Wysłano 24 lutego 2011 16:40zgłoś naruszenie
również jak najlepiej stosowac kreatynę (faza ładowania vs. stałe dawki).
W tym temacie zaprezentuje kilka badań mówiących o efektach ubocznych (tj.braku efektów ubocznych !) po dlugotrwalym stosowaniu:
Long-term creatine supplementation does not significantly affect clinical markers of health in athletes.
Creatine has been reported to be an effective ergogenic aid for athletes. However, concerns have been raised regarding the long-term safety of creatine supplementation. This study examined the effects of long-term creatine supplementation on a 69-item panel of serum, whole blood, and urinary markers of clinical health status in athletes. Over a 21-month period, 98 Division IA college football players were administered in an open label manner creatine or non-creatine containing supplements following training sessions. Subjects who ingested creatine were administered 15.75 g/day of creatine monohydrate for 5 days and an average of 5 g/day thereafter in 5-10 g/day doses. Fasting blood and 24-h urine samples were collected at 0, 1, 1.5, 4, 6, 10, 12, 17, and 21 months of training. A comprehensive quantitative clinical chemistry panel was determined on serum and whole blood samples (metabolic markers, muscle and liver enzymes, electrolytes, lipid profiles, hematological markers, and lymphocytes). In addition, urine samples were quantitatively and qualitative analyzed to assess clinical status and renal function. At the end of the study, subjects were categorized into groups that did not take creatine (n = 44) and subjects who took creatine for 0-6 months (mean 4.4 +/- 1.8 months, n = 12), 7-12 months (mean 9.3 +/- 2.0 months, n = 25), and 12-21 months (mean 19.3 +/- 2.4 months, n = 17). Baseline and the subjects' final blood and urine samples were analyzed by MANOVA and 2 x 2 repeated measures ANOVA univariate tests. MANOVA revealed no significant differences (p = 0.51) among groups in the 54-item panel of quantitative blood and urine markers assessed. Univariate analysis revealed no clinically significant interactions among groups in markers of clinical status. In addition, no apparent differences were observed among groups in the 15-item panel of qualitative urine markers. Results indicate that long-term creatine supplementation (up to 21-months) does not appear to adversely effect markers of health status in athletes undergoing intense training in comparison to athletes who do not take creatine
98 rugbistów przyjmowalo kreatyne przez 21 miesiecy (!) w dawce 5-10g
po tym okresie zmierzono 54 parametry z krwi i 15 z moczu
zadnych istotnych roznic nie wykazano miedzy grupa 98 rygbistow a grupa placebo
Creatine supplementation and health variables: a retrospective study.
PURPOSE: Long-term safety of creatine supplementation has been questioned. This retrospective study was performed to examine markers related to health, the incidence of reported side effects and the perceived training benefits in athletes supplementing with creatine monohydrate.
METHODS: Twenty-six athletes (18 M and 8 F, 24.7 +/- 9.2 y; 82.4 +/- 20.0 kg; 176.5 +/- 8.8 cm) from various sports were used as subjects. Blood was collected between 7:00 and 8:30 a.m. after a 12-h fast. Standard clinical examination was performed for CBC and 27 blood chemistries. Testosterone, cortisol, and growth hormone were analyzed using an ELISA. Subjects answered a questionnaire on dietary habits, creatine supplementation, medical history, training history, and perceived effects of supplementation. Body mass was measured using a medical scale, body composition was estimated using skinfolds, and resting heart rate and blood pressure were recorded. Subjects were grouped by supplementation length or no use: Gp1 (control) = no use (N = 7; 3 F, 4 M); Gp2 = 0.8-1.0 yr (N = 9; 2 F, 7 M); and Gp3 = 1(+) (N = 10; 3 F, 7 M).
RESULTS: Creatine supplementation ranged from 0.8--4 yr. Mean loading dose for Gp2 and Gp3 was 13.7 +/- 10.0 and the maintenance dose was 9.7 +/- 5.7 g.d(-)1. Group differences were analyzed using one-way ANOVA.
