucine or creatine in tissue.

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.

Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?

Supplementing with creatine is very popular amongst athletes and exercising individuals for improving muscle mass, performance and recovery. Accumulating evidence also suggests that creatine supplementation produces a variety of beneficial effects in older and patient populations. Furthermore, evidence-based research shows that creatine supplementation is relatively well tolerated, especially at recommended dosages (i.e. 3-5 g/day or 0.1 g/kg of body mass/day). Although there are over 500 peer-refereed publications involving creatine supplementation, it is somewhat surprising that questions regarding the efficacy and safety of creatine still remain. These include, but are not limited to: 1. Does creatine lead to water retention? 2. Is creatine an anabolic steroid? 3. Does creatine cause kidney damage/renal dysfunction? 4. Does creatine cause hair loss / baldness? 5. Does creatine lead to dehydration and muscle cramping? 6. Is creatine harmful for children and adolescents? 7. Does creatine increase fat mass? 8. Is a creatine 'loading-phase' required? 9. Is creatine beneficial for older adults? 10. Is creatine only useful for resistance / power type activities? 11. Is creatine only effective for males? 12. Are other forms of creatine similar or superior to monohydrate and is creatine stable in solutions/beverages? To answer these questions, an internationally renowned team of research experts was formed to perform an evidence-based scientific evaluation of the literature regarding creatine supplementation.

Risk of Adverse Outcomes in Females Taking Oral Creatine Monohydrate: A Systematic Review and Meta-Analysis

Creatine Monohydrate (CrM) is a dietary supplement routinely used as an ergogenic aid for sport and training, and as a potential therapeutic aid to augment different disease processes. Despite its increased use in recent years, studies reporting potential adverse outcomes of CrM have been mostly derived from male or mixed sex populations. A systematic search was conducted, which included female participants on CrM, where adverse outcomes were reported, with meta-analysis performed where appropriate. Six hundred and fifty-six studies were identified where creatine supplementation was the primary intervention; fifty-eight were female only studies (9%). Twenty-nine studies monitored for adverse outcomes, with 951 participants. There were no deaths or serious adverse outcomes reported. There were no significant differences in total adverse events, (risk ratio (RR) 1.24 (95% CI 0.51, 2.98)), gastrointestinal events, (RR 1.09 (95% CI 0.53, 2.24)), or weight gain, (mean difference (MD) 1.24 kg pre-intervention, (95% CI -0.34, 2.82)) to 1.37 kg post-intervention (95% CI -0.50, 3.23)), in CrM supplemented females, when stratified by dosing regimen and subject to meta-analysis. No statistically significant difference was reported in measures of renal or hepatic function. In conclusion, mortality and serious adverse events are not associated with CrM supplementation in females. Nor does the use of creatine supplementation increase the risk of total adverse outcomes, weight gain or renal and hepatic complications in females. However, all future studies of creatine supplementation in females should consider surveillance and comprehensive reporting of adverse outcomes to better inform participants and health professionals involved in future trials.

Beyond sports: Efficacy and safety of creatine supplementation in pathological or paraphysiological conditions of brain and muscle

Creatine is pivotal in energy metabolism of muscle and brain cells, both in physiological and in pathological conditions. Additionally, creatine facilitates the differentiation of muscle and neuronal cells. Evidence of effectiveness of creatine supplementation in improving several clinical conditions is now substantial, and we review it in this paper. In hereditary diseases where its synthesis is impaired, creatine has a disease-modifying capacity, especially when started soon after birth. Strong evidence, including a Cochrane meta-analysis, shows that it improves muscular strength and general well-being in muscular dystrophies. Significant evidence exists also of its effectiveness in secondary prevention of statin myopathy and of treatment-resistant depression in women. Vegetarians and vegans do not consume any dietary creatine and must synthesize all they need, spending most of their methylation capacity. Nevertheless, they have a lower muscular concentration of creatine. Creatine supplementation has proved effective in increasing muscular and neuropsychological performance in vegetarians or vegans and should, therefore, be recommended especially in those of them who are athletes, heavy-duty laborers or who undergo intense mental effort. Convincing evidence also exists of creatine effectiveness in muscular atrophy and sarcopenia in the elderly, and in brain energy shortage (mental fatigue, sleep deprivation, environmental hypoxia as in mountain climbing, and advanced age). Furthermore, we review more randomized, placebo-controlled trials showing that creatine supplementation is safe up to 20 g/d, with a possible caveat only in people with kidney disease. We trust that the evidence we review will be translated into clinical practice and will spur more research on these subjects.

Effects of dietary supplements on selected hematological and biochemical parameters of Pakistani athletes

Background

CDC’s (Centers for Disease Control and Prevention) National Center for Health statistics recent reports have shown that an upsurge has occurred in the use of dietary supplements among age of 20 years since 1994 and this use shown regular increase. The purpose of our study was to investigate the effect of supplements on the reproductive health on male athletes in Pakistan.

Methods

A total of 150 adult male with mean age of 25.78 ± 0.56 years were included in this study and divided into four groups: Non-athlete control (n = 57), Non supplemental athlete control (n = 40), Supplemental athlete group I (n = 28) and supplemental athlete group II (n = 25). Blood (10 ml) was taken from each subject. Complete blood count was performed and 5 ml of blood was centrifuged to separate plasma and then analyzed for antioxidant enzyme (CAT, POD, GR and GSH) activities, Lipid peroxidation (TBARS), electrolyte, metal (sodium, potassium and zinc) and Luteinizing hormone (LH) concentration.

