| An adequate supply of macro nutrients and | | | | A couple factors must be taken into account |
| micronutrients are required for survival, growth, and | | | | regarding the degradation of cellular protein? The |
| development, and for the maintenance of health and | | | | half-lives of different proteins vary tremendously |
| well-being throughout life. Regarding skeletal muscle | | | | between and within cells. Also, proteins do not exist |
| growth, the accretion of protein (primarily contractile) | | | | within solution intracellularly but are part of distinct |
| represents one of the primary goals that a select | | | | structures (e.g., contractile protein, cytoskeleton, etc.) |
| group of athletes (e.g., bodybuilders, powerlifters, | | | | within the cell. If the integrity of each cell is to be |
| Olympic-style weightlifters) aspire towards. Rates of | | | | maintained, the degradation of various proteins within |
| protein accretion (and loss) are a function of the | | | | a cell must be regulated smoothly. Regarding skeletal |
| balance between protein synthesis and degradation. | | | | muscle, there is evidence that myofibrillar and |
| An increase in skeletal muscle mass can occur via an | | | | nonmyofibrillar protein are independently regulated. |
| increase in synthesis, a decrease in degradation, or a | | | | Thus, when examining the existing data on how |
| combination of the two. Note that each process is | | | | various dietary supplements affect protein synthesis |
| mechanistically distinct. That is, one can occur in the | | | | and degradation, one must remain cognizant of the |
| absence of changes in the other. | | | | fact that wholebody protein synthesis and |
| Nutritional status and the hormonal milieu present in | | | | degradation may (or may not) reflect changes in |
| the body have a profound impact on how protein is | | | | skeletal muscle protein synthesis and degradation. |
| used (i.e., oxidized, used to make additional contractile | | | | The supplements that this chapter will cover are |
| or noncontractile protein, etc.). Various supplements | | | | those that have been touted as anticatabolic. It |
| have been touted as muscle-builders" based on the | | | | would seem plausible that a decrease in protein |
| notion that they impact protein metabolism, | | | | degradation with no change in protein synthesis |
| specifically, via an inhibition of protein degradation. | | | | should result in the accumulation of extra protein. This |
| Some of these supplements, it is clear, do in fact | | | | of course would be particularly important for athletes |
| ameliorate the decline in protein synthesis seen under | | | | involved in the strength-power sports (i.e. |
| certain stressful states; however, protein synthesis | | | | bodybuilding, powerlifting, Olympic-style weightlifting, |
| may also be affected when these supplements are | | | | shot put, discus throw, etc. |
| consumed. | | | | |