Key Points

• Don’t believe the hype – most sports nutrition supplements do not work as advertised.
• If a supplement does work, particularly if it quickly increases muscle mass, it may contain prescription drugs or other banned substances, and be both illegal and potentially harmful.
• The most effective way to improve performance is to combine proper training with adequate rest, nutrition, and hydration. These basics may be boring, but nothing works better.

Introduction

The dietary supplements marketplace in the U.S. (estimated $24-25 billion annual sales for 2009) can be a wild and woolly environment, where junk-science products abound, benefit claims are not to be trusted, and truly efficacious supplements are tainted by their snake-oil brethren. That scenario is certainly the case with sports nutrition supplements, a sub-set of the overall dietary supplement market, which tempt athletes with promises of sleek, powerful bodies provoked by pills, potions, and powders.

Athletes and coaches are understandably willing to consider almost any idea that promises improved performance. New ideas involving sports equipment, training techniques, and nutritional interventions are often greeted enthusiastically by coaches and athletes, put into practice before ample testing has occurred, and touted anecdotally as the latest-and-greatest idea to hit the sporting world. While most scientists would advise a more cautious approach to integrating new ideas into an athlete’s training regimen, the fact of the matter is that coaches and athletes have always been — and will always be – the initial arbiters of proposed innovations. Coaches and athletes are exposed to a constantly churning mix of new ideas. In sports, most new ideas have a short lifespan; an idea that was once new is rapidly superseded by the next “improvement”. This is particularly so in the area of sports nutrition, where there has historically been a rapid and seemingly endless series of product introductions, some of which make remarkable claims for superior performance, at times accompanied by remarkable risks.

Bogus Science Is the Rule, Not the Exception

Confronted with a constantly changing array of sports nutrition products, the claims for which often appear to bear convincing scientific support, it is not surprising that athletes and coaches have difficulty distinguishing fact from fiction. This confusion is the result of the plethora of commercial products targeted at physically active people, the inability of government agencies to adequately regulate the claims made for such products, the rapid turnover of sports nutrition products in the marketplace, the unavoidable and considerable lag time in conducting relevant research, and the confusion resulting from product benefit claims that can not be substantiated. Although there is little doubt that some sports nutrition products provide demonstrable benefits when properly used (e.g., sports drinks, creatine, caffeine, post-exercise protein intake), the claims for other products and nutritional interventions are often dubious, ill-founded, unproven, or abysmally deficient of scientific merit.

Junk Science = False Claims = No Benefit

Popular health and fitness magazines contain multiple articles and dozens of advertisements on sports nutrition supplements. For athletes searching for a performance edge, the allure of sports nutrition supplements is omnipresent, especially considering the tantalizing benefit claims…

• “helps your body use oxygen more efficiently”
• “contains powerful cell-volumizing and recovery nutrients”
• “the most effective antioxidant nutrients”
• “increases muscle protein synthesis while increasing cell hydration”
• “help sculpt a leaner , firmer body”
• “increase levels of ATP”
• “intense androgenic compound increases muscle mass”
• “prevents muscle loss during training and dieting”
• “produces a highly anabolic environment”
• “produces immediate results in energy, size, strength, pumps, performance,mental focus, and training intensity”
• “improve strength and stamina during workouts”
• “increases lean muscle mass and promotes fat loss”
• “increase peak power output, mean body mass, and muscular performance”

Each of these product claims involves a structural or functional benefit that is testable through scientific experimentation. Although a few of these advertising claims are accompanied by scientific references, the vast majority are not. This observation is similar to that of Grunewald and Bailey (Sports Medicine 15:90-103, 1993) who evaluated the advertising claims for 624 products targeted at body builders. The products were associated with over 800 performance-related claims, the vast majority of which were unsubstantiated by scientific research. A 2009 article in Sports Illustrated (Epstein D, G. Dohrmann. What you don’t know might kill you. May 18, 2009) highlighted the risks associated with sports nutrition supplements, especially those that promise quick increases in strength and muscle mass.

Food First

The simple truth is that no sports nutrition supplement comes close to providing the performance benefits associated with consuming a varied, balanced diet, high in carbohydrate, and with adequate protein. During exercise, the ingestion of fluid, carbohydrate, and sodium provides the greatest performance reward. Following scientifically sound nutritional practices provides maximal benefits at minimal risk. The same can not be said for many sports nutrition supplements. A good resource for more information and recommendations on sports nutrition is the American College of Sports Medicine – American Dietetic Association – Dietitians of Canada joint position statement on nutrition and athletic performance (Med Sci Sports Exerc 109:709-731, 2009; www.acsm-msse.org).

