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scin, the cheese sticks have a nice amount of protein but that amount of fat will really slow down the digestion process which will delay getting those carbs and protein into your muscles that need to recover, I agree with Kris on this, I think chocolate milk is great but I would say if you could get chocolate skim milk that would be even better but it is hard to find a product like that unless you just mix your own, muscle milk and most of the other similar products unfortunately have some scary amounts of heavy metals in them (according to a consumer reports study)

Chocolate milk? No shit. What is it about the chocolate that makes it better for this then regular whit milk? Do they add protein? I drink about 2 gallons a week and I've been wondering if it was too much (I like milk).

heavyc wrote:scin, the cheese sticks have a nice amount of protein but that amount of fat will really slow down the digestion process which will delay getting those carbs and protein into your muscles that need to recover, I agree with Kris on this, I think chocolate milk is great but I would say if you could get chocolate skim milk that would be even better but it is hard to find a product like that unless you just mix your own, muscle milk and most of the other similar products unfortunately have some scary amounts of heavy metals in them (according to a consumer reports study)

Good point about the fat. I've just been eating the cheese in place of my 5:00 protein bar since it's the same amount of fat and protein but way less sugar.
For recovery I use Endurox. I sip the "pink juice" while working out but never really drink it directly after a workout. Could be placebo but I feel like it helps.

Decided to do some research....

Amino acid supplements and recovery from high-intensity resistance training.(Author abstract)(Report).

Journal of Strength and Conditioning Research 24.4 (April 2010): p1125(6).
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Author(s): Carwyn P.M. Sharp and David R. Pearson.

Abstract:

The purpose of this study was to investigate whether short-term amino acid supplementation could maintain a short-term net anabolic hormonal profile and decrease muscle cell damage during a period of high-intensity resistance training (overreaching), thereby enhancing recovery and decreasing the risk of injury and illness. Eight previously resistance trained males were randomly assigned to either a high branched chain amino acids (BCAA) or placebo group. Subjects consumed the supplement for 3 weeks before commencing a fourth week of supplementation with concomitant high-intensity total-body resistance training (overreaching) (3 x 6-8 repetitions maximum, 8 exercises). Blood was drawn prior to and after supplementation, then again after 2 and 4 days of training. Serum was analyzed for testosterone, cortisol, and creatine kinase. Serum testosterone levels were significantly higher (p <: 0.001), and cortisol and creatine kinase levels were significantly lower (p < 0.001, and p = 0.004, respectively) in the BCAA group during and following resistance training. These findings suggest that short-term amino acid supplementation, which is high in BCAA, may produce a net anabolic hormonal profile while attenuating training-induced increases in muscle tissue damage. Athletes' nutrient intake, which periodically increases amino acid intake to reflect the increased need for recovery during periods of overreaching, may increase subsequent competitive performance while decreasing the risk of injury or illness.

More to come...

Acute effects of chocolate milk and a commercial recovery beverage on postexercise recovery indices and endurance cycling performance.(Report).

Applied Physiology, Nutrition, and Metabolism 34.6 (Dec 2009): p1017(6). (4990 words)
Author(s): Kelly Pritchett, Philip Bishop, Robert Pritchett, Matt Green and Charlie Katica.

Abstract:

To maximize training quality, athletes have sought nutritional supplements that optimize recovery. This study compared chocolate milk (CHOC) with a carbohydrate replacement beverage (CRB) as a recovery aid after intense exercise, regarding performance and muscle damage markers in trained cyclists. Ten regional-level cyclists and triathletes (maximal oxygen uptake 55.2 [+ or -] 7.2 mL x [kg.sup.-1] x [min.sup.-1]) completed a high-intensity intermittent exercise protocol, then 15-18 h later performed a performance trial at 85% of maximal oxygen uptake to exhaustion. Participants consumed 1.0 g carbohydrate x [kg.sup.-1] x [h.sup.-1] of a randomly assigned isocaloric beverage (CHOC or CRB) after the first high-intensity intermittent exercise session. The same protocol was repeated 1 week later with the other beverage. A 1-way repeated measures analysis of variance revealed no significant difference (p = 0.91) between trials for time to exhaustion at 85% of maximal oxygen uptake (CHOC 13 [+ or -] 10.2 min, CRB 13.5 [+ or -] 8.9 min). The change in creatine kinase (CK) was significantly (p < 0.05) greater in the CRB trial than in the CHOC trial (increase CHOC 27.9 [+ or -] 134.8 U x [L.sup.-1], CRB 211.9 [+ or -] 192.5 U x [L.sup.-1]), with differences not significant for CK levels before the second exercise session (CHOC 394.8 [+ or -] 166.1 U x [L.sup.-1], CRB 489.1 [+ or -] 264.4 U x [L.sup.-1]) between the 2 trials. These findings indicate no difference between CHOC and this commercial beverage as potential recovery aids for cyclists between intense workouts.