Results

Complete blood count results showed normal RBC, WBC, Platelets, Hemoglobin, Hematocrit, Mean corpuscular hemoglobin and Mean corpuscular hemoglobin concentration. Antioxidant enzymes (CAT, POD, GR, GSH) increased significantly in supplemental athletes as compared to control groups. Sodium and potassium showed significant increase (p < 0.001) in supplemental athlete group I, while TBARS also showed significant increase (p < 0.05) in supplemental group I and II as compared to non athlete control while non supplemental athletes showed significant increase (p < 0.05) in TBARS concentration as compared to non athlete control. LH concentration was found to be decreased significantly (p < 0.05) in supplemental group I and II as compared to control groups.

Conclusion

It is therefore concluded from the present results that oxidative stress was considerably elevated in response to supplement consumption among athletes which may affect their health haematological parameters and reproductive hormones.

A Toxicological Assessment of Creatyl-l-Leucine

A battery of toxicological studies was conducted to investigate the genotoxicity and repeated-dose oral toxicity of creatyl-l-leucine, a synthetic compound, in rats in accordance with internationally accepted guidelines. There was no evidence of mutagenicity in a bacterial reverse mutation test and in an in vitro mammalian chromosomal aberration test. There was no genotoxic activity observed in an in vivo mammalian micronucleus test at concentrations up to the limit dose of 2,000 mg/kg bw/d. Creatyl-l-leucine did not cause mortality or toxic effects in Hsd.Han Wistar rats in a 90-day repeated-dose oral (gavage) toxicity study at doses of 1,250, 2,500, and 5,000 mg/kg bw/d. The no observed adverse effect level from the 90-day study was determined to be 5,000 mg/kg bw/d, the highest dose tested, for both male and female rats.

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).

Effect of low dose, short-term creatine supplementation on muscle power output in elite youth soccer players

Background

To determine the effects of a low dose, short-term Creatine monohydrate (Cr) supplementation (0.03 g.kg.d⁻¹ during 14 d) on muscle power output in elite youth soccer players.

Methods

Using a two-group matched, double blind, placebo-controlled design, nineteen male soccer players (mean age = 17.0 ± 0.5 years) were randomly assigned to either Cr (N = 9) or placebo (N = 10) group. Before and after supplementation, participants performed a 30s Wingate Anaerobic Test (WAnT) to assess peak power output (PPO), mean power output (MPO), fatigue index (FI), and total work.

Results

There were significant increases in both PPO and MPO after the Cr supplementation period (P ≤ 0.05) but not the placebo period. There were also significant increases in total work, but not FI, after the Cr supplementation and placebo periods (P ≤ 0.05). Notably, there were differences in total work between the Cr and placebo groups after (P ≤ 0.05) but not before the 14 d supplementation period.

Conclusion

There is substantial evidence to indicate that a low-dose, short-term oral Cr supplementation beneficially affected muscle power output in elite youth soccer players.

Timing, Optimal Dose and Intake Duration of Dietary Supplements with Evidence-Based Use in Sports Nutrition

[Purpose]

The aim of the present narrative review was to consider the evidence on the timing, optimal dose and intake duration of the main dietary supplements in sports nutrition, i.e. β-alanine, nitrate, caffeine, creatine, sodium bicarbonate, carbohydrate and protein.

[Methods]

This review article focuses on timing, optimal dose and intake duration of main dietary supplements in sports nutrition.

[Results]

This paper reviewed the evidence to determine the optimal time, efficacy doses and intake duration for sports supplements verified by scientific evidence that report a performance enhancing effect in both situation of laboratory and training settings.

[Conclusion]

Consumption of the supplements are usually suggested into 5 specific times, such as pre-exercise (nitrate, caffeine, sodium bicarbonate, carbohydrate and protein), during exercise (carbohydrate), post-exercise (creatine, carbohydrate, protein), meal time (β-alanine, creatine, sodium bicarbonate, nitrate, carbohydrate and protein), and before sleep (protein). In addition, the recommended dosing protocol for the supplements nitrate and β-alanine are fixed amounts irrespective of body weight, while dosing protocol for sodium bicarbonate, caffeine and creatine supplements are related to corrected body weight (mg/kg bw). Also, intake duration is suggested for creatine and β-alanine, being effective in chronic daily time < 2 weeks while caffeine, sodium bicarbonate are effective in acute daily time (1-3 hours). Plus, ingestion of nitrate supplement is required in both chronic daily time < 28 days and acute daily time (2- 2.5 h) prior exercise.

[Prevention and treatment of energy failure in neonates with hypoxic-ischemic encephalopathy]

Hypoxic-ischemic encephalopathy (HIE) in neonates is the brain injury caused by perinatal asphyxia or hypoxia and is a major cause of death in neonates and nervous system dysfunction in infants and young children. Although to a certain degree, mild hypothermia therapy reduces the mortality of infants with moderate to severe HIE, it cannot achieve the expected improvements in nervous system dysfunction. Hence, it is of vital importance to search for effective therapeutic methods for HIE. The search for more therapies and better preventive measures based on the pathogenesis of HIE has resulted in much research. As an important link in the course of HIE, energy failure greatly affects the development and progression of HIE. This article reviews the research advances in the treatment and prevention of energy failure in the course of HIE.