CONCLUSIONS: Expected gender differences were observed. Of the comparisons made among supplementation groups, only two differences for creatinine and total protein (P < 0.05) were noted. All group means fell within normal clinical ranges. There were no differences in the reported incidence of muscle injury, cramps, or other side effects. These data suggest that long-term creatine supplementation does not result in adverse health effects.
26 atletów (kobiety=8 & mezczyzni=18) przyjmowalo kreatyne w ilosci 5-10g przez okres od 8miesięcy do 4 lat
jedyne róznice jakie zauważono to róznice oddzialywania kreatyny na różną płeć
jesli chodzi o okolo 30wskaznikow krwi - nie wykazano istotnych roznic pomiedzy nimi a grupa placebo
Long-term oral creatine supplementation does not impair renal function in healthy athletes.
PURPOSE: Oral creatine supplementation is widely used in sportsmen and women. Side effects have been postulated, but no thorough investigations have been conducted to support these assertions. It is important to know whether long-term oral creatine supplementation has any detrimental effects on kidney function in healthy population.
METHODS: Creatinine, urea, and plasma albumin clearances have been determined in oral creatine consumers (10 months to 5 yr) and in a control group.
RESULTS: There were no statistical differences between the control group and the creatine consumer group for plasma contents and urine excretion rates for creatinine, urea, and albumin. Clearance of these compounds did not differ between the two groups. Thus, glomerular filtration rate, tubular reabsorption, and glomerular membrane permeability were normal in both groups.
CONCLUSIONS: Neither short-term, medium-term, nor long-term oral creatine supplements induce detrimental effects on the kidney of healthy individuals.
przyjmowanie kreatyny w okresie od 10 miesiecy do 5lat - w porownaniu do grupy placebo ,nie wykazuje istotnych róznic
+ kilka badań ze starego teamtu:
Creatine: a review of efficacy and safety.
Although oral creatine supplementation is very popular among athletes, no prospective placebo-controlled studies on the adverse effects of long-term supplementation have yet been conducted. We performed a double-blind, placebo-controlled trial of creatine monohydrate in patients with the neurodegenerative disease amyotrophic lateral sclerosis, because of the neuroprotective effects it was shown to have in animal experiments. The purpose of this paper is to compare the adverse effects, and to describe the effects on indirect markers of renal function of long-term creatine supplementation. 175 subjects (age = 57.7 +/- 11.1 y) were randomly assigned to receive creatine monohydrate 10 g daily or placebo during an average period of 310 days. After one month, two months and from then on every fourth month, adverse effects were scored using dichotomous questionnaires, plasma urea concentrations were measured, and urinary creatine and albumin concentrations were determined. No significant differences in the occurrence at any time of adverse effects due to creatine supplementation were found (23 % nausea in the creatine group, vs. 24 % in the placebo group, 19 % gastro-intestinal discomfort in the creatine group, vs. 18 % in the placebo group, 35 % diarrhoea in the creatine group, vs. 24 % in the placebo group). After two months of treatment, oedematous limbs were seen more often in subjects using creatine, probably due to water retention. Severe diarrhoea (n = 2) and severe nausea (n = 1) caused 3 subjects in the creatine group to stop intake of creatine, after which these adverse effects subsided. Long-term supplementation of creatine did not lead to an increase of plasma urea levels (5.69 +/- 1.47 before treatment vs. 5.26 +/- 1.44 at the end of treatment) or to a higher prevalence of micro-albuminuria (5.4 % before treatment vs. 1.8 % at the end of treatment).
suplementacja kreatyna przez okres 310 dni nie miala zadnego lub tez wiekszego wplywu na zdrowie osob w porownaniu do grupy placebo
Creatine: a review of efficacy and safety.
