Jan 29, 2015
Choices … And More Choices

As the number of nutritional supplements on the market keeps growing, athletes can easily get lost among the choices. Our expert explains how to steer clear of unwanted risks and toward real performance gains.

By Michelle Rockwell

Michelle Rockwell, MS, RD, CSSD, is a private sports nutrition consultant based in Durham, N.C. She works with athletes and teams throughout the country ranging from recreational to professional. She also offers sports nutrition consulting and workshops through RK Team Nutrition, at: www.rkteamnutrition.net.

Last year, I was sitting in my office with an elite-level swimmer–a former and likely future Olympian–who was in the midst of her most intense training phase of the year. She was telling me about how she had stopped using all types of sports drinks, sports bars, and recovery shakes, and had even thrown away the multivitamin, vitamin C, glucosamine/chondroitin, and omega-3 fatty acid supplements she had been taking as part of our performance nutrition plan. Since the plan had helped her record a tremendous season the previous year, I was very surprised.

The change was spurred by a presentation she’d heard at a recent training camp about the risks of supplement contamination. An athlete had discussed his experience being banned from competition for two years after testing positive for a steroid, even though he had never taken steroids: He had unknowingly used contaminated nutritional supplements. The athlete ultimately won a lawsuit against the manufacturer, but no one could repay him those two lost years of competing. That story was enough to make my swimmer swear off everything–even her Gatorade.

It’s true that the supplement world can involve considerable risks and plenty of unknowns, including–though certainly not limited to–contamination. But it’s also true that when used responsibly, supplements can help athletes achieve their performance goals. The problem is athletes often have a hard time separating fact from fiction and legitimate claims from marketing hype. And the ever-growing whirlwind of aggressive advertising, confusing research, and anecdotal peer experience does little to help.

That’s where you come in. In this article, I’ll discuss how to evaluate nutritional supplements so that you can provide meaningful advice to your athletes when it comes to choosing safe, legal, and effective products. I’ll also review some popular supplements and suggest natural dietary alternatives.

Breaking It Down

Today’s nutritional supplement marketplace is largely a “buyer beware” environment. Supplements are not regulated by the Food and Drug Administration (FDA), so there is no required testing for safety and effectiveness before a product hits the shelves. And many supplement makers see athletes as a prime target, as claims about boosting energy, reducing body fat, and building strength and power find an eager audience among those looking for a competitive edge.

Let’s say an athlete comes to you with a supplement brochure, a printout from the Web, or a bottle of some supplement they’re interested in taking. They want your advice. What do you do? I recommend breaking the evaluation process down into four key criteria.

Legality: It may sound obvious, but the first thing to look at is whether a supplement is legal. You probably know, for instance, that anabolic steroids are illegal to purchase in the U.S., but they can easily be found online. Androstenedione (“andro”) and other prohormones (sometimes called “testosterone precursors”) have been illegal since the passage of the Anabolic Steroid Control Act of 2004. Other substances, such as ephedrine, may be legal to purchase over the counter, but their sale is regulated by the FDA.

Beyond actual laws, there’s also the question of whether a supplement is banned by a sports governing body. The NCAA and International Olympic Committee (IOC) each maintain lists of banned substances, as do most professional sports leagues. The lists are updated as new products hit the market, so always make sure you’re using the most current version when checking on the permissibility of an ingredient or a supplement.

Purity: In studies evaluating large numbers of over-the-counter dietary supplements, it is consistently shown that 15 to 25 percent of products tested contain ingredients not listed on the label. Some of those ingredients are banned by the NCAA and/or the IOC.

Ingredients found in supplements but not listed on labels often include prohormones or actual steroidal ingredients, stimulants, or even heavy metals such as lead. And unfortunately, “I didn’t know the supplement was tainted” is rarely an acceptable excuse if a drug test comes back positive.

Sometimes the contamination of a supplement is deliberate, and sometimes it’s simply the result of poor manufacturing practices. For instance, if a company makes multiple products, some of which contain banned ingredients, contamination can occur if the mixing machines are not properly cleaned between manufacturing runs.

How do you know if a manufacturer can be trusted? To address concerns about the purity of commercially available products, independent labs and certification bodies have been created to evaluate supplements and verify that their labels are complete and accurate. Supplements certified by these groups are more trustworthy than those that have not been submitted for independent testing. (See “Resources” below for links to these groups’ Web sites.)