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.

Health Risks of Selected Performance-Enhancing Drugs

This article reviews adverse effects of and the difficulty of attributing toxic effects to selected drugs and dietary supplements that purportedly enhance athletic performance. On surveys estimating the extent of performance-enhancing drug use, 5% of high school students indicated anabolic-adrenergic steroid use, and approximately 28% of collegiate athletes and 5.6% of middle and high school athletes admitted creatine use. Many adverse health effects from the abuse of androgenic-anabolic steroids and androstenedione (a prodrug) are exaggerations of excessive testosterone on hepatic, cardiovascular, reproductive, and behavioral functions that can produce permanent changes. With creatine use, nausea, vomiting, diarrhea, elevated serum transaminase concentrations, hypertension, fluid retention, muscle cramping, and muscle strains have been reported. Ephedra stimulates adrenergic receptors, leading to tachycardia and hypertension, with central nervous system effects of anxiety, tremor, and hyperactivity. From 1997 to 1999, 10 people died and 13 suffered permanent disabilities due to ephedra. γ -Hydroxybutyrate and several prodrugs (γ -butyrolactone and 1,4-butanediol) can produce alternating agitation and coma, amnesia, hypotonia, ataxia, nystagmus, tremors, bradycardia, respiratory depression, and apnea. Although γ -hydroxybutyrate abuse began as a bodybuilding aid, most serious adverse effects are from acute overdoses. Adverse effects from performance-enhancing drugs do occur, but their extent and frequency are unknown.

Effects of acute and chronic hypohydration on kidney health and function

The kidneys play a critical role in the homeostasis of body fluid tonicity and effective circulating volume. Renal homeostatic mechanisms are frequently challenged in acutely ill people. Fluid depletion causing hypovolemia may result in renal hypoperfusion that, if left untreated, may lead to acute kidney failure. Some populations, notably older people and neonates, are less tolerant of extremes in fluid loading and deprivation, similar to those with established chronic kidney disease. Risk of kidney injury during fluid depletion is increased by medications including diuretics, nonsteroidal antiinflammatory drugs, and renin-angiotensin system blockers. There is no consistent evidence indicating that lower-than-average fluid intake can cause chronic kidney disease, nor accelerate progression of established kidney disease. Increasing consumption of sugar-containing beverages is, however, a major concern for kidney health as a precursor of obesity and diabetes. There is no evidence that high dietary protein intake can cause chronic kidney disease, nor accelerate progression of established kidney disease. Idiosyncratic, adverse renal responses have been described with creatine supplements. There are only a few clinical conditions for which high fluid intake should be considered. These include recurrent kidney stones or urinary tract infections and, possibly, polycystic kidney disease.

Effect of taking dietary supplement on hematological and biochemical parameters in male bodybuilders an equation model

Background:

The improved physical action following administration of supplements to bodybuilders was supported by changes in laboratory parameters. Despite the fact that these supplements are sometimes associated both advantage and side effects, this study were conducted for the purpose of evaluating the possible effects of some commonly used supplements in bodybuilders on the hematological and biochemical parameters.

Materials and Methods:

In this study, we included 40 male bodybuilders as cases and 40 controls in the age group of 20-40 years. They used different kinds of supplements for 1 year. In general, all the supplements used were classified into two groups: hormonal and non-hormonal. Laboratory tests were requested for evaluation of hematological and biochemical parameters.

Results:

In an equation model, we found that weight (P = 0.024), duration of bodybuilding (P < 0.001), and duration of hormone supplement consumption (P < 0.001) were loaded significantly on the latent variables, demographic and dietary supplement, respectively. The relationship between dietary supplement and biochemical and hematological parameters was significant (P = 0.01) and some of these parameters including creatinine (P = 0.023), blood aspartate aminotransferase (AST) (P < 0.001), alanine aminotransferase (ALT) (P < 0.001), and red blood cell distribution (RDW) (P = 0.046) had a significant role than others. In a multivariate regression model, we found that WBC (P < 0.001), platelets (P < 0.001), blood urea nitrogen (BUN; P < 0.001), creatinine (P < 0.001), AST (P = 0.005), and ALT (P = 0.001) were higher in athletes than in controls.

Conclusions:

It is strongly advised that there should be some concerns about possible supplement-induced changes in the laboratory exams for bodybuilders. The available supplements are unchecked and not approved by the US Food and Drug Administration (FDA). More studies should be designed for a better and precise administration of each supplement in athletes.

Creatine for neuroprotection in neurodegenerative disease: end of story?

Creatine (Cr) is a natural compound that plays an important role in cellular energy homeostasis. In addition, it ameliorates oxidative stress, glutamatergic excitotoxicity, and apoptosis in vitro as well as in vivo. Since these pathomechanisms are implicated to play a role in several neurodegenerative diseases, Cr supplementation as a neuroprotective strategy has received a lot of attention with several positive animal studies in models of Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). This has led to a number of randomized clinical trials (RCT) with oral Cr supplementation, with durations up to 5 years. In this paper, we review the evidence and consequences stemming from these trials. In the case of PD, the initial phase II RCT was promising and led to a large and well-designed phase III trial, which, however, turned out to be negative for all outcome measures. None of the RCTs that have examined effects of Cr in ALS patients showed any clinical benefit. In HD, Cr in high doses (up to 30 g/day) was shown to slow down brain atrophy in premanifest Huntingtin mutation carriers. In spite of this, proof is still lacking that Cr can also have beneficial clinical effects in this group of patients, who will go on to develop HD symptoms. Taken together, the use of Cr supplementation has so far proved disappointing in clinical studies with a number of symptomatic neurodegenerative diseases.

