Creatine is a nitrogenous amine. Normal daily dietary intake of creatine from an omnivorous diet approximates one gram. Dietary sources of creatine include meat, fish and other animal products, but it may also be formed endogenously in the liver, kidney and pancreas from the amino acids glycine, arginine and methionine. One-half kilogram of fresh, uncooked steak contains about two grams of creatine. Creatine has become an extremely popular dietary supplement among strength-power athletes. In 1998, about $200 million was spent on creatine monohydrate. Of the approximately 350 studies evaluating the potential ergogenic (performance-enhancing) value of creatine supplementation, most of them report statistically significant results. It should be noted, however, that studies reporting no statistically significant benefit of creatine supplementation often have low statistical power, have evaluated performance tests with large test-to-test variability, and/or haven't incorporated appropriate experimental controls. Thus, the predominance of research indicates that creatine supplementation represents an effective nutritional method to enhance athletic performance, especially muscle size and strength responses to resistance training (Nutrition, 2004 Jul-Aug;20(7-8):609-14). Specifically, short-term creatine supplementation has been reported to improve:
- Maximum power/strength
- Work performed during sets of maximum-effort muscle contractions
- Single-effort sprint performance
- Work performed during repetitive sprint performance
- Body composition, i.e., creatine supplementation during training promotes greater gains in fat-free mass.
Post-Exercise Recovery Drink
It's very important to take in fast-acting proteins and carbohydrates immediately after resistance exercise. In my view, a post-exercise recovery drink should contain hydrolyzed (pre-digested) whey protein, some high-glycemic carbohydrates and certain added amino acids (e.g., leucine). A good example of such a product is ProSource's After Mass. This comprehensive formula contains quick absorbing whey and casein hydrolysates in the exact ratios founds in mother's milk. In addition, After Mass contains high-glycemic carbs and is enriched with branched chain amino acids (leucine, isoleucine, and valine), glutamine, glycine and taurine.
Why is high-quality protein hydrolysate ideal for post-exercise recovery? Well, the hydrolysis process mimics our own digestive actions, thus making it an ideal way to process dietary protein. Studies indicate that protein hydrolysates containing mostly di- and tri-peptides are absorbed more rapidly than free form amino acids and much more rapidly than intact (non-hydrolyzed) proteins (Journal of Sports Science and Medicine, 2004 June;3:60-63). Obviously, this is a desirable trait for serious athletes who wish to maximize amino acid delivery to the muscle immediately after exercise. The purpose of the recent study at the Copenhagen Muscle Research Center was to determine the effects different protein-containing meals (protein hydrolysates versus intact proteins) have on the magnitude and direction of insulin and glucagon responses (Journal of Nutrition, 2002 Aug;132(8):2174-82). A further aim was to determine the rate of appearance of amino acids. This study indicated that:
- Ingestion of glucose and protein hydrolysate results in a synergistic and fast increase in blood insulin.
- Protein hydrolysates are absorbed at a faster rate from the small intestine than are intact milk proteins.
- Whey protein hydrolysate elicited the greatest availability of amino acids during the three-hour postprandial (occurring after a meal) period.