Safety: I recently worked with a high school football player who was referred to me after a scary experience. During practice, he had developed a severe headache and a rapid heart rate and had to be rushed to the emergency room. His physicians felt the symptoms were related to stimulant supplements and NO2 (an arginine-based product).

Supplements can raise safety concerns for several reasons. In this case, I believe the effects from the supplements were compounded by poor hydration. Most athletes don’t know that muscle-building supplements often increase the body’s fluid needs, and some stimulants have been shown to increase the risk of heat stress. Add in the fact that athletes often use these products during periods of heavy activity, and the risk for dehydration and heat illness is very real.

Another serious concern is interaction between different supplements, or between supplements and medications an athlete may be taking–both prescription and over the counter. In some cases, a supplement can enhance the effect of a medication or vice-versa. In other cases, the effectiveness of one or both substances is reduced.

For example, dietary supplements containing St. John’s Wort, a popular ingredient used to treat depression, may negate the effects of some antibiotics and birth control pills. Willow bark (the herbal equivalent of aspirin) in dietary supplements typically enhances the effects of other ingredients, especially stimulants such as caffeine, guarana, and synephrine. Stimulants and prohormone supplements may interact with antidepressants and anti-anxiety drugs, and with medications taken for learning disabilities. Ginseng, ginkgo, and high doses of vitamin E have blood-thinning effects and may be hazardous to athletes set to undergo surgery.

The best way to avoid potentially harmful interactions between dietary supplements and other drugs is to bring a physician into the picture. Make sure athletes disclose any medications they are taking before you recommend a supplement, and check with their doctor or a team physician about the risk of any unwanted side effects.

Efficacy: How do you know if a supplement will deliver on its promises? That’s a difficult question, since many products–even effective ones–have not undergone the controlled experiments necessary for ironclad conclusions. And athletes’ own experience may be colored by the placebo effect (they expect it to work, so they believe it is working).

At minimum, it’s important to discuss with an athlete what the supplement’s desired effect is, and whether that desire is consistent with his or her performance, body composition, and health goals. Remarkably, athletes often take a dietary supplement without being able to say exactly what they hope it will do for them.

Athletes should also understand that people respond to supplements differently. Some individuals, for example, are very sensitive to caffeine, while others feel little effect from it. Sensitivity can also vary by day, diet, activity level, or hydration status. A popular example of this phenomenon involves creatine: It increases muscle phosphocreatine levels for some people (“responders”), but not for others (“non-responders”). If an athlete tries a supplement and doesn’t experience the desired effect, it may simply not be the right fit for their biochemistry or lifestyle.

Getting Specific

Keeping up with every new supplement that comes out is a tall order. But it’s important to be well versed on those that are most popular with athletes right now. Below I will discuss these categories of products and offer a few suggestions on when (or if) they are appropriate to recommend.

Creatine, now available in many formulations, remains a very popular seller with athletes. It has been shown to increase some people’s levels of muscle phosphocreatine, a substance that breaks down to produce adenosine triphosphate (ATP, an energy source). Theoretically, higher phosphocreatine stores help speed recovery, improve high-intensity performance, and build lean body mass, and those results have been found in numerous studies.

Many athletes don’t realize that creatine occurs naturally in food. Beef, pork, and fish such as salmon and cod all contain about one gram of creatine per eight ounces–about a third of the recommended daily dose for supplementation. Thus, eating three eight-ounce servings of these foods per day can provide a standard supplemental dose of creatine without the supplement. Poultry is lower in creatine, so athletes who always choose chicken and turkey should be encouraged to diversify their menus. Vegetarians eat few creatine-containing foods, so they may benefit most from creatine supplementation.

Here’s another key nutritional note: The phosphocreatine system only contributes to energy production in the first few seconds of muscle activation. After that, carbohydrates become the primary fuel source. Thus, if dietary carbohydrate intake is insufficient, creatine’s benefits will be short-lived.

Who should avoid creatine supplementation? Because it leads to increased fluid needs, it’s a bad choice for athletes who are prone to cramping, heat illness, or easy muscle pulls. Athletes working out in hot environments and those who sweat excessively should also steer clear of creatine.