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.

Dietary interventions designed to protect the perinatal brain from hypoxic-ischemic encephalopathy--Creatine prophylaxis and the need for multi-organ protection

Birth asphyxia or hypoxia arises from impaired placental gas exchange during labor and remains one of the leading causes of neonatal morbidity and mortality worldwide. It is a condition that can strike in pregnancies that have been uneventful until these final moments, and leads to fundamental loss of cellular energy reserves in the newborn. The cascade of metabolic changes that occurs in the brain at birth as a result of hypoxia can lead to significant damage that evolves over several hours and days, the severity of which can be ameliorated with therapeutic cerebral hypothermia. However, this treatment is only applied to a subset of newborns that meet strict inclusion criteria and is usually administered only in facilities with a high level of medical surveillance. Hence, a number of neuropharmacological interventions have been suggested as adjunct therapies to improve the efficacy of hypothermia, which alone improves survival of the post-hypoxic infant but does not altogether prevent adverse neurological outcomes. In this review we discuss the prospect of using creatine as a dietary supplement during pregnancy and nutritional intervention that can significantly decrease the risk of brain damage in the event of severe oxygen deprivation at birth. Because brain damage can also arise secondarily to compromise of other fetal organs (e.g., heart, diaphragm, kidney), and that compromise of mitochondrial function under hypoxic conditions may be a common mechanism leading to damage of these tissues, we present data suggesting that dietary creatine supplementation during pregnancy may be an effective prophylaxis that can protect the fetus from the multi-organ consequences of severe hypoxia at birth.

Effects of long-term low-dose dietary creatine supplementation in older women

OBJECTIVE

We aimed to investigate the effects of a one-year low-dose creatine supplementation trial on bone health, lean mass, and muscle function in older postmenopausal women.

METHODS

A double-blind, randomized, parallel-group, placebo controlled trial was conducted between November 2011 and November 2013 in Sao Paulo, Brazil. Postmenopausal osteopenic women were randomly allocated (1:1) into creatine (n=56; 1g/d) or placebo group (n=53; dextrose at same dose). At baseline and after one year of intervention, we assessed parameters of bone health, body composition, and muscle function. Blood parameters were also assessed before and after the intervention and adverse events were recorded throughout the trial. Possible differences in dietary intake were assessed by three 24-h dietary recalls.

RESULTS

Bone mineral density at lumbar spine, femoral neck, total femur, and whole body did not differ within- or between-groups. No significant changes in body weight, BMI, absolute and relative body fat, and body lean mass were observed. Muscle function, as assessed by timed-up-and-go and timed-stands tests, were not significantly changed within- or between-groups. Safety laboratory parameters remained unaltered.

CONCLUSION

A one-year low-dose creatine supplementation (1g/d) was free of adverse effects, but did not affect bone health parameters, lean mass, or muscle function in older women. Further studies with longer follow-up periods and higher doses of creatine supplementation are warranted. (Registered at clinicaltrials.gov as NCT01472393).

Effects of dietary creatine supplementation on systemic microvascular density and reactivity in healthy young adults

Background

Dietary creatine supplementation (CrS) is a practice commonly adopted by physically active individuals. However, the effects of CrS on systemic microvascular reactivity and density have never been reported. Additionally, CrS is able to influence blood levels of homocysteine, resulting in presumed effects on vascular endothelial function. Thus, we investigated the effects of CrS on the systemic microcirculation and on homocysteine levels in healthy young individuals.

Methods

This open-label study was performed on a group of 40 healthy male, moderately physically active subjects aged 27.7 ± 13.4 years who received one week of CrS at a dose of 20 g/day of commercially available micronized creatine monohydrate. Laser speckle contrast imaging was used in the evaluation of cutaneous microvascular reactivity, and intra-vital video microscopy was used to evaluate skin capillary density and reactivity, before and after CrS.

Results

CrS did not alter plasma levels of homocysteine, although CrS increased creatinine (p = 0.0001) and decreased uric acid (p = 0.0004) plasma levels. Significant changes in total cholesterol (p = 0.0486) and LDL-cholesterol (p = 0.0027) were also observed along with a reduction in plasma levels of T3 (p = 0.0074) and an increase in T4 levels (p = 0.0003). Skin functional capillary density (p = 0.0496) and capillary recruitment during post-occlusive reactive hyperemia (p = 0.0043) increased after CrS. Increases in cutaneous microvascular vasodilation induced by post-occlusive reactive hyperemia (p = 0.0078) were also observed.

Conclusions

Oral supplementation with creatine in healthy, moderately physically active young adults improves systemic endothelial-dependent microvascular reactivity and increases skin capillary density and recruitment. These effects are not concurrent with changes in plasma homocysteine levels.

