Creatine
Effect of different frequencies of creatine supplementation on muscle size and strength in young adults.
Candow DG, Chilibeck PD, Burke DG, Mueller KD, Lewis JD.
J Strength Cond Res. 2011 Jul;25(7):1831-8.
The purpose was to determine if creatine supplementation, consumed immediately before and immediately after exercise, with different dosing frequency (i.e., 2 or 3 d wk) could enhance the gains in muscle size and strength from resistance training (RT) in young adults. A group of 38 physically active, nonresistance trained university students (21-28 years) was randomly allocated to 1 of 4 groups: CR2 (0.15 g·kg creatine during 2 d wk of RT; 3 sets of 10 repetitions; n = 11, 6 men, 5 women), CR3 (0.10 g·kg creatine during 3 d wk of RT; 2 sets of 10 repetitions; n = 11, 6 men, 5 women;), PLA2 (placebo during 2 d wk of RT; n = 8, 5 men, 3 women), and PLA3 (placebo during 3 d wk of RT; n = 8, 4 men, 4 women) for 6 weeks. Before and after training, measurements were taken for muscle thickness of the elbow and knee flexor and extensor muscle groups (ultrasound), 1-repetition maximumleg press and chest press strength, and kidney function (urinary microalbumin). Repeated-measures analysis of variance showed that strength and muscle thickness increased in all groups with training (p < 0.05). The CR2 (0.6 ± 0.9 cm or 20%; p < 0.05) and CR3 groups (0.4 ± 0.6 cm or 16.4%; p < 0.05) experienced greater change in muscle thickness of the elbow flexors compared to the PLA2 (0.05 ± 0.5 cm or 2.3%) and PLA3 groups (0.13 ± 0.7 cm or 6.3%). Men supplementing with creatine experienced a greater increase in leg press strength (77.3 ± 51.2 kg or 62%) compared to women on creatine (21.3 ± 10 kg or 34%, p < 0.05). We conclude that creatine supplementation during RT has a small beneficial effect on regional muscle thickness in young adults but that giving the creatine over 3 d wk did not differ from giving the same dose over 2 d wk. PMID: 21512399
Analysis of the efficacy, safety, and regulatory status of novel forms of creatine.
Jäger R, Purpura M, Shao A, Inoue T, Kreider RB.
Amino Acids. 2011 May;40(5):1369-83. Epub 2011 Mar 22.
Creatine has become one of the most popular dietary supplements in the sports nutrition market. The form of creatine that has been most extensively studied and commonly used in dietary supplements is creatine monohydrate (CM). Studies have consistently indicated that CM supplementation increases muscle creatine and phosphocreatine concentrations by approximately 15-40%, enhances anaerobic exercise capacity, and increases training volume leading to greater gains in strength, power, and muscle mass. A number of potential therapeutic benefits have also been suggested in various clinical populations. Studies have indicated that CM is not degraded during normal digestion and that nearly 99% of orally ingested CM is either taken up by muscle or excreted in urine. Further, no medically significant side effects have been reported in literature. Nevertheless, supplement manufacturers have continually introduced newer forms of creatine into the marketplace. These newer forms have been purported to have better physical and chemical properties, bioavailability, efficacy, and/or safety profiles than CM. However, there is little to no evidence that any of the newer forms of creatine are more effective and/or safer than CM whether ingested alone and/or in combination with other nutrients. In addition, whereas the safety, efficacy, and regulatory status of CM is clearly defined in almost all global markets; the safety, efficacy, and regulatory status of other forms of creatine present in today’s marketplace as a dietary or food supplement is less clear. PMID: 21424716
Whey protein and creatine as nutritional supplements.
Sundell J, Hulmi J, Rossi J.
Duodecim. 2011;127(7):700-5.
Nutritional supplements are very popular especially among athletes although some studies show either controversial or even negative results. However, whey protein and creatine seem to have positive effects on muscle size, strength and athletic performance without major adverse effects and high costs. Most studies have shown that supplementation of whey protein can enhance muscle growth in response to resistance training. Some studies also suggest that whey may enhance recovery from heavy exercise and possibly decrease muscle damage and soreness. Creatine supplementation increases the intracellular pool of phosphocreatine in skeletal muscle. Phosphocreatine provides a reserve of energy to rapidly regenerate ATP, which is consumed as a result of muscle contraction. Creatine has been studied in hundreds of clinical trials and has shown benefits including increased muscle strength, power and size. PMID: 21553504
Use of creatine in the elderly and evidence for effects on cognitive function in young and old.