Do ergogenic aids help or hinder athletic performance? A review of the scientific research and the safety concerns regarding some of today's most popular performance-enhancing dietary supplements.
IDEA Fitness Journal 4.8 (Sept 2007): p44(9). (4523 words)
Author(s): Ellie Huff and Dale Huff.


Almost daily, people ask fitness professionals about the latest and greatest dietary supplements that claim to enhance physical performance. Although it is outside the scope of practice of personal trainers and fitness instructors ever to recommend a particular ergogenic aid to anyone, clients want to know if these products produce the results promised in the ads. There is no denying that dietary supplementation is widespread, especially among professional and recreational athletes. Frankly, it can be overwhelming even for nutrition experts to keep up with all the news and scientific research on every supplement that joins the performance-enhancing arsenal.

In this article, we examine the current regulatory state of the dietary supplement market and define the different categories of these products. We also take an in-depth look at four popular dietary supplements in terms of their mechanisms of action, side effects, safety and legality.

Our hope is that the information presented here will give you more detailed knowledge of dietary aids in general. While fitness professionals are not permitted to prescribe dietary supplements to clients, it is possible for you to be a source of current and accurate knowledge about such issues.

CONCERNS ABOUT DIETARY SUPPLEMENTS

It is estimated that nearly 60% of all elite athletes use one or more dietary supplements (Schroder et al. 2002). And people appear to be using these supplements at an earlier age. Today, close to 45% of collegiate athletes consume one or more dietary supplements, most often multivitamin/mineral supplements and creatine (Beck et al. 2006; Jonnalagadda, Rosenbloom & Skinner 2001). The two critical questions most people ask about any dietary supplement are always the same: Is the product safe? And is it effective?

So who is tasked with determining the safety and efficacy of dietary supplements? In the past, the Food and Drug Administration (FDA) regulated dietary supplements under the classification of foods to ensure that these aids were safe for human consumption and that package labeling was truthful and not misleading. Unfortunately, that is no longer the case. In 1994, Congress enacted the Dietary Supplement Health and Education Act (DSHEA), which some experts say severely limits the FDA's ability to regulate these products (Barrett 2007). By reclassifying dietary supplements as a separate regulatory category from food and drugs, the DSHEA essentially expanded the types of products that could be marketed as supplements and allowed manufacturers to propagate misleading information to consumers about the effects of these aids (Barrett 2007). As a result, many ingredients used in dietary supplements are no longer subject to the pre-market safety evaluations required of ingredients contained in food or drugs. Many nutrition experts believe that the public is now more vulnerable, because under the DSHEA there is no requirement to prove claimed benefits of dietary supplements as there is with drugs; no requirement to show safety with acute or chronic administration; few provisions for quality assurance; and liberal labeling requirements in relation to claims made.

LACK OF QUALITY CONTROLS

Quality control (which can be quite poor or even nonexistent at many supplement companies) is a great concern for consumers, who are at risk of ingesting a contaminated dietary supplement or of not getting what they paid for in terms of product quantity and potency. Evidence suggests that their concern is well-founded. A few years ago, the International Olympic Committee (IOC) laboratory in Cologne, Germany, raised concerns when it reported the results of analyses carried out on several legitimate dietary supplements (Maughan 2001). While none of the tested supplements indicated on the product label that they contained steroids and none cited any safety warnings, the lab identified the presence of nandrolone, testosterone and other steroids (Maughan 2001).

When the same lab followed up this study with a larger survey involving 634 different product samples purchased from 13 countries around the world, the results were equally dire (Maughan 2001). They showed that 94 of the supplements (14.8% of the products analyzed) contained substances prohibited by the IOC. While the brand names of the tainted supplements were not published, the sampling included vitamins and minerals, protein supplements, creatine and other popular products (Maughan 2001).

To address this concern, the FDA has issued a new rule requiring manufacturers of dietary supplements to follow "current good manufacturing practices" (FDA 2007). The rule is designed to ensure that dietary supplements are produced in a "quality manner, do not contain contaminants or impurities, and are adequately labeled" (FDA 2007). While this is a positive development for consumers, the new requirement has a 3-year phase-in, which won't be complete until June 2010, according to the FDA. What's more, the new rule does not require manufacturers to prove the efficacy and safety of any dietary supplement. That's why consumers still need to remain vigilant about any supplements they use. Athletes, coaches, personal fitness trainers and other health providers must know of the inherent risks associated with taking any supplement, from a simple multivitamin to a purported performance-enhancing product.