Ingesting a preworkout supplement containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days is both safe and efficacious in recreationally active men

The purpose of this study was to determine the safety and efficacy of consuming a preworkout supplement (SUP) containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days. We hypothesized that little to no changes in kidney and liver clinical blood markers or resting heart rate and blood pressure (BP) would be observed. In addition, we hypothesized that body composition and performance would improve in recreationally active males after 28 days of supplementation. In a double-blind, placebo-controlled study, participants were randomly assigned to ingest one scoop of either the SUP or placebo every day for 28 days, either 20 minutes before exercise or ad libitum on nonexercise days. Resting heart rate and BP, body composition, and fasting blood samples were collected before and after supplementation. Aerobic capacity as well as muscular strength and endurance were also measured. Significant (P < .05) main effects for time were observed for resting heart rate (presupplementation, 67.59 ± 7.90 beats per minute; postsupplementation, 66.18 ± 7.63 beats per minute), systolic BP (presupplementation, 122.41 ± 11.25 mm Hg; postsupplementation, 118.35 ± 11.58 mm Hg), blood urea nitrogen (presupplementation, 13.12 ± 2.55 mg/dL; postsupplementation, 15.24 ± 4.47 mg/dL), aspartate aminotransferase (presupplementation, 34.29 ± 16.48 IU/L; postsupplementation, 24.76 ± 4.71 IU/L), and alanine aminotransferase (presupplementation, 32.76 ± 19.72 IU/L; postsupplementation, 24.88 ± 9.68 IU/L). Significant main effects for time were observed for body fat percentage (presupplementation, 15.55% ± 5.79%; postsupplementation, 14.21% ± 5.38%; P = .004) and fat-free mass (presupplementation, 70.80 ± 9.21 kg; postsupplementation, 71.98 ± 9.27 kg; P = .006). A significant decrease in maximal oxygen consumption (presupplementation, 47.28 ± 2.69 mL/kg per minute; postsupplementation, 45.60 ± 2.81 mL/kg per minute) and a significant increase in percentage of oxygen consumption per unit time at which ventilatory threshold occurred (presupplementation, 64.38% ± 6.63%; postsupplementation, 70.63% ± 6.39%) and leg press one-repetition maximum (presupplementation, 218.75 ± 38.43 kg; postsupplementation, 228.75 ± 44.79 kg) were observed in the SUP only. No adverse effects were noted for renal and hepatic clinical blood markers, resting heart rate, or BP. Supplements containing similar ingredients and doses should be safe for ingestion periods lasting up to 28 days in healthy, recreationally trained, college-aged men.

Creatine for treating muscle disorders

BACKGROUND

Progressive muscle weakness is a main symptom of most hereditary and acquired muscle diseases. Creatine improves muscle performance in healthy individuals. This is an update of our 2007 Cochrane review that evaluated creatine treatment in muscle disorders. Previous updates were in 2009 and 2011.

OBJECTIVES

To evaluate the efficacy of creatine compared to placebo for the treatment of muscle weakness in muscle diseases.

SEARCH METHODS

On 11 September 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (2012, Issue 9 in The Cochrane Library), MEDLINE (January 1966 to September 2012) and EMBASE (January 1980 to September 2012) for randomised controlled trials (RCTs) of creatine used to treat muscle diseases.

SELECTION CRITERIA

RCTs or quasi-RCTs of creatine treatment compared to placebo in hereditary muscle diseases or idiopathic inflammatory myopathies.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the selection criteria, assessed trial quality and extracted data. We obtained missing data from investigators.

MAIN RESULTS

A total of 14 trials, including 364 randomised participants, met the selection criteria. The risk of bias was low in most studies. Only one trial had a high risk of selection, performance and detection bias. No new studies were identified at this update.Meta-analysis of six trials in muscular dystrophies including 192 participants revealed a significant increase in muscle strength in the creatine group compared to placebo, with a mean difference of 8.47%; (95% confidence intervals (CI) 3.55 to 13.38). Pooled data of four trials including 115 participants showed that a significantly higher number of participants felt better during creatine treatment compared to placebo with a risk ratio of 4.51 (95% CI 2.33 to 8.74). One trial in 37 participants with idiopathic inflammatory myopathies also showed a significant improvement in functional performance. No trial reported any clinically relevant adverse event.In metabolic myopathies, meta-analyses of three cross-over trials including 33 participants revealed no significant difference in muscle strength. One trial reported a significant deterioration of activities of daily living (mean difference 0.54 on a 1 to 10 scale; 95% CI 0.14 to 0.93) and an increase in muscle pain during high-dose creatine treatment in McArdle disease.

AUTHORS' CONCLUSIONS

High quality evidence from RCTs shows that short- and medium-term creatine treatment increases muscle strength in muscular dystrophies. There is also evidence that creatine improves functional performance in muscular dystrophy and idiopathic inflammatory myopathy. Creatine is well tolerated in these people. High quality but limited evidence from RCTs does not show significant improvement in muscle strength in metabolic myopathies. High-dose creatine treatment impaired activities of daily living and increased muscle pain in McArdle disease.