Branched-Chain Amino Acids (Especially Leucine)
The role of amino acids as substrates for protein synthesis (i.e., building blocks of protein) is well established. However, a function for amino acids in modulating the signal pathways regulating muscle protein anabolism has only recently been described. The stimulation of protein synthesis in skeletal muscle produced by an intake of a mixed meal is due largely to branched-chain amino acids (leucine, isoleucine, valine; BCAAs). Of the three BCAAs, leucine is clearly the most effective. In fact, a recent study at Baylor College of Medicine suggests that the postprandial (occurring after meal) rise in leucine, but not isoleucine or valine, acts as a nutrient signal to stimulate muscle protein anabolism. To my knowledge, there's only one study examining direct ergogenic effects of leucine supplementation. Dr. Crowe and co-workers investigated the effects of leucine supplementation on the exercise performance of outrigger canoeists (European Journal of Applied Physiology, 2005 Oct 29;1-9). Thirteen canoeists underwent testing before and after six weeks of supplementation with either leucine (45 milligrams per kilogram per day) or placebo (fake supplement). The results revealed that leucine supplementation significantly improved endurance performance and upper body power in outrigger canoeists. The authors speculated that the ergogenic effects of leucine were likely related to a reduction in skeletal muscle damage with training and/or an increase in skeletal muscle protein anabolism. Indeed, there's evidence that BCAA supplementation before exercise decreases the breakdown of muscle proteins during exercise in humans and that leucine strongly promotes protein anabolism in skeletal muscle. Furthermore, it's been reported that BCAA supplementation prior to resistance training decreased delayed-onset muscle soreness and muscle fatigue occurring for a few days after exercise, suggesting BCAA supplementation may be useful for muscle recovery following exercise. Also, there's some evidence suggesting that BCAA supplementation may delay central fatigue during prolonged exercise. Finally, it was recently proposed that leucine is a key to the metabolic advantage of a higher-protein diet because of its unique role in the regulation of muscle protein anabolism, insulin signalling and glucose recycling via alanine. Leucine appears to regulate the burning of glucose by skeletal muscle through stimulation of glucose recycling via the glucose-alanine cycle. These mechanisms produce muscle mass sparing and provide a stable blood sugar environment during energy-restricted diets. Although leucine plays an important role in preservation of muscle protein (Nutrition & Metabolism, 2006 Jan 31;3:9), it's not the only factor behind the metabolic advantage of low-carb/high protein diets (Journal of the International Society of Sports Nutrition, 2004;1(2):21-26, 2004). Carbohydrate restriction dramatically lowers insulin levels and insulin signalling in fat tissue plays a very important role in fat storage. Concerning safety, toxicity studies have shown that BCAAs are safe amino acids when the three BCAAs are provided in a ratio similar to that of animal protein (i.e., a 2:1:1 leucine:isoleucine:valine ratio). One serving of ProSource's Mega BCAA contains 1200 mg of leucine, 600 mg of isoleucine, and 600 mg of valine 600mg. ProSource recommends that one take 4 capsules two times per day. I feel higher amounts are also beneficial for optimal results (e.g., 8 capsules before and after exercise). ProSource's Myo-Surge also contains BCAAs as well as glutamine, tyrosine, vitamin C and a host of other ingredients. ProSource utilizes only premium -grade BCAAs from the world's leading supplier in Japan.
Protein and Meal-Replacement Powders
Historically, bodybuilders and other strength-power athletes have always consumed a lot of protein supplements. Protein supplements are used simply because they work. However, it's important to emphasize the point that these supplements should be used as an adjunct to an otherwise balanced nutritional plan, not as a substitute for one. Whey protein, particularly CFM whey isolate protein, has been singled out as the ultimate source of protein based on an excellent amino acid profile and rapidity of digestion. Drs. Ewan Hu and Michael Zemel published an excellent scientific review on whey protein in the respected Journal of Nutritional Biochemistry (2003 May;14(5):251-8). They concluded that whey protein supplementation may enhance lean body mass in conjunction with appropriate training. The authors also pointed out that bioactive compounds isolated from whey may also improve immune function and gastrointestinal health. Thus, it appears whey protein (e.g., ProSource's NytroWhey which is 100% pure CFM whey isolate protein) is the ultimate source of protein for serious athletes. There are also a number of studies investigating long-term weight maintenance using meal replacement products (relatively high in protein), either self-managed, with active dietary counselling, or with behavioural programs compared with traditional caloric-restricted diet plans. All the studies resulted in maintenance of significant weight loss after two to five years of follow-up. Interestingly, meal replacements were also found to improve food patterns, including nutrient distribution, intake of macronutrients, and maintenance of fruit and vegetable intake.
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About the Author Anssi Manninen, M.H.S., is a well-published research scientist in the sports nutrition field. He holds an M.H.S. in sports medicine from the University of Kuopio Medical School. His current position is Senior Science Editor at Advanced Research Press, a publisher of Muscular Development, FitnessRx for Men, and FitnessRx for Women. Anssi is also an Associate Editor for Nutrition & Metabolism www.nutritionandmetabolism.com, a leading scientific journal in the area of nutritional biochemistry.
This article expresses the author's views and does not necessarily reflect those of Advanced Research Press. The information provided herein is for informational and educational purposes only and is not intended to substitute for the advice of your physician or other health care professional.