DEFINING TERMS

The FDA legally defines a dietary supplement as follows: "a product that is intended to supplement the diet that bears or contains one or more of the following ingredients: a vitamin, a mineral, an herb or other botanical, an amino acid, a dietary substance for use by man to supplement the diet by increasing the total daily intake, or a concentrate, metabolite, constituent, extract or combination of these ingredients" (FDA 1995). Under the DSHEA, a dietary supplement is adulterated if it or one of its ingredients presents "a significant or unreasonable risk of illness or injury" when used as directed on the label, or under normal conditions of use (if there are no directions) (FDA 1995).

Dietary supplements are an umbrella for a wide range of products, including weight loss pills and substances that promise to increase physical performance. Ergogenic aids are a type of dietary supplements that can increase the capacity for bodily or mental labor, especially by eliminating fatigue symptoms. These aids fall into different categories: mechanical aids, nutritional aids, pharmacological aids, physiological aids and psychological aids (see "Ergogenic Aid Classifications" on page 46).

Nutritional ergogenic aids refer to substances that enhance performance and are either nutrients, metabolic byproducts of nutrients, food (plant extracts) or substances commonly found in foods (caffeine and creatine) that are provided in amounts more concentrated than normally occur in the natural food supply (Benardot 2006).

The following sections discuss some of the four most popular types of supplements used to enhance physical performance: caffeine, creatine, carnitine and amino acids.

CAFFEINE

Caffeine is one of the most widely consumed drugs in the world. Because it is cheap, medically safe and socially acceptable, it has become a popular ergogenic aid for athletes (Antonio 2004). What's more, it has recently been removed from the IOC's banned-substance list, which will likely make it even more widely used and available to athletes (Beck et al. 2006).

Caffeine works as a central-nervous-system stimulant and a muscle relaxant. There is much scientific research to suggest that caffeine is an effective ergogenic aid for increasing endurance exercise performance, anaerobic performance and muscle strength (Beck et al. 2006). The possible mechanism of action for the increase in endurance performance may lie in the fact that caffeine increases the concentration of free fatty acids (FFAs) in plasma; it is thought that this increased availability of FFAs may enhance the ability of the cell to use these fats as fuels in endurance-type low-intensity exercises (Spriet 1995).

There is also widespread research to prove the positive ergogenic effects of caffeine on endurance performance, either by increasing oxygen consumption or by improving performance times (Bell & McClellan 2003). One study found that caffeine had a positive impact on the performance of male distance runners: the group of caffeine drinkers who consumed 1.4 milligrams (mg) of caffeine per pound of body weight showed a 1.2% improvement in an 8K race (Birnbaum & Herbst 2004). Another study found that caffeine was equally effective during cycling bouts. In this case, caffeine ingestion significantly increased the riders' exercise time to exhaustion, and repeating the dose after exhaustive exercise was not necessary to maintain the ergogenic effect 5 hours later (Engels et al. 1999).

While studies on caffeine have previously shown its benefit for increasing endurance-exercise performance, new research is proving the aid's positive effects on anaerobic performance and muscle strength. For example, a recent study that examined whether caffeine could improve cyclists' times during a 1-kilometer sprint reported a 3.1% improvement with the caffeine group (Wiles et al. 2006). Another study reported a significant increase in 1-repetition maximum bench press for participants who took a caffeine supplement prior to exercise (Beck et al. 2006). Caffeine may be an effective supplement for increasing upper-body strength and could be used by elite athletes for competition or by recreational athletes for resistance training.

Before you reach for that cup of java, keep in mind that caffeine is not the answer to everyone's need for power or speed. It is unsuitable for growing children or adolescents, especially. There is also a body of research that has failed to show any positive effect, either aerobic or anaerobic, from consumption of caffeine (Ahrens et al. 2007; Crowe, Leicht & Spinks 2006; Lorino et al. 2006).

Safety/Side Effects of Caffeine

While caffeine is generally considered safe, it is important to note that there have been reports on caffeine toxicity. In one case, a 16-year-old male who ingested an estimated 6-8 grams (g) of caffeine manifested many of the adverse effects seen with acute caffeine ingestion, such as elevated blood glucose, tachycardia and agitation (Leson, McGuigan & Bryson 1988).

With caffeine, as with any drug or supplement, there is the potential for abuse and misuse. A recent cover story in U.S. News & World Report cited the increased use and abuse of caffeinated drinks such as Red Bull, especially among adolescents (Shute 2007). The growing appeal of high-octane energy drinks has had some officials concerned enough to act. The FDA recently sent a warning letter to Redux Beverages LLC of Las Vegas--the manufacturer of Cocaine Energy Drink--for marketing the beverage "as an alternative to an illicit street drug." The company's own website used the terms "cocaine--instant rush." [Editor's note: In early May, the product was pulled from shelves nationwide; the company reintroduced the drink under a new name in mid-June.]