Psychiatric symptoms correlate with metabolic indices in the hippocampus and cingulate in patients with mitochondrial disorders

There is increasing recognition that mitochondrial dysfunction may have a critical role in the pathophysiology of major psychiatric illnesses. Patients with mitochondrial disorders offer a unique window through which we can begin to understand the association between psychiatric symptoms and mitochondrial dysfunction in vivo. Using proton magnetic resonance spectroscopy ((1)H-MRS), we investigated metabolic indices in mitochondrial patients in regions of the brain that have been implicated in psychiatric illness: the caudate, cingulate cortex and hippocampus. In all, 15 patients with mitochondrial disorders and 15 age- and sex-matched controls underwent a comprehensive psychiatric assessment, including the administration of standardized psychiatric rating scales, followed by single voxel (1)H-MRS of the caudate, cingulate cortex and hippocampus to measure N-acetyl aspartate (NAA), creatine (Cr), glycerophosphocholine (GPC), myoinositol and glutamate+glutamine (Glx). Pearson's correlation coefficients were used to determine correlations between metabolites and the psychiatric rating scales. Anxiety symptoms in these patients correlated with higher GPC, Glx, myoinositol and Cr in the hippocampus. Impaired level of function as a result of psychiatric symptoms correlated with higher Glx and GPC in the cingulate cortex. In summary, we found remarkably consistent, and statistically significant, correlations between anxiety and metabolic indices in the hippocampus in patients with mitochondrial disorders, while overall impairment of functioning due to psychiatric symptoms correlated with metabolic markers in the cingulate cortex. These findings lend support to the notion that mitochondrial dysfunction in specific brain regions can give rise to psychiatric symptoms. In particular, they suggest that metabolic processes in the hippocampus may have an important role in the neurobiology of anxiety.

A randomized, double-blind placebo-controlled trial of oral creatine monohydrate augmentation for enhanced response to a selective serotonin reuptake inhibitor in women with major depressive disorder

OBJECTIVE

Antidepressants targeting monoaminergic neurotransmitter systems, despite their immediate effects at the synaptic level, usually require several weeks of administration to achieve clinical efficacy. The authors propose a strategy of adding creatine monohydrate (creatine) to a selective serotonin reuptake inhibitor (SSRI) in the treatment of patients with major depressive disorder. Such augmentation may lead to a more rapid onset of antidepressant effects and a greater treatment response, potentially by restoring brain bioenergetics at the cellular level.

METHOD

Fifty-two women with major depressive disorder were enrolled in an 8-week double-blind placebo-controlled clinical trial and randomly assigned to receive escitalopram in addition to either creatine (5 g/day, N=25) or placebo (N=27). Efficacy was primarily assessed by changes in the Hamilton Depression Rating Scale (HAM-D) score.

RESULTS

In comparison to the placebo augmentation group, patients receiving creatine augmentation showed significantly greater improvements in HAM-D score, as early as week 2 of treatment. This differential improvement favoring creatine was maintained at weeks 4 and 8. There were no differences between treatment groups in the proportion of patients who discontinued treatment prematurely (creatine: N=8, 32.0%; placebo: N=5, 18.5%) or in the overall frequency of all reported adverse events (creatine: 36 events; placebo: 45 events).

CONCLUSIONS

The current study suggests that creatine augmentation of SSRI treatment may be a promising therapeutic approach that exhibits more rapid and efficacious responses in women with major depressive disorder.

Creatine supplementation with specific view to exercise/sports performance: an update

Creatine is one of the most popular and widely researched natural supplements. The majority of studies have focused on the effects of creatine monohydrate on performance and health; however, many other forms of creatine exist and are commercially available in the sports nutrition/supplement market. Regardless of the form, supplementation with creatine has regularly shown to increase strength, fat free mass, and muscle morphology with concurrent heavy resistance training more than resistance training alone. Creatine may be of benefit in other modes of exercise such as high-intensity sprints or endurance training. However, it appears that the effects of creatine diminish as the length of time spent exercising increases. Even though not all individuals respond similarly to creatine supplementation, it is generally accepted that its supplementation increases creatine storage and promotes a faster regeneration of adenosine triphosphate between high intensity exercises. These improved outcomes will increase performance and promote greater training adaptations. More recent research suggests that creatine supplementation in amounts of 0.1 g/kg of body weight combined with resistance training improves training adaptations at a cellular and sub-cellular level. Finally, although presently ingesting creatine as an oral supplement is considered safe and ethical, the perception of safety cannot be guaranteed, especially when administered for long period of time to different populations (athletes, sedentary, patient, active, young or elderly).

Suplementação com creatina associada ao treinamento resistido não altera as funções renal e hepática

A creatina é o suplemento nutricional mais popular utilizado para melhorar o desempenho em atividades que envolvem exercícios de curta duração e alta intensidade. Porém, as possíveis intercorrências advindas do seu uso não estão totalmente elucidadas. O objetivo do estudo foi avaliar os efeitos de duas dosagens de suplementação com creatina nas funções renal e hepática de adultos saudáveis durante oito semanas de treinamento de musculação. Exames bioquímicos foram realizados em 35 praticantes de musculação distribuídos aleatoriamente em três grupos, placebo (PLA, n = 12), creatina (CRE1, n = 12) e creatina 2 (CRE2, n = 11), antes e após oito semanas de treinamento com exercícios resistidos. Em desenho duplo-cego, os voluntários foram suplementados (20g/dia) com creatina (CRE1 e CRE2) ou placebo (PLA) por sete dias e nos 53 dias subsequentes com 0,03g/kg de massa corporal de creatina (CRE1) e placebo (PLA) e com 5g/dia o grupo CRE2. Não houve intervenção na composição de suas dietas, que foram registradas e analisadas. Os resultados dos exames bioquímicos realizados permaneceram dentro das faixas de normalidade. Os valores de creatinina aumentaram 12,2% no grupo CRE1 e 9,0%, no CRE2, enquanto que no grupo PLA diminuiu 4,7%, entretanto, esses valores não ultrapassaram os índices de normalidade. Os valores dos exames da função hepática diminuíram em quase todas as frações, em todos os tratamentos, contudo, sem significância estatística. Conclui-se que a suplementação com creatina nas dosagens utilizadas (0,03g/kg e 5g/dia) para indivíduos saudáveis por oito semanas não altera a função hepática ou renal, sendo assim, nas condições deste estudo, foi considerada segura.

