Amino Acids Speed Muscle Recovery

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Amino Acids Speed Muscle Recovery
3/9/06 -

Healthnotes Newswire—Supplementing with a mixture of amino acids may lead to quicker muscle recovery after exercise and could reduce muscle damage caused by strenuous exercise, reports the Journal of Nutrition (2006;136:538S–43S).

Amino acids are the building blocks for proteins in the body. Twenty different amino acids are used for the growth, repair, and maintenance of tissues, and some of these are also used as an energy source for skeletal muscle. Nine amino acids are considered essential because the body cannot manufacture them, so they must be acquired through diet. While animal foods (meat, poultry, dairy products, and eggs) are the richest source of amino acids, substantial quantities are also found in plant-based foods.

The branched-chain amino acids (BCAAs—leucine, isoleucine, and valine) help maintain muscle tissue. During exercise, muscle stores of BCAAs may be used as an energy source. Arginine, another amino acid, promotes the release of hormones such as insulin and growth hormone, helps support immune function, and is involved in wound healing. Glutamine, the most abundant amino acid in the body, provides glucose for energy and enhances immune function. Glutamine is especially helpful for preventing immune system suppression that may occur after bouts of intense physical exercise.

The new study reviewed trials that used an amino acid combination over long periods of time to determine its effects on muscle strength and recovery after exercise, and its ability to prevent muscle damage caused by intense exercise. All of the studies used an amino acid mixture containing 14% glutamine, 14% arginine, 30% BCAAs, and seven other amino acids.

In the first study, male students (ages 19 to 21) took 5.6 grams of the mixture two times per day or placebo during a ten-day recovery period following an exercise training session. After two months, the treatment groups were switched. The group taking the amino acid mixture saw greater muscle strength and a faster rate of muscle recovery than the placebo group.

In another study, 48 men took part in an endurance exercise session followed by a four-day recovery period. The men received the amino acid mixture two times per day (unspecified amount) or a placebo before and after exercise and during the recovery period. After four weeks, the treatments were switched. Lowered blood levels of creatine phosphokinase—CPK, an indicator of muscle breakdown—suggested a protective effect of the amino acid mixture on muscle tissue.

During a six-month study, 13 athletes took three different amounts (2.2, 4.4, and 6.6 grams per day) of the amino acid mixture, each for one month. Blood samples were taken at the beginning and end of each trial to determine the mixture's effects on muscle damage and aerobic fitness. At a dose of 6.6 grams per day, CPK levels were significantly reduced at the end of the trial and measures of red blood cell function were improved, suggesting better aerobic fitness after supplementation with the amino acid combination. The athletes also rated their physical condition as significantly improved after taking the highest dose.

Lastly, a trial involving 23 rugby players studied the effects of taking 7.2 grams of the amino acid mixture for three months during intensive physical training. Blood samples were taken before and at the end of the study to assess the response to treatment. Compared with baseline values, hemoglobin and hematocrit levels and red blood cell counts were significantly higher at the end of the training period, suggesting an improvement in aerobic fitness.

Together, these results suggest that taking between 6 and 11 grams per day of an amino acid mixture may enhance aerobic fitness and favorably affect muscle function by reducing muscular injury and hastening recovery time after exercise.

—Kimberly Beauchamp, ND