Elsewhere, a high school in Colorado Springs, Colorado, recently banned a drink called Spike Shooter after two students were taken to the hospital complaining of nausea, vomiting and heart palpitations after drinking an 8-ounce can, which contains 300 mg of caffeine (Shute 2007).

With plenty of data now available about the ergogenic benefits of caffeine, it is highly likely that we will see more of these products flooding the market. Expect increased consumption of such drinks in the future.

CREATINE

Creatine is one of the most popular dietary supplements used to enhance athletic performance (Bemben & Lamont 2005). Creatine is synthesized from amino acids in the liver, pancreas and kidneys at a rate of 1g per day (g/dy). Creatine is also consumed in sources such as meat and fish. Skeletal muscle holds 95% of the 120-140 g creatine found in the body. In the muscle, creatine is converted into phosphocreatine, necessary for production of adenosine triphosphate (ATP), which provides an anaerobic source of energy (McArdle, Katch & Katch 1999).

JPEGF

Creatine ingested through supplementation is reportedly absorbed into the muscle exclusively by means of a creatine transporter, called CreaT1 (Schoch, Willoughby & Greenwood 2006). Phosphocreatine is the major source of muscle energy during any exercise bout lasting 2-30 seconds. The availability of phosphocreatine is believed to become a limiting factor during short bouts of high-intensity exercise. Therefore, it is thought that if more phosphocreatine is available via creatine supplementation, there will be a faster recovery of ATP, thus improving high-power activity. The ergogenic claims of creatine supplementation include increased strength, power output and changes in fat-free mass.

The most common loading program cited in the research is an initial loading phase of 20 g/dy for 5-7 days, followed by a maintenance phase of 3-5 g/dy for differing periods of time (1 week to 6 months) (Bemben & Lamont 2005). More recently, a new dosing strategy has been introduced, which is based on either total body mass or fat-free mass and which yields approximately 20 g/dy (Schoch, Willoughby & Greenwood 2006). This strategy suggests that creatine uptake will differ in regard to differences in muscle mass, perhaps owing to the CreaT1 uptake mechanism. It is thought that CreaT1 activity is lower in certain people known as "nonresponders." A study that compared the traits of creatine supplement responders and nonresponders found that responders generally

* had lower initial quantities of intramuscular creatine and were able to absorb and take up greater amounts via supplementation;

* had a greater percentage of type II muscle fibers;

* had larger muscle fiber cross-sectional areas; and had more fat-free mass than the nonresponders (Syrotuik & Bell 2004).

These findings suggest that the efficacy of creatine supplementation may lie in one's biological profile.

Scientific studies have consistently demonstrated the efficacy of creatine supplementation for increasing muscular strength, power output and body mass during short, repeated bouts of maximal exercise in healthy, untrained young adults (Bemben & Lamont 2005; Greenwood et al. 2000; Schoch, Willoughby & Greenwood 2002). However, about half of all the published research on creatine has failed to show any ergogenic effect in this population. Specifically, creatine supplementation does not appear to enhance endurance activities.

Since it has been fairly well established that creatine does increase muscular strength and power in healthy young males, researchers are now turning to other populations to determine whether creatine improves their physical performance as well. One study tested the effect of 2 and 5 days of creatine loading on anaerobic working capacity in women athletes vs. a placebo group; results showed an increase in anaerobic work capacity of 22% after the 5-day loading phase (Eckerson et al. 2004).

So what are the practical ramifications of taking creatine to improve physical performance? According to lay Hoffman, PhD, a professor at The College of New Jersey, "The efficacy of creatine supplementation has been well established in an athletic population. However, there need to be some additional studies examining various loading schemes and appropriate intake amounts for individuals of varying body masses and age ranges."

Safety/Side Effects of Creatine

JPEGF

The safety of creatine has been hotly debated. Although the general consensus is that creatine is safe, there is scant evidence on its effect in adolescents or the ramifications of its long-term use. Anecdotal reports of the side effects of creatine supplementation include gastrointestinal disturbances, muscle cramps, weight gain and nausea (Leson, McGuigan & Bryson 1988).

Research continues to support the use of creatine for improved performance, but results may vary depending on the individual's biological profile. Appropriate dosing strategies should be implemented to increase the potential benefits and reduce any possible side effects. Adding creatine to a carbohydrate source has been observed to enhance uptake via an insulin response (Green et al. 1996).

CARNITINE

Carnitine is another popular ergogenic aid used by consumers. Manufacturers claim that carnitine supplements can decrease muscle pain and increase weight loss, endurance, cardiovascular function and strength.

L-carnitine was first discovered in muscles in the early 1900s. Carnitine plays a critical role in energy production; it transports long-chain fatty acids into the mitochondria cells so they can be burned to produce energy. Approximately 95% of the body's carnitine stores are in the skeletal and cardiac muscle (Fragakis 2003). Carnitine occurs in two forms, known as D and L, which are mirror images of each other. Only L-carnitine is active in the body and is the form found in food.