Effect of creatine supplementation on measured glomerular filtration rate in postmenopausal women

We aimed to investigate whether creatine supplementation affects the measured glomerular filtration rate in postmenopausal women (age, 58 ± 3 years). Subjects were randomly assigned to receive either creatine (20 g·day–1 for 1 week and 5 g·day–1 thereafter) or a placebo. Kidney function was assessed at baseline and after 12 weeks. [51Cr]EDTA clearance remained unchanged (CR-PRE: 86.16 ± 14.36 mL·min–1 per 1.73 m2, POST: 87.25 ± 17.60 mL·min–1 per 1.73 m2; PL-PRE: 85.15 ± 8.54 mL·min–1 per 1.73 m2, POST: 87.18 ± 9.64 mL·min–1 per 1.73 m2; p = 0.81). Thus, we concluded that creatine supplementation does not affect glomerular filtration rate in postmenopausal women.

Neuroprotective effects of creatine

There is a substantial body of literature, which has demonstrated that creatine has neuroprotective effects both in vitro and in vivo. Creatine can protect against excitotoxicity as well as against β-amyloid toxicity in vitro. We carried out studies examining the efficacy of creatine as a neuroprotective agent in vivo. We demonstrated that creatine can protect against excitotoxic lesions produced by N-methyl-D: -aspartate. We also showed that creatine is neuroprotective against lesions produced by the toxins malonate and 3-nitropropionic acid (3-NP) which are reversible and irreversible inhibitors of succinate dehydrogenase, respectively. Creatine produced dose-dependent neuroprotective effects against MPTP toxicity reducing the loss of dopamine within the striatum and the loss of dopaminergic neurons in the substantia nigra. We carried out a number of studies of the neuroprotective effects of creatine in transgenic mouse models of neurodegenerative diseases. We demonstrated that creatine produced an extension of survival, improved motor performance, and a reduction in loss of motor neurons in a transgenic mouse model of amyotrophic lateral sclerosis (ALS). Creatine produced an extension of survival, as well as improved motor function, and a reduction in striatal atrophy in the R6/2 and the N-171-82Q transgenic mouse models of Huntington's disease (HD), even when its administration was delayed until the onset of disease symptoms. We recently examined the neuroprotective effects of a combination of coenzyme Q10 (CoQ10) with creatine against both MPTP and 3-NP toxicity. We found that the combination of CoQ and creatine together produced additive neuroprotective effects in a chronic MPTP model, and it blocked the development of alpha-synuclein aggregates. In the 3-NP model of HD, CoQ and creatine produced additive neuroprotective effects against the size of the striatal lesions. In the R6/2 transgenic mouse model of HD, the combination of CoQ and creatine produced additive effects on improving survival. Creatine may stabilize mitochondrial creatine kinase, and prevent activation of the mitochondrial permeability transition. Creatine, however, was still neuroprotective in mice, which were deficient in mitochondrial creatine kinase. Administration of creatine increases the brain levels of creatine and phosphocreatine. Due to its neuroprotective effects, creatine is now in clinical trials for the treatment of Parkinson's disease (PD) and HD. A phase 2 futility trial in PD showed approximately a 50% improvement in Unified Parkinson's Disease Rating Scale at one year, and the compound was judged to be non futile. Creatine is now in a phase III clinical trial being carried out by the NET PD consortium. Creatine reduced plasma levels of 8-hydroxy-2-deoxyguanosine in HD patients phase II trial and was well-tolerated. Creatine is now being studied in a phase III clinical trial in HD, the CREST trial. Creatine, therefore, shows great promise in the treatment of a variety of neurodegenerative diseases.

Creatine for treating muscle disorders

BACKGROUND

Progressive muscle weakness is a main symptom of most hereditary and acquired muscle diseases. Creatine improves muscle performance in healthy individuals. This is an update of our 2007 Cochrane review that evaluated creatine treatment in muscle disorders.

OBJECTIVES

To evaluate the efficacy of creatine compared to placebo for the treatment of muscle weakness in muscle diseases.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Specialized Register (4 October 2010), the Cochrane Central Register of Controlled Trials (11 October 2010, Issue 4, 2010 in The Cochrane Library), MEDLINE (January 1966 to September 2010) and EMBASE (January 1980 to September 2010) for randomised controlled trials (RCT) of creatine used to treat muscle diseases.

SELECTION CRITERIA

RCTs or quasi-RCTs of creatine treatment compared to placebo in hereditary muscle diseases or idiopathic inflammatory myopathies.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the selection criteria, assessed trial quality and extracted data. We obtained missing data from investigators.