Supplement Suggestions

Before deciding whether or not to use a sports nutrition supplement, an athlete should answer these questions:

• Is my diet all that it could be in terms of eating a variety of healthy foods, including at least 5 servings of fruits and vegetables each day?
• Am I consuming enough calories (energy) every day? Some athletes have a difficult time maintaining body weight and muscle mass over the course of the season. Progressive weight loss means loss of muscle mass and is a sure sign the athlete is not getting enough to eat.
• Am I getting enough carbohydrate in my diet to help keep my muscles optimally fueled? (Carbohydrate intake should be 6 g/kg/day; that’s 2.7 grams of carbohydrate per pound of body weight per day; a 180-lb athlete should consume roughly 400 grams of carbohydrate from a variety of foods and beverages each day.)
• Am I eating a snack containing carbohydrate and protein after each workout to help speed recovery and stimulate muscle growth and repair?
• Am I hydrating properly throughout the day, especially during training and competition?
• Am I getting enough rest during the day and at least 8 hours of sleep each night? Am I focused and working hard during every practice, paying close attention to my coach’s suggestions and instructions? Am I doing enough of the right type of strength training? What specifically do I want to accomplish by using a sports nutrition supplement? Can my coach recommend a Registered Dietitian (RD) who specializes in sports nutrition to help me optimize my diet and choose the right supplements?

The benefits provided by even the most effective nutrition supplements pale in comparison to performance benefits associated with meeting the fundamental goals of sports nutrition. For that reason, it makes little sense to spend money on supplements if the athlete is failing to meet the basic goals highlighted in the questions above.

Other things to keep in mind …

There is no assurance that a supplement purchased from a local health food store or a national nutrition chain is safe or effective.

NSF International is a company that tests supplements to ensure that the contents do not contain banned or dangerous substances and that the levels of ingredients are as declared on the labels. The NSF web site (www.nsfsport.com) lists the supplements that have passed the NSF certification program.

Although questions about building muscles still outnumber answers, scientists are gradually learning more about how changes in muscle mass and functional capacity take place. The picture that is emerging is both complex from a scientific perspective and helpful from a practical standpoint. To understand the complexity, it is important to keep in mind that regardless of the sport, athletes are exposed to a variety of different types of training, including endurance/aerobic training, sprint/anaerobic training, strength training, and flexibility training. In other words, athletes are exposed to a variety of different types of training stimuli, all of which provoke hundreds, if not thousands, of different signals within the body. These signals involve virtually every physiological system: neural, hormonal, cardiovascular, and immune systems in addition to cellular signals in muscles, tendons, cartilage, blood vessels, elastic tissue surrounding muscle, and satellite cells adjacent to muscle cells.

Hundreds of genes and proteins are involved in the hypertrophy of muscle cells, making it highly unlikely that any one pathway can account for the increase in muscle mass and force production that accompanies strength training. An increase in the cross-sectional area of a single muscle cell requires substantial changes across three categories of intracellular proteins: contractile proteins (e.g., actin, myosin, and their many protein constituents), structural proteins (e.g., titin, dystrophin, integrins, and others too numerous to mention), and regulatory proteins (e.g., protein kinases, transcription/translation factors, calcium-trafficking proteins, and many others.)

While the complexity of muscle hypertrophy may be overwhelming, the practical off- shoot is that overloading muscles during training sparks a wide cascade of signals not only within muscle cells but throughout the body that coordinate to increase the number of sarcomeres in parallel (sarcomeres being the smallest contractile units within muscle cells.) Consuming high-quality protein soon after strength training helps accelerate the gain in muscle mass by stimulating muscle protein synthesis and prolonging the duration of net positive protein balance. In some people, ingesting creatine augments muscle hypertrophy, perhaps by increasing the activation of muscle satellite cells, an essential element in how muscle cells hypertrophy.

Emerging research will undoubtedly shed light on how strength training programs can be optimized to provoke the greatest responses in strength and mass. For example, how much rest between sets of strength exercises will optimize strength gains? Is one-minute rest sufficient or does a longer rest period provide a greater opportunity to maximize the signals associated with building muscle? What is the optimal combination of sets and reps to build strength? Is that different from the combination required to maximize mass? Should strength-training exercise purposefully damage muscle tissue to stimulate the proliferation and integration of satellite cells? If so, how much damage is enough? How can strength training be designed to enhance the well-known neural contributions to rapid strength gain? How can diet and supplements best contribute to gains in strength and mass?

These and other important questions will eventually be answered, although it will take many years to do so. Coaches and athletes are constantly refining their training techniques and scientists continue to study how muscles respond to different types of training. Educational efforts that combine these common interests will help scientists refine their experimental approaches and help sports health practitioners and athletes alter their training and nutrition practices based upon emerging science. That is the goal of the conference, Building Muscle: Challenging Current Dogma, to be held in Chicago during the spring of 2010.