Protein and amino acids are commonly used by athletes seeking to gain weight. Recently, there has been a focus on the source of protein used in supplements (whey vs. casein vs. soy vs. egg), as some researchers feel whey protein leads to greater lean body mass gains, but this has not been conclusively established.

Athletes have used amino acid supplements for years, though there is little research to support their benefits. Two possible exceptions are glutamine, which some studies show improves immune function and recovery, and branched-chain amino acids (BCAAs), which may be beneficial during very long exercise periods when muscle protein is oxidized for fuel.

Protein supplements are a convenient choice for athletes who don’t get enough protein through their normal diet. The American Dietetic Association and American College of Sports Medicine (ACSM) recommend a protein intake of 1.2 to 1.7 grams per kilogram of body weight per day, and most athletes can achieve this through eating meat, poultry, fish, dairy products, eggs, nuts, seeds, beans, and grains. Consistently selecting a variety of protein sources helps ensure adequate levels of all amino acids. Glutamine and BCAAs in particular are plentiful in many types of foods, especially dairy products and red meat.

Beta-alanine is a newer supplement that’s very popular right now. This specific amino acid is involved in carnosine production, which plays a role in buffering acid in muscle cells. Consequently, these supplements promise “decreased muscle burn” and delayed fatigue during high-intensity exercise. There are now some studies supporting those claims, but this supplement warrants further research before its benefits (and any potential risks) are clearly established.

The advertised benefits of beta-alanine can be achieved much more reliably through simple dietary changes. Athletes who experience excessive muscle burn during activity are often underhydrated, so they should be encouraged to drink more before, during, and after exercise. And the consumption of quality carbohydrates before workouts will delay fatigue considerably. Suggest that athletes try these solutions before turning to a supplement that still has some question marks.

Nitric oxide (NO or NO2) is derived from the amino acid arginine. These supplements are marketed as enhancing “muscle pump,” vasodilation, and blood and nutrient delivery to muscles. Many athletes say they like the way nitric oxide makes them feel before and during workouts.

But a growing number of sports medicine professionals have observed troubling side effects from NO and NO2 supplementation, such as extreme headaches, lightheadedness, and increased blood pressure. There is currently very little research to support the purported benefits or assess the risk of side effects. Until that changes, I discourage athletes from using these supplements.

Good hydration and adequate intake of vitamins and minerals are critical for proper nutrient delivery to muscles. If an athlete is tempted by the claims of nitric oxide, try evaluating their hydration habits and vitamin and mineral intake instead, and they may experience surprising performance benefits.

Energy supplements come in many forms: drinks, pills, powders, bars, and even special gums and candies. They promise to enhance energy and boost metabolic rate, thereby leading to fat loss. Some contain substances such as synephrine, bitter orange, citrus aurantium, and zhi shi, all of which are banned by the NCAA.

Other products contain stimulants that are permissible in limited does, such as caffeine, guarana, and green tea extracts. Some research supports the use of caffeine for enhancing athletic performance, but it affects individuals differently–some experience dehydration, rapid heartbeat, jitteriness, and laxative effects from caffeine and other stimulants.

Why are athletes drawn to this “artificial” energy boost? It’s often a sign of inadequate caloric intake, low glycogen stores, poor hydration habits, not getting enough sleep, iron deficiency, overtraining, or possibly a mental health issue. You should help athletes consider all those areas before thinking about an energy supplement–if one of them is the underlying cause, addressing it will have much more lasting effects than a stimulant.

If you do want to recommend an energy supplement, I suggest very measured experimentation with caffeine prior to exercise. Start small–maybe just a cup of coffee, iced tea, or a soft drink before workouts–and then adjust the dose depending on the athlete’s response. However, individuals under 18 and those with high sensitivity to stimulants should avoid these products.

Selling Real Results

The sports nutrition section of my local grocery store contains dietary supplements with these claims on their labels:

• “Increase power output five-fold” • “Lose weight faster” • “Rapidly boost MUSCLE PUMP” • “Recover 10 times faster”

With enticements like those, who wouldn’t be tempted?