MAIN RESULTS

The updated searches identified two new studies. A total of 14 trials, including 364 randomised participants, met the selection criteria. Meta-analysis of six trials in muscular dystrophies including 192 participants revealed a significant increase in muscle strength in the creatine group compared to placebo, with a weighted mean difference of 8.47%; (95% confidence intervals (CI) 3.55 to 13.38). Pooled data of four trials including 115 participants showed that a significantly higher number of patients felt better during creatine treatment compared to placebo with a risk ratio of 4.51 (95% CI 2.33 to 8.74). One trial in 37 participants with idiopathic inflammatory myopathies also showed a significant improvement in functional performance. No trial reported any clinically relevant adverse event. In metabolic myopathies, meta-analyses of three cross-over trials including 33 participants revealed no significant difference in muscle strength. One trial reported a significant deterioration of ADL (mean difference 0.54 on a 1 to 10 scale; 95% CI 0.14 to 0.93) and an increase in muscle pain during high-dose creatine treatment in McArdle disease.

AUTHORS' CONCLUSIONS

High quality evidence from RCTs shows that short- and medium-term creatine treatment increases muscle strength in muscular dystrophies. There is also evidence that creatine improves functional performance in muscular dystrophy and idiopathic inflammatory myopathy. Creatine is well tolerated in these people. High quality but limited evidence from RCTs does not show significant improvement in muscle strength in metabolic myopathies. High-dose creatine treatment impaired ADL and increased muscle pain in McArdle disease.

How much is too much? A case report of nutritional supplement use of a high-performance athlete

Although dietary nutrient intake is often adequate, nutritional supplement use is common among elite athletes. However, high-dose supplements or the use of multiple supplements may exceed the recommended daily allowance (RDA) of particular nutrients or even result in a daily intake above tolerable upper limits (UL). The present case report presents nutritional intake data and supplement use of a highly trained male swimmer competing at international level. Habitual energy and micronutrient intake were analysed by 3 d dietary reports. Supplement use and dosage were assessed, and total amount of nutrient supply was calculated. Micronutrient intake was evaluated based on RDA and UL as presented by the European Scientific Committee on Food, and maximum permitted levels in supplements (MPL) are given. The athlete's diet provided adequate micronutrient content well above RDA except for vitamin D. Simultaneous use of ten different supplements was reported, resulting in excess intake above tolerable UL for folate, vitamin E and Zn. Additionally, daily supplement dosage was considerably above MPL for nine micronutrients consumed as artificial products. Risks and possible side effects of exceeding UL by the athlete are discussed. Athletes with high energy intake may be at risk of exceeding UL of particular nutrients if multiple supplements are added. Therefore, dietary counselling of athletes should include assessment of habitual diet and nutritional supplement intake. Educating athletes to balance their diets instead of taking supplements might be prudent to prevent health risks that may occur with long-term excess nutrient intake.

The effects of the recommended dose of creatine monohydrate on kidney function

We report a case of a heretofore healthy 18-year-old man who presented with a 2-day history of nausea, vomiting and stomach ache while taking creatine monohydrate for bodybuilding purposes. The patient had acute renal failure, and a renal biopsy was performed to determine the cause of increased creatinine and proteinuria. The biopsy showed acute tubular necrosis. In the literature, creatine monohydrate supplementation and acute tubular necrosis coexistence had not been reported previously. Twenty-five days after stopping the creatine supplements, the patient recovered fully. Even recommended doses of creatine monohydrate supplementation may cause kidney damage; therefore, anybody using this supplement should be warned about this possible side effect, and their renal functions should be monitored regularly.

Effects of 28 days of resistance exercise and consuming a commercially available pre-workout supplement, NO-Shotgun(R), on body composition, muscle strength and mass, markers of satellite cell activation, and clinical safety markers in males

Purpose

This study determined the effects of 28 days of heavy resistance exercise combined with the nutritional supplement, NO-Shotgun^®, on body composition, muscle strength and mass, markers of satellite cell activation, and clinical safety markers.

Methods

Eighteen non-resistance-trained males participated in a resistance training program (3 × 10-RM) 4 times/wk for 28 days while also ingesting 27 g/day of placebo (PL) or NO-Shotgun^® (NO) 30 min prior to exercise. Data were analyzed with separate 2 × 2 ANOVA and t-tests (p < 0.05).

Results

Total body mass was increased in both groups (p = 0.001), but without any significant increases in total body water (p = 0.77). No significant changes occurred with fat mass (p = 0.62); however fat-free mass did increase with training (p = 0.001), and NO was significantly greater than PL (p = 0.001). Bench press strength for NO was significantly greater than PL (p = 0.003). Myofibrillar protein increased with training (p = 0.001), with NO being significantly greater than PL (p = 0.019). Serum IGF-1 (p = 0.046) and HGF (p = 0.06) were significantly increased with training and for NO HGF was greater than PL (p = 0.002). Muscle phosphorylated c-met was increased with training for both groups (p = 0.019). Total DNA was increased in both groups (p = 0.006), while NO was significantly greater than PL (p = 0.038). For DNA/protein, PL was decreased and NO was not changed (p = 0.014). All of the myogenic regulatory factors were increased with training; however, NO was shown to be significantly greater than PL for Myo-D (p = 0.008) and MRF-4 (p = 0.022). No significant differences were located for any of the whole blood and serum clinical chemistry markers (p > 0.05).

Conclusion

When combined with heavy resistance training for 28 days, NO-Shotgun^® is not associated with any negative side effects, nor does it abnormally impact any of the clinical chemistry markers. Rather, NO-Shotgun^® effectively increases muscle strength and mass, myofibrillar protein content, and increases the content of markers indicative of satellite cell activation.