Healthy adults and children do not need to consume carnitine from food or supplements, because the liver and kidneys produce sufficient amounts from the amino acids lysine and methionine to meet their daily needs.

While more and more athletes are turning to carnitine to improve performance, there is no consistent evidence that carnitine supplements can enhance exercise or physical performance in healthy subjects. However, recent studies have found some improvements in recovery from resistance exercise when carnitine is taken at a dose of 1-2 g/dy (Spiering et al. 2007).

Safety/Side Effects of Carnitine

No serious adverse effects have been reported with carnitine doses ranging from 0.5-0.6 g/dy (Fragakis 2003). Most study protocols have used an oral dose of 2-4 g/dy, which is the typical recommendation from manufacturers. Higher doses (i.e., more than 6 g/dy) have been associated with nausea and diarrhea (Fragakis 2003).

AMINO ACIDS

It has been well documented that endurance- and strength-trained athletes need more protein than their more sedentary counterparts. However, it has been equally well documented that this increased protein intake can be achieved through diet alone.

To clarify these needs, the American Dietetic Association (ADA), the Dietitians of Canada (DC) and the American College of Sports Medicine (ACSM) co-wrote and released a joint Position Paper on nutrition and athletic performance in which they recommended that strength athletes consume 1.6-1.7 g protein per kilogram of body weight (kg/bw) and that endurance athletes need 1.2-1.4 g protein/kg/bw (ADA, DC & ACSM 2000).

But since amino acids (AAs) are the building blocks of protein, can taking an AA supplement help with muscle building? With 20 different amino acids in dietary protein, researchers have been working overtime to determine whether specific amino acids can help prevent fatigue, act as an ATP-sparing mechanism during exercise, increase the secretion of anabolic hormones or reverse/prevent the effects of overtraining.

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One study did find a net positive increase in muscle protein balance in subjects who consumed about 0.1 g of essential amino acids per kg/bw during the first few hours of recovery from heavy resistance exercise (Gibala 2002). According to one researcher, providing an ample supply of essential amino acids to the muscle 1-3 hours before or after exercise may help to further muscle protein synthesis (Williams 2005).

Amino acid cocktails seem to be a topic of current research; scientists are mixing AAs with protein, carbohydrate and other ergogenic aids, such as creatine, to see if there is enhanced benefit.

Due to space constraints, we cannot address all AAs. Instead, we'll focus on a few of the most popular: branched-chain amino acids, glutamine and arginine.

Branched-Chain Amino Acids

Isoleucine, leucine and valine make up what are known as the branched-chain amino acids (BCAAs), a group of essential amino acids that have been studied for their potential role in delaying central-nervous-system fatigue in athletes. However, much of the existing research on BCAAs is inconclusive, and more studies are needed to determine the mechanism of action, efficacy and safety of these AAs.

Glutamine

Glutamine is a nonessential amino acid, meaning that it can be produced in the body; it is also the most abundant free amino acid in skeletal muscle and plasma. The rationale for glutamine's use as an ergogenic aid comes from a study that found that this AA effectively counteracted protein synthesis decline and muscle wasting from repeated use of glucocorticoids (McArdle, Katch & Katch 1999).

During times of stress, the body's need for glutamine can exceed its supply. This has led scientists to theorize that supplemental glutamine may help with recovery from the stress of exercise. However, research on glutamine supplementation has not yielded convincing evidence that this product provides any ergogenic effect.

Arginine

Arginine is a nonessential amino acid involved in the synthesis of urea in the liver. However, during periods of growth the body may need more arginine than is available because arginine is thought to stimulate the secretion of anabolic hormones, such as human growth hormone (HGH) and insulin (Fragakis 2003). Given its apparent role in increasing HGH levels, arginine may possibly enhance muscle building. At this time, it remains unclear whether arginine supplementation has any true ergogenic benefit. However, some studies have shown that arginine may hold promise for wound healing and for improving cardiovascular health in patients with heart disease.

Safety/Side Effects of Amino Acids

Individuals who are prone to kidney stones or at risk for kidney disease should consult their physician prior to increasing the amount of protein in their diet. While most AA supplements are considered safe, any supplement is subject to impurities or to the lack of quality assurance mentioned earlier.

SUPPLEMENT SUMMARY

This article did not set out to cover the full breadth of research available on each supplement highlighted. Rather, the purpose was simply to provide a general understanding of the current research on different dietary supplements; to explain the lack of government regulation; and to issue the reminder that fitness professionals need to stay within their scope of practice when it comes to discussing ergogenic aids with clients. That said, it is important for fitness professionals to be able to discuss these aids in an educated and impartial manner, if only to remind clients of the potential dangers and ramifications of supplement use.