Rawson ES, Venezia AC.
Amino Acids. 2011 May;40(5):1349-62
The ingestion of the dietary supplement creatine (about 20 g/day for 5 days or about 2 g/day for 30 days) results in increased skeletal muscle creatine and phosphocreatine. Subsequently, the performance of high-intensity exercise tasks, which rely heavily on the creatine-phosphocreatine energy system, is enhanced. The well documented benefits of creatine supplementation in young adults, including increased lean body mass, increased strength, and enhanced fatigue resistance are particularly important to older adults. With aging and reduced physical activity, there are decreases in muscle creatine, muscle mass, bone density, and strength. However, there is evidence that creatine ingestion may reverse these changes, and subsequently improve activities of daily living. Several groups have demonstrated that in older adults, short-term high-dose creatine supplementation, independent of exercise training, increases body mass, enhances fatigue resistance, increases muscle strength, and improves the performance of activities of daily living. Similarly, in older adults, concurrent creatine supplementation and resistance training increase lean body mass, enhance fatigue resistance, increase muscle strength, and improve performance of activities of daily living to a greater extent than resistance training alone. Additionally, creatine supplementation plus resistance training results in a greater increase in bone mineral density than resistance training alone. Higher brain creatine is associated with improved neuropsychological performance, and recently, creatine supplementation has been shown to increase brain creatine and phosphocreatine. Subsequent studies have demonstrated that cognitive processing, that is either experimentally (following sleep deprivation) or naturally (due to aging) impaired, can be improved with creatine supplementation. Creatine is an inexpensive and safe dietary supplement that has both peripheral and central effects. The benefits afforded to older adults through creatine ingestion are substantial, can improve quality of life, and ultimately may reduce the disease burden associated with sarcopenia and cognitive dysfunction. PMID: 21394604
Creatine in mouse models of neurodegeneration and aging.
Klopstock T, Elstner M, Bender A.
Amino Acids. 2011 May;40(5):1297-303
The supplementation of creatine has shown a marked neuroprotective effect in mouse models of neurodegenerative diseases (Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis). This has been assigned to the known bioenergetic, anti-apoptotic, anti-excitotoxic and anti-oxidant properties of creatine. As aging and neurodegeneration share pathophysiological pathways, we investigated the effect of oral creatine supplementation on aging in 162 aged wild-type C57Bl/6J mice. The median healthy life span of creatine-fed mice was 9% higher than in their control littermates, and they performed significantly better in neurobehavioral tests. In brains of creatine-treated mice, there was a trend toward a reduction of reactive oxygen species and significantly lower accumulation of the “aging pigment” lipofuscin. Expression profiling showed an upregulation of genes implicated in neuronal growth, neuroprotection, and learning. These data showed that creatine improves health and longevity in mice. Creatine may, therefore, be a promising food supplement to promote healthy human aging. However, the strong neuroprotective effects in animal studies of creatine have not been reproduced in human clinical trials (that have been conducted in Parkinson’s disease, Huntington’s disease, and amyotrophic lateral sclerosis). The reasons for this translational gap are discussed. One obvious cause seems to be that all previous human studies may have been underpowered. Large phase III trials over long time periods are currently being conducted for Parkinson’s disease and Huntington’s disease, and will possibly solve this issue. PMID: 21390530
Effect of 28 days of creatine ingestion on muscle metabolism and performance of a simulated cycling road race
Robert C Hickner, David J Dyck, Josh Sklar, Holly Hatley and Priscilla
Journal of the International Society of Sports Nutrition: Volume 7, Number 1
The effects of creatine supplementation on muscle metabolism and exercise performance during a simulated endurance road race was investigated. Twelve adult male (27.3 ± 1.0 yr, 178.6 ± 1.4 cm, 78.0 ± 2.5 kg, 8.9 ± 1.1 %fat) endurance-trained (53.3 ± 2.0 ml* kg-1* min-1, cycling ~160 km/wk) cyclists completed a simulated road race on a cycle ergometer (Lode), consisting of a two-hour cycling bout at 60% of peak aerobic capacity (VO2peak) with three 10-second sprints performed at 110% VO2 peak every 15 minutes. Cyclists completed the 2-hr cycling bout before and after dietary creatine monohydrate or placebo supplementation (3 g/day for 28 days). Muscle biopsies were taken at rest and five minutes before the end of the two-hour ride. There was a 24.5 ± 10.0% increase in resting muscle total creatine and 38.4 ± 23.9% increase in muscle creatine phosphate in the creatine group (P < 0.05). Plasma glucose, blood lactate, and respiratory exchange ratio during the 2-hour ride, as well as VO2 peak, were not affected by creatine supplementation. Submaximal oxygen consumption near the end of the two-hour ride was decreased by approximately 10% by creatine supplementation (P < 0.05). Changes in plasma volume from pre- to post-supplementation were significantly greater in the creatine group (+14.0 ± 6.3%) than the placebo group (-10.4 ± 4.4%; P < 0.05) at 90 minutes of exercise. The time of the final sprint to exhaustion at the end of the 2-hour cycling bout was not affected by creatine supplementation (creatine pre, 64.4 ± 13.5s; creatine post, 88.8 ± 24.6s; placebo pre, 69.0 ± 24.8s; placebo post 92.8 ± 31.2s: creatine vs. placebo not significant). Power output for the final sprint was increased by ~33% in both groups (creatine vs. placebo not significant). It can be concluded that although creatine supplementation may increase resting muscle total creatine, muscle creatine phosphate, and plasma volume, and may lead to a reduction in oxygen consumption during submaximal exercise, creatine supplementation does not improve sprint performance at the end of endurance cycling exercise. PMID: 20609257
Effect of creatine supplementation during resistance training on muscle accretion in the elderly.
