Sports Supplement Update

Recovery Drinks, HMB and Myostatin Blockers

Performance enhancement is not against the spirit of sport; it is the spirit of sport. To choose to be better is to be human. Athletes should be the given this choice. -Dr. Savulescu and colleagues

                         British Journal of Sports Medicine, 2004;38:666-670

            Post-Exercise Recovery: Beyond Carb Drinks

            The purpose of the recent study by Dr. Rene Koopman and colleagues at Maastricth University was to examine post-exercise muscle protein synthesis (anabolism) following the combined ingestion of carbs with or without protein and/or free leucine. Eight male subjects were randomly assigned to three trials during which they consumed drinks containing either 1) carbs only; 2) carbs + protein; or 3) carbs + protein + leucine.

            Not surprisingly, the insulin response during the entire six-hour post-exercise period was substantially greater in the carbs + protein + leucine trial compared to the carbs only and carbs + protein trials. Also, muscle protein synthesis rates were higher when protein and leucine were co-ingested. According to the authors of this study, "The present data indicate that the additional ingestion of free leucine in combination with protein and carbohydrate likely represents an effective strategy to increase muscle anabolism following resistance exercise."

            Post-Exercise Recovery: Whey vs. Casein

            Dr. Kevin Tipton and co-workers at the University of Texas Medical Branch examined the acute response of muscle anabolism to ingestion of two different protein supplements (casein vs. whey) after resistance exercise. The investigators randomly assigned healthy volunteers to one of the three groups: 1) 20 grams of casein; 2) 20 grams of whey protein; or 3) placebo (fake supplementation). Volunteers consumed the one drink one hour after the conclusion of a leg extension exercise bout.

As expected, this study showed that both casein and whey protein ingestion after resistance training resulted in positive amino acid balance (i.e., anabolic state). However, there was no significant difference in amino acid balance in response to ingestion of casein and whey protein. Nevertheless, long-term studies are certainly needed before any conclusions can be drawn. It would be of some interest to study the long-term effects of protein hydrolysate-containing recovery drinks.

Short-Term HMB Supplementation: No Ergogenic Effects

            Dr. Jay Hoffman and co-workers at the College of New Jersey examined the effects of HMB on muscle damage and stress during high-intensity training. Twenty-six members of a collegiate football team were randomly assigned to either an HMB group (three grams per day) or a placebo group. Testing occurred before and at end of 10 days of football camp. During each testing session, subjects performed an anaerobic (high-intensity) power test and blood samples were obtained.

            The results indicated that short-term HMB supplementation doesn't improve anaerobic power or attenuate muscle damage. According to the authors, "The results of this study do not support previous research that have reported on the anti-catabolic properties and improved strength performance of HBM supplementation." It should be noted, however, that this was a very short-term study. If one would study the effects of anabolic steroids on performance for 10 days, one probably wouldn't notice any difference compared to the placebo.

            Myostatin Blocker Supplements Appear Ineffective

            Myostatin blocker supplements (e.g., cystoseira canariensis) have been marketed with claims that it binds to blood myostatin and inhibits it from its role as a negative regulator of muscle mass. So, Dr. Darryn Willoughby at Baylor University examined 12 weeks of cystoseira canariensis supplementation on blood myostatin and muscle strength and body composition. He randomly assigned 22 untrained men to a placebo or myostatin blocker (1,200 milligrams per day) group in a double-blind fashion. The subjects trained three times per week using three sets of six to eight repetitions at 85 to 90 percent of one repetition maximum. 

The results indicated that the myostatin blocker had no effect on blood myostation or muscle mass and strength. According to Dr. Willoughby, "We can only conclude that at the recommended dosage of cystoseira canariensis the myostatin-binding supplement used in this study is ineffective at preferentially increasing muscle strength and mass and decreasing fat mass." It´s my view, however, that more research is needed before firm conclusions can be drawn.

References

• 1. Koopman R et al. The combined ingestion of protein and free leucine with carbohydrate increases post-exercise muscle protein synthesis in vivo in male subjects. Am J Physiol Endocrinol Metab, (in press).
• 2. Tipton KD et al. Ingestion of casein and whey proteins result in muscle anabolism after resistance exercise. Med Sci Sports Exerc, 2004;36:2073-2081.
• 3. Hoffman JR et al. Effects of b-hydroxy b-methylbutyrate on power performance and indices of muscle damage and stress during high-intensity training. J Strength Conditioning Res, 2004;18:747-752.
• 4. Willoughby DS. Effects of an alleged myostatin-binding supplement and heady resistance training on serum myostatin, muscle strength and mass, and body composition. Int J Sports Nutr Exerc Metab, 2004;14:461-472.