So, now you guys can make some educated decisions on your supplements for recovering GL!

Ok, maybe one or two more...

Dietary Supplements and Sports Performance: Amino Acids.(Commentary).

Journal of the International Society of Sports Nutrition 2.63 (Dec 9, 2005): p63(5). (3226 words)
Author(s): Melvin Williams.



Abstract:

This is the third in a series of six articles to discuss the major classes of dietary supplements (vitamins; minerals; amino acids; herbs or botanicals; metabolites, constituents/extracts, or combinations). The major focus is on efficacy of such dietary supplements to enhance exercise or sport performance.

Full Text :
COPYRIGHT 2005 BioMed Central Ltd.

Authors: Melvin Williams (corresponding author) [1]

Dietary Protein and Protein Supplements

Protein is one of the most popular dietary supplements marketed to athletes and physically-active individuals. Protein supplements have been recommended to athletes to enhance nitrogen retention and increase muscle mass, to prevent protein catabolism during prolonged exercise, to promote muscle glycogen resynthesis following exercise, and to prevent sports anemia by promoting an increased synthesis of hemoglobin, myoglobin, oxidative enzymes, and mitochondria during aerobic training. However, whether or not athletes need more protein is currently debatable. Based on available research, the American College of Sports Medicine, the American Dietetic Association, and the Dietitians of Canada, in their recent joint position stand on nutrition and athletic performance [1], concluded that protein requirements are higher in very active individuals and suggested that resistance athletes need 1.6-1.7 g protein/kg body weight while endurance athletes need approximately 1.2-1.4 g protein/kg, values that are about 150-200 percent of the current United States Recommended Dietary Allowances (RDA). Conversely, in its recent presentation of the Dietary Reference Intakes (DRI) for protein, the National Academy of Sciences [2] concluded that in view of the lack of compelling evidence to the contrary, no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise. Sports nutrition scientists do note that even if athletes need more protein, the recommended amounts are compatible with the current Acceptable Macronutrient Dietary Recommendations (10-35 percent of energy from protein) and may be easily obtained from natural foods in the diet [3, 4]. In general, protein supplements are not necessary [5, 6].

However, dietary protein is composed of 20 different amino acids which, if ingested individually, have been theorized to possess ergogenic potential and have been marketed as sports supplements to physically active individuals. Indeed, amino acids are among the top five most popular sports supplements [7].

Amino Acids: Ergogenic Theory

Amino acids are theorized to enhance performance in a variety of ways, such as increasing the secretion of anabolic hormones, modifying fuel use during exercise, preventing adverse effects of overtraining, and preventing mental fatigue. The following discussion highlights research regarding the ergogenic effects of individual amino acids, various combinations of amino acids, and several special protein dietary supplements.

Tryptophan

Tryptophan (TRYP), is a precursor for serotonin, a brain neurotransmitter theorized to suppress pain. Free tryptophan (fTRYP) enters the brain cells to form serotonin. Thus, tryptophan supplementation has been used to increase serotonin production in attempts to increase tolerance to pain during intense exercise. One study reported significant improvements in time to exhaustion at 80 percent of maximal oxygen uptake, accompanied by significant reductions in the rating of perceived exertion [8]. However, research with a more appropriate experimental design did not replicate these findings [9]. Moreover, other investigators reported no effect of TRYP supplementation on aerobic endurance performance at 70-75 percent of maximal oxygen uptake [6]. Tryptophan does not appear to be an effective ergogenic [10].

Branched chain amino acids (BCAA)

Some investigators believe that increased levels of serotonin may cause fatigue [11]. During prolonged aerobic endurance exercise, muscle glycogen may become depleted and the muscle may increase its reliance on BCAA for fuel, decreasing the plasma BCAA:fTRYP ratio. Because BCAA compete with fTRYP for entry into the brain, a low BCAA:fTRYP ratio would facilitate the entry of fTRYP to the brain and the formation of serotonin. Hypothetically, BCAA supplementation may delay central nervous system fatigue and enhance performance in prolonged aerobic endurance events by increasing the BCAA:fTRYP ratio and mitigating the formation of serotonin.