Candow DG, Chilibeck PD.
J Nutr Health Aging. 2007 Mar-Apr;11(2):185-8.
Sarcopenia, defined as the age-related loss of muscle mass, is a serious health concern. Contributing factors to sarcopenia include physical inactivity and undernutrition. Resistance training has a positive effect on muscle mass in the elderly. However, muscle loss is still observed in older adults who perform weight bearing exercise; suggesting that nutrition is important. Creatine supplementation has the potential to increase muscle accretion during resistance training, although the mechanism for its ergogenic effect is unclear. Creatine has the potential to increase cellular hydration and myogenic transcription factors and facilitate the up-regulation of muscle specific-genes such as myosin heavy chain possibly leading to muscle hypertrophy. PMID: 17435961
Creatine for treating muscle disorders.
Kley RA, Tarnopolsky MA, Vorgerd M.
Cochrane Database Syst Rev. 2011 Feb 16;(2).
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. To evaluate the efficacy of creatine compared to placebo for the treatment of muscle weakness in muscle diseases. 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. RCTs or quasi-RCTs of creatine treatment compared to placebo in hereditary muscle diseases or idiopathic inflammatory myopathies. Two authors independently applied the selection criteria, assessed trial quality and extracted data. We obtained missing data from investigators. 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. 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. PMID: 21328269
Beneficial Effect of Creatine Supplementation in Knee Osteoarthritis.
Neves M Jr, Gualano B, Roschel H, Fuller R, Benatti FB, de Sá Pinto AL, Lima FR,
Pereira RM, Lancha AH Jr, Bonfá E.
Med Sci Sports Exerc. 2011 Feb 8
The aim of this study was to investigate the efficacy of creatine (CR) supplementation combined with strengthening exercises inknee osteoarthritis (OA). A randomized, double-blind, placebo-controlled trial was performed.Postmenopausal women with knee OA were allocated to receive either CR (20 g/dfor one week and 5 g/dthereafter) or placebo (PL) and were enrolled in a lower limb resistance training program. They were assessed at baseline (PRE) and after 12 weeks (POST). The primary outcome was the physical function as measured by the timed-stands test. Secondary outcomes included lean mass, quality of life, pain, stiffness, and muscle strength. Physical function was significantly improved only in the CR group (p=0.006). Additionally, a significant between-group difference was observed (CR-PRE: 15.7 ± 1.4, POST: 18.1 ± 1.8; PL-PRE: 15.0 ± 1.8, POST: 15.2 ± 1.2; p=0.004). The CR group also presented improvements in physical function and stiffness subscales as evaluated by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (p=0.005 and p=0.024, respectively), whereas the PL group did not show any significant changes in these parameters (p>0.05). Additionally, only the CR group presented a significant improvement in lower limb lean mass (p=0.04) as well as in quality of life (p=0.01). Both CR and PL groups demonstrated significant reductions in pain (p<0.05). Similarly, a main effect for time revealed an increase in leg-press 1-RM (p=0.005) with no significant differences between groups (p=0.81). CR supplementation improves physical function, lower limb lean mass and quality of life in postmenopausal women with knee OA undergoing strengthening exercises. PMID: 21311365