Can glutamine slow muscle breakdown?
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Glutamine is a nonessential amino acid that is becoming a popular supplement for weight lifters and bodybuilders. It has been touted as a substance that results in a net gain of muscle protein and thus muscle mass. From the discussion of proteins, you will recall that body proteins are broken down and rebuilt on a daily basis. This is called protein turnover and it reflects the dynamic efforts of our cells to adapt to metabolic conditions that change minute by minute, hour by hour, and day by day. In muscle tissue, protein turnover reflects demands placed on muscle itself. In response to a weight lifting session there will be an increase in the breakdown of muscle proteins as well as production (synthesis) of muscle proteins. Together these seemingly counteractive processes drive muscle repair and adaptation and can endure for several hours to a day or more. When protein production exceeds breakdown, there will be a net growth of muscle tissue as seen in weight training. It is a matter of algebra. |
Glutamine is often purported to limit these breakdowns, which results in greater net gains of muscle protein. Interestingly, there are several review articles related to glutamine and muscle protein turnover and the potential application to athletes. However, the review articles outnumber the research efforts actually testing glutamine. Therefore, at this time, there is limited information with regard to the efficacy of glutamine supplementation to enhance muscle development associated with resistance training.
Can HMB (β-hydroxy β-methylbutyrate) improve muscle development?
HMB is the abbreviation for β-hydroxy β-methylbutyrate, which is a derivative of the essential amino acid leucine. HMB is a fairly popular supplement with weight trainers at this time and it also added to some sport bars. HMB may also be found in limited amounts in citrus and catfish. At this time there a several research articles that suggest that HMB supplementation (1.5 or 3 grams of HMB daily) for a couple weeks improved the strength and lean body mass of previously untrained men. However, not all research studies have shown this to be the case, especially in more highly trained individuals. At this time HMB is one of the sport nutrition ingredients that is worthy of experimentation.
Can beta-alanine improve performance?
Beta-alanine is naturally found in meats and is a little different structurally from alanine and the other amino acids that can be used to make proteins. However beta-alanine can be combined with histidine to make sarcosine. Sarcosine , which is an important acid buffer in muscle cells, especially Type II. However, ingested sarcosine is broken down in the blood and thus supplementation of carnosine does not effectively increase muscle carnosine levels. Meanwhile beta-alanine can enter muscle cells and be used to make carnosine. Researchers are finding that supplemental beta-alanine is indeed effective in raising muscle carnosine levels as well as improving the muscle acid buffering abilities during high intensity activities such as sprinting and weight training. This in turn is related to improvements in performance. One of the down-sides to beta-alanine supplementation is that it you will have to take a few grams daily. Furthermore, beta-alanine levels around or above 800 milligrams seems to result in a "flushing" and tingling sensation of the skin, which is often referred to as parastesia. Thus, supplementation should be split up over the day.
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