Despite the many clinical trials, high-quality research is lacking. Laboratory investigations of endurance isotonic exercises, strength and endurance during isotonic exercises, isokinetic torque, isometric force, and ergometer performance have yielded roughly an equal number of published studies showing a positive effect or lack of effect. Field studies (i.e., on subjects participating in sports activities) are less impressive than laboratory studies. Performance was more often improved for short-duration, high-intensity activities. Reports have linked creatine to weight gain, cramping, dehydration, diarrhea, and dizziness. Creatine may decrease renal function, but only two case reports of this effect have been published. Creatine appears to be well tolerated in short-term trials.
wedlug niektorych zrodel kreatyna moze pogarszac prace nerek - ale tylko dwa badania wskazuja na takie dzialanie (znajac zycie badano wplyw kretyny na ludzi z uszkodzana fukncja nerek)
suma sumarum - kreatyna wydaje sie byc dobrze tolerowana substancja w w krotkich cyklach!
Is the use of oral creatine supplementation safe?
This review focuses on the potential side effects caused by oral creatine supplementation on gastrointestinal, cardiovascular, musculoskeletal, renal and liver functions. No strong evidence linking creatine supplementation to deterioration of these functions has been found. In fact, most reports on side effects, such as muscle cramping, gastrointestinal symptoms, changes in renal and hepatic laboratory values, remain anecdotal because the case studies do not represent well-controlled trials, so no causal relationship between creatine supplementation and these side-effects has yet been established. The only documented side effect is an increase in body mass. Furthermore, a possibly unexpected outcome related to creatine monohydrate ingestion is the amount of contaminants present that may be generated during the industrial production. Recently, controlled studies made to integrate the existing knowledge based on anecdotal reports on the side effects of creatine have indicated that, in healthy subjects, oral supplementation with creatine, even with long-term dosage, may be considered an effective and safe ergogenic aid. However, athletes should be educated as to proper dosing or to take creatine under medical supervision.
kreatyne posadza sie o powodowanie roznych skutkow ubocznych - jak od problemow z ukladem pokarmowym,uszkodzenia watroby czy inne - tak do tej pory nie znaleziono ewidentnych wnioskow aby kreatyna powodowala takie skutki!
Side effects of creatine supplementation in athletes.
CONTEXT: Allegations about side effects of creatine supplementation by athletes have been published in the popular media and scientific publications.
PURPOSE: To examine the experimental evidence relating to the physiological effects of creatine supplementation.
RESULTS: One of the purported effects of oral creatine supplementation is increased muscle mass. A review of the literature reveals a 1.0% to 2.3% increase in body mass, which is attributed to fat-free mass and, more specifically, to skeletal-muscle mass. Although it is unlikely that water retention can completely explain these changes, increase in muscle-protein synthesis has never been observed after creatine supplementation. Indirect evidence based on mRNA analyses suggests that transcription of certain genes is enhanced. Although the effect of creatine on muscle-protein synthesis seems irrefutable according to advertising, this allegation remains under debate in the scientific literature. The kidneys appear to maintain their functionality in healthy subjects who supplement with creatine, even over several months.
CONCLUSION: The authors, however, think that creatine supplementation should not be used by an individual with preexisting renal disease and that risk should be evaluated before and during any supplementation period. Even if there is a slight increase in mutagenic agents (methylamine and formaldehyde) in urine after a heavy load of creatine (20 g/day), their excretion remains within a normal range. No data are currently available regarding the potential production of heterocyclic amines with creatine supplementation. In summary, the major risk for health is probably associated with the purity of commercially available creatine.
wedlug badan kreatyna powoduje wzrost beztluszczowej masy ciala srednio o 1-2,3%
co nie stanowi tluszcz - tylko beztluszczowa masa miesniowa!
retencja wody nie moze wyjasnic czy byc odpowiedzialna za te zmiany - ale nigdy nie badano wplywu kreatyny na synteze bialka
jesli chodzi o nerki - krotkie cykle nie maja zadnego wplywu na jej dzialanie!
w czasie cykli kiedy spozywane sa olbrzymie ilosci kreatyny (20g/dzien)
fakt - wzrosta ilosc mutagenow - ale wszystko dalej miesci sie w granicach norm!
najwazniejsze - negatywny wplyw (jesli juz) kreatyny na nasze zdrowie w najwiekszym stopniu jest powiazany z czystoscia kreatyny jaka spozywamy!
Zmieniony przez - solaros w dniu 2011-02-24 16:42:19
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