BCAA supplementation has been studied for its effects on various types of exercise performance, including ratings of perceived exertion (RPE) during exercise and mental performance following exercise. In general, the findings are equivocal, as are the conclusions from several recent reviews. One investigator concluded that BCAA supplementation reduces RPE and mental fatigue during prolonged exercise and improves cognitive performance after exercise, and also suggests that in some situations BCAA supplementation may improve physical performance, such as during exercise in the heat or in actual competitive races where central fatigue may be more pronounced than in laboratory experiments [12]. However, other reviewers conclude that most studies show no effects of BCAA supplementation on performance, such as prevention of fatigue during prolonged exercise [13, 14] two recent studies support these conclusions. Watson and others [15] reported no beneficial effects of BCAA supplementation, consumed before and during prolonged cycling to exhaustion at 50 percent VO2 max in the heat, on performance time, heart rate, and core or skin temperature. Cheuvront and others [16] reported similar findings with subjects exercising in the heat, noting no significant effect of BCAA supplementation on time-trial performance, cognitive performance, mood, perceived exertion, or perceived thermal comfort. Although current research does not support an ergogenic effect of BCAA supplementation, most investigators recommend additional research.

Glutamine

Glutamine may be theorized to be ergogenic in various ways [6]. It is an important fuel for some cells of the immune system, such as lymphocytes and macrophages, which may be decreased with prolonged intense exercise, such as that related to overtraining. Glutamine may also promote muscle glycogen synthesis, and has been studied for potential enhancement of muscular strength.

Several investigators theorize that athletes who overtrain may experience decreased plasma glutamine levels, which may impair functions of the immune system and predispose the athlete to various illnesses [17, 18]. Illness may impair training and eventual performance. Research findings are equivocal, with some studies reporting lower incidence rates of infection among athletes who consumed a glutamine-supplement drink following intense training [19]. However, others reported that although glutamine supplementation helped maintain plasma glutamine levels following intense exercise, it had no effect on various tests of the immune response [20]. Recent reviews indicated that there is little support from controlled studies to recommend glutamine ingestion for enhanced immune function [14, 21].

Although glutamine may simulate muscle glycogen synthesis, reviewers recently concluded that there is no advantage over ingestion of adequate carbohydrate alone [14]. Moreover, several recent studies indicate that neither short-term nor long-term glutamine supplementation has an ergogenic effect on muscle mass or strength performance. Glutamine supplementation one hour prior to testing had no effect on resistance exercise to fatigue, nor did six weeks of glutamine supplementation during resistance training increase lean muscle mass or strength more so than the placebo treatment [22, 23].

Aspartates

Potassium and magnesium aspartates are salts of aspartic acid, an amino acid. They have been used as ergogenics, possibly by enhancing fatty acid metabolism and sparing muscle glycogen utilization or by mitigating the accumulation of ammonia during exercise. The effect of aspartate supplementation on physical performance is equivocal, but about 50 percent of the available studies have indicated enhanced performance in exercise tests of aerobic endurance [6]. Additional research is needed to study the potential ergogenicity and underlying mechanisms of aspartate salt supplementation.

Arginine

Arginine supplementation may be theorized to be ergogenic because it is a substrate for nitric oxide (NO) synthesis, a potent endogenous vasodilator that may benefit blood flow and endurance capacity. Several studies involving patients with peripheral arterial disease or clinical symptoms of stable angina pectoris have shown improved exercise capacity with arginine supplementation [24, 25]. However, research involving the independent effect of arginine supplementation on the aerobic endurance capacity of healthy athletes has not been uncovered [6].

Ornithine, lysine and arginine

Ornithine, lysine and arginine have been used in attempts to increase human growth hormone (HGH) production, the theory being to increase lean muscle mass and strength. However, although limited data are available, a number of well-controlled studies, several with experienced weight lifters, reported no increases in HGH levels or various measures of muscular strength or power [26, 27, 28].

Chromiak and Antonio [29] reviewed the scientific studies on growth-hormone releasing amino acids (ornithine, lysine and arginine) and indicated that oral doses that are great enough to induce significant growth hormone release are likely to cause gastrointestinal discomfort. Moreover, they reported that no studies found that pre-exercise oral amino acid supplementation augments growth hormone release. They also concluded that no appropriately conducted scientific studies found that oral supplementation with such amino acids before strength training increases muscle mass and strength to a greater extent than strength training alone. They do not recommend the use of specific amino acids to stimulate growth hormone release.

Tyrosine

Tyrosine is a precursor for the catecholamine hormones and neurotransmitters, specifically epinephrine, norepinephrine, and dopamine. Some have suggested that inadequate production of these hormones or transmitters could compromise optimal physical performance. Thus, as a precursor for the formation of these hormones and neurotransmitters, tyrosine has been suggested to be ergogenic. However, in a well-designed placebo-controlled, crossover study, Sutton [30] and others found that tyrosine supplementation (150 milligrams/kilogram body weight) consumed 30 minutes prior to taking a series of physical performance tests significantly increased plasma tyrosine levels, but had no significant ergogenic effects on aerobic endurance, anaerobic power, or muscle strength.