The bad news for athletes is that a promise on a supplement label doesn’t always mean much. But the good news, which is equally important to share, is that athletes can experience the benefits they seek from supplements through an approach anchored in sound sports nutrition.

As a sports dietitian, I have guided athletes to huge improvements in their performance, body composition, and overall health by changing their diet, hydration practices, and fueling habits before, during, and after exercise. In many cases, even small interventions have made a very big difference.

It’s vital to communicate that supplements, as their name implies, are intended to supplement diet and lifestyle factors–not provide a shortcut or “magic bullet.” Athletes need to understand that supplementation should always be secondary to nutritional strategies in helping them reach their goals.

If an athlete asks you about a caffeine-based supplement because they want more energy during practices and games, first find out if they’re eating enough carbohydrates in pre-activity meals. If they want to use an herbal product that promises to speed recovery, ask whether they’re eating appropriate meals after workouts to replace muscle glycogen stores. If they want to take a weight loss supplement, have them first keep a food diary for a week and evaluate whether they’re consuming too many empty calories or high-fat foods.

I receive many phone calls from high school-age athletes and their coaches and parents wanting to know which creatine supplement is best, how many cans of energy drink are safe, or how much protein powder per day is recommended. The fact is, the American Academy of Pediatrics (AAP) and the ACSM discourage the use of muscle-building supplements, protein supplements, and stimulants by individuals under 18.

However, I worry that responding with a flat “no” to these inquiries will only push athletes to other, less reliable sources of information. Instead, I talk about the athlete’s performance goals and about nutrition strategies that can provide a natural solution. I also explain why groups like the AAP and ACSM make their recommendations, and note that the science behind them far outweighs anything an athlete or parent will read on a supplement label.

The bottom line is that as long as athletes are driven to run faster, outmuscle their opponents, and go the extra mile–literally and figuratively–dietary supplements will appeal to them. Armed with the right information and evaluation strategies, you can help steer them clear of danger and toward a smart approach to sports nutrition that optimizes performance without introducing unwanted risks.

The author would like to thank Susan Kundrat, MS, RD, CSSD, (www.nutritiononthemove.net) for her contributions to this article.

Sidebar: Resources

Below are some excellent information sources that can help you evaluate dietary supplements.


This site includes information on specific dietary supplements and their individual ingredients. It also discusses physiological benefits, reported side effects, and potential drug/supplement interactions. Pharmacists regularly update the data. I personally use this resource often when evaluating dietary supplements. The subscription cost is under $100 per year.


The National Center for Drug Free Sport provides information, printable documents, and other resources aimed at educating athletes about how to use dietary supplements safely. Athletes and sports medicine professionals can anonymously call or e-mail staff members for information about supplement legality. Many services are free.


This resource conducts unbiased testing of various dietary supplements to evaluate purity and ensure that ingredient lists are accurate. I feel much more comfortable recommending a supplement that has passed a Consumerlab test. The cost is under $35 per year. dietary-supplements.info.nih.gov

This free resource from the National Institutes of Health’s Office of Dietary Supplements includes extensive supplement information, links to published studies, and product fact sheets.


The National Sanitation Federation provides programs through which companies can pay to submit their products for quality and purity testing. Dietary supplements with NSF approval are recognized as being pure and are more likely to be approved by sports governing bodies.


Informed-Choice is a not-for-profit partnership between supplement companies and HFL, a prominent anti-doping laboratory, created to help athletes, coaches, parents, and athletic trainers make sound choices about supplements. Informed-Choice has analyzed more samples for banned substances than any other lab in the world.

www.ncaa.org/health-safety — click on “Nutrition & Performance”

The NCAA’s Nutrition & Performance gateway page includes links to helpful information for athletic trainers, athletes, coaches, parents, and athletic administrators. Click on the “Student-Athlete” link for access to the association’s most up-to-date list of banned substances.

www.wada-ama.org — click on “Prohibited List”

The World Anti-Doping Agency was created by the International Olympic Committee (IOC) to combat drug use in sports, and maintains the IOC’s list of prohibited substances.

Shop see all »

75 Applewood Drive, Suite A
P.O. Box 128
Sparta, MI 49345
website development by deyo designs
Interested in receiving the print or digital edition of Training & Conditioning?

Subscribe Today »

Be sure to check out our sister sites: