nunca achei estudos cientificos provando que a glutamina é benéfico,
https://www.jissn.com/content/7/1/7
ISSN exercise & sport nutrition review: research & recommendations
Muscle Building Supplements
The following provides an analysis of the literature regarding purported weight gain supplements and our general interpretation of how they should be categorized based on this information. Table3 summarizes how we currently classify the ergogenic value of a number of purported performance-enhancing, muscle building, and fat loss supplements based on an analysis of the available scientific evidence.
Apparently Ineffective
Glutamine
Glutamine is the most plentiful non-essential amino acid in the body and plays a number of important physiological roles [31,108,109] Glutamine has been reported to increase cell volume and stimulate protein [151,152] and glycogen synthesis [153]. Despite its important role in physiological roles, there is no compelling evidence to support glutamine supplementation in terms of increasing lean body mass. One study that is often cited in support of glutamine supplementation and its role in increasing muscle mass was published by Colker and associates[154]. It was reported that subjects who supplemented their diet with glutamine (5 grams) and BCAA (3 grams) enriched whey protein during training promoted about a 2 pound greater gain in muscle mass and greater gains in strength than ingesting whey protein alone. While a 2 pound increase in lean body mass was observed, it is likely that these gains were due to the BCAAs that were added to the whey protein. In a well-designed investigation, Candow and co-workers [155] studied the effects of oral glutamine supplementation combined with resistance training in young adults. Thirty-one participants were randomly allocated to receive either glutamine (0.9 g/kg of lean tissue mass) or a maltodextrin placebo (0.9 g/kg of lean tissue mass) during 6 weeks of total body resistance training. At the end of the 6-week intervention, the authors concluded glutamine supplementation during resistance training had no significant effect on muscle performance, body composition or muscle protein degradation in young healthy adults. While there may be other beneficial uses for glutamine supplementation, there does not appear to be any scientific evidence that it supports increases in lean body mass or muscular performance.
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Creatine monohydrate
In our view, the most effective nutritional supplement available to athletes to increase high intensity exercise capacity and muscle mass during training is creatine monohydrate. Numerous studies have indicated that creatine supplementation increases body mass and/or muscle mass during training [70] Gains are typically 2 - 5 pounds greater than controls during 4 - 12 weeks of training [71]. The gains in muscle mass appear to be a result of an improved ability to perform high intensity exercise enabling an athlete to train harder and thereby promote greater training adaptations and muscle hypertrophy [72-75]. The only clinically significant side effect occasionally reported from creatine monohydrate supplementation has been the potential for weight gain[71,76-78] Although concerns have been raised about the safety and possible side effects of creatine supplementation [79,80], recent long-term safety studies have reported no apparent side effects [78,81,82] and/or that creatine monohydrate may lessen the incidence of injury during training [83-85]. Additionally a recent review was published which addresses some of the concerns and myths surrounding creatine monohydrate supplementation [86]. Consequently, supplementing the diet with creatine monohydrate and/or creatine containing formulations seems to be a safe and effective method to increase muscle mass.
The ISSN position stand on creatine monohydrate [87] summarizes their findings as this:
1. Creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes in terms of increasing high-intensity exercise capacity and lean body mass during training.
2. Creatine monohydrate supplementation is not only safe, but possibly beneficial in regard to preventing injury and/or management of select medical conditions when taken within recommended guidelines.
3. There is no compelling scientific evidence that the short- or long-term use of creatine monohydrate has any detrimental effects on otherwise healthy individuals.
4. If proper precautions and supervision are provided, supplementation in young athletes is acceptable and may provide a nutritional alternative to potentially dangerous anabolic drugs.
5. At present, creatine monohydrate is the most extensively studied and clinically effective form of creatine for use in nutritional supplements in terms of muscle uptake and ability to increase high-intensity exercise capacity.