Taurine

Taurine is a non-essential sulfur-containing amino acid, but it lacks a genetic codon to be incorporated into proteins or enzymes. Nevertheless, it plays a role in several metabolic processes, such as heart contraction and antioxidant activity. Taurine is an ingredient in several so-called energy drinks , such as Red Bull.

Baum and Weiss [31] reported that Red Bull, which contains taurine and caffeine, as compared to a similar drink without taurine, favorably influence cardiac parameters, mainly an increased stroke volume, during recovery after exercise; however, physical performance was not tested. However, Zhang and others [32] reported that 7 days of taurine supplementation induced significant increases in VO2 max and cycle ergometer exercise time to exhaustion; the ergogenic effects were attributed to taurine's antioxidant activity and protection of cellular properties.

Amino Acid Cocktails

Providing an ample supply of essential amino acids to the muscle within 1-3 hours before or following exercise may help to further muscle protein synthesis. Gibala [33] indicated that consumption of a drink containing about 0.1 gram of essential amino acids per kilogram of body weight (7 grams for a 70-kilogram athlete) during the first few hours of recovery from heavy resistance exercise will produce a transient, net positive increase in muscle protein balance. Gibala also noted that it is uncertain if ingesting amino acids, either alone or combined with carbohydrate, immediately before exercise or during recovery further enhances the rate of muscle protein buildup during recovery. Some investigators have suggested that it may be helpful to consume, throughout the day, multiple small meals having adequate protein. Gibala indicates that although these strategies will promote a net "anabolic" environment in the body, it remains to be determined if the acute effects of supplementation eventually lead to greater gains in muscle mass following habitual training. Others also note that small amounts of amino acids, combined with carbohydrates, can transiently increase muscle protein anabolism, but it has yet to be determined if these transient responses result in an appreciable increase in muscle mass over a prolonged training period [42, 34].

Overall, given these findings, consuming a small amount of protein and carbohydrate, either as a protein/carbohydrate energy drink or whole foods, before or after exercise training may be prudent behavior for many athletes.

Whey Protein and Colostrum

Whey and colostrum are two forms of protein that are theorized to be ergogenic. Whey proteins are extracted from the liquid whey that is produced during the manufacture of cheese or casein, while colostrum is the first milk secreted by cows. Both are rich sources of protein, vitamins and minerals, but may contain various biologically active components, including growth factors [35, 36]. Although no mechanism has been identified, one theory involves increased levels of serum insulin-like growth factor (IGF-1), which could be anabolic. However, research with colostrum supplementation shows no effect on blood IGF-I or IGF binding protein levels [37].

Research regarding the ergogenic effect of whey protein and colostrum supplementation is very limited [6]. In general, research findings are equivocal. For example, one study evaluated the effect of colostrum supplementation on four tests of exercise performance and reported a significant effect on 50-meter sprint time, but no effect on vertical jump, shuttle sprinting to exhaustion, or 300-meter sprint time [38]. Brinkworth and others [39] reported that bovine colostrum supplementation, as compared to whey protein, during 8 weeks of resistance training group increased arm circumference and cross-sectional area, but the increase was due principally to a greater increase in skin and subcutaneous fat. Tipton and others [40] reported that acute ingestion of both whey protein and casein after exercise resulted in similar increases in muscle protein net balance, resulting in net muscle protein synthesis despite different patterns of blood amino acid responses. Although the results of these studies were suggestive of ergogenic effects, they should be regarded as preliminary and more research is merited.

Safety, Legality

Consumption of high-protein diets (2.8 g protein/kg or less) by well-trained athletes does not appear to impair renal function, as indicated by various measures of renal function [41]. However, certain individuals should be concerned with the protein content in their diet, such as those with diabetes mellitus predisposed to kidney disease, and those prone to kidney stones [6]. Most amino acid supplements are safe in recommended dosages, but may interfere with protein metabolism if consumed in excess. Use of amino acid supplements is not prohibited by the World Anti-Doping Agency (WADA).

Researchers discover honey is good for muscles. (Clinical Innovations).(Brief Article).

AORN Journal 74.4 (Oct 2001): p516(1). (159 words)


Researchers at the University of Memphis have discovered that honey may be beneficial to muscles, according to a news story from bshealthwatch.medscape.com. Previous studies found that a combination of carbohydrates and protein supplements boosts muscle recovery, but these studies did not examine what type of carbohydrates were most beneficial. Researchers at the University of Memphis used honey as a carbohydrate source and combined it with a protein supplement. They found that athletes maintained better glucose levels with this combination, which is important to postworkout recovery.

Thirty-nine weight-trained athletes participated in the study. They completed an intensive weight-lifting workout then immediately consumed a protein supplement blended with sugar, maltodextrin, or honey. Only those subjects in the honey group maintained optimal blood sugar levels two hours after the workout, and they also showed favorable changes in hormone ratio, indicating positive muscle recuperative status.

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