April 2013 Issue

Ergogenic Aids — Competitive Edge or Hidden Danger?
By Constance Brown-Riggs, MSEd, RD, CDE, CDN
Today’s Dietitian
Vol. 15 No. 4 P. 24

Learn which supplements can safely boost endurance, enhance exercise recovery, and improve athletic performance—and which do not—to better counsel clients.

The pressure mounts as Joy Dubost, RD, PhD, CSSD, a master’s-level figure skater, competes to win a national championship. To win first place, she must glide effortlessly across the ice and maintain great posture, speed, endurance, strength, and height to perform triple toe loops and double axels with precision.

Before becoming a regular consumer of caffeine, Dubost, who’s board certified in sports dietetics and an experienced food scientist, says her skating wasn’t that great. Once she began including caffeine as part of her skating routine, she says there was a noticeable improvement. “Caffeine gave me a mental and physical boost,” she explains. “It made me feel more alert and energetic.”

Dubost trains for 90 minutes six days per week. One hour before each training session, she drinks 16 oz of caffeinated coffee. “That gives me about 100 mg of caffeine,” she says.

On the day of a skating event, Dubost maintains the same caffeine intake. “For me, it’s all about keeping the situation as close to what I’m used to as possible. I may even take a caffeine supplement to ensure I get the 100 mg.”

To repair muscle and boost glycogen stores, she drinks 1% chocolate milk after a hard skate instead of whey protein. “Rather than whey protein isolate, I get the benefit of all the essential nutrients found in milk,” she says.

As a dietitian who understands food science, Dubost clearly has an edge over her competition. But the majority of athletes don’t have that advantage. Most rely on hearsay as the gold standard for discerning whether an ergogenic aid is safe and effective. In fact, they’re often willing to try almost anything to produce that winning edge.

According to the International Society of Sports Nutrition, an ergogenic aid is any training or psychological technique, mechanical device, nutritional practice, or pharmacological agent that can help improve exercise performance capacity or enhance physical strength. These aids help prepare an individual to exercise, increase exercise efficiency, improve exercise recovery, and adapt to the rigors of intense training.

This article will evaluate the scientific evidence for and against some of the most common nutritional ergogenic aids that competitive athletes use.

Many athletes use caffeine as an ergogenic aid to boost performance and precipitate weight loss.1 Caffeine as an ergogenic aid has been well studied, and the consensus is that it is effective.2 Caffeine is a central nervous system stimulant that promotes a heightened sense of awareness and a decreased perception of effort.2

 “The strongest evidence for using caffeine as an ergogenic aid is in endurance athletes,” says Jennifer McDaniel, MS, RD, LD, CSSD, a specialist in sports dietetics and spokesperson for the Academy of Nutrition and Dietetics. Runners, cyclists, and cross-country skiers have been the primary subjects in these studies.

Research investigating the effects of caffeine on a timed trial with trained cyclists found that 5 mg of caffeine per kilogram of body weight improved speed, peak power, and mean power.1 Other studies have shown that swimmers and rowers who engage in high-intensity activities lasting one to 20 minutes can benefit from a more moderate dose of 2 to 3 mg of caffeine per kilogram of body weight.2

Roberta Anding, MS, RD, CSSD, CDE, LD, director of sports nutrition at Texas Children’s Hospital and sports dietitian for the Houston Texans’ NFL franchise and the Houston Astros baseball franchise, finds that caffeine makes her football players more alert with “quicker foot to the ball.”

Anding also refers to caffeine as a “first step enhancer.” She says small amounts of caffeine before a 100- to 400-m race can help the athlete with that first step.

Caffeine has been proven safe when taken in recommended doses. “The most recent evidence suggests that benefits from caffeine can be achieved by taking in 2 to 3 mg of caffeine per kilogram of body weight,” McDaniel says. This amounts to 100 mg of caffeine for a 110-lb athlete. “However, adverse effects such as rapid heart rate, dizziness, and feelings of hypoglycemia [eg, lightheadedness, jitteriness] have been observed when taken in larger quantities or for athletes who are caffeine sensitive,” she adds.

According to Heather Mangieri, RD, MS, CSSD, owner of Nutrition CheckUp, a Pittsburgh-based nutrition practice specializing in sports nutrition, and a dietitian working with adolescent athletes, cautions that caffeine doesn’t work the same for everyone. “Some athletes may find that it makes them jittery, anxious, or hyper. For others, caffeine can prompt bowel movements,” she says.

Studies report caffeine also may elevate blood pressure and heart rate.3 “So the day of a big competition is no time for an athlete to learn how caffeine will affect them,” Mangieri notes.

Bottom line: Caffeine is safe when taken in recommended doses and is an effective ergogenic aid to improve endurance and high-intensity activity lasting up to 20 minutes.

Carnitine is an amino acid synthesized by the body to help metabolize food into energy. It’s often marketed as a fat burner because it’s used in fat oxidation.4 Proponents claim supplemental carnitine will increase fat metabolism and enhance fat utilization, resulting in body fat loss.2 Carnitine is one of the most common nutrients found in weight-loss supplements.1

Despite decades of research, there’s a lack of evidence supporting carnitine as a fat burner or performance enhancer. In fact, more recent research is examining the effectiveness of carnitine supplementation in exercise recovery. Preliminary data indicate that carnitine supplements may help athletes endure intense training to a greater degree.1

It’s suggested athletes take 2 to 4 g of carnitine supplements daily, which is the dose used in most study protocols, and that’s considered safe.2

Although carnitine is safe at recommended doses, it’s not effective as an ergogenic aid.

Chromium Picolinate
Chromium is an essential mineral that enhances insulin sensitivity. Supplemental chromium usually is in the form of chromium picolinate. Picolinate facilitates greater gastrointestinal absorption.

Chromium picolinate has been marketed as an ergogenic aid with the promise of building muscle and promoting weight loss. Studies suggest chromium may enhance insulin’s actions. Since insulin promotes protein synthesis, chromium has been theorized to serve as an anabolic nutrient. “It’s also thought to enhance athletic performance and increase energy and vigor,” Mangieri says.

Initial studies in women have shown promising results. Study participants demonstrated an increase in muscle mass and strength during training. However, these results haven’t been duplicated, and the consensus is that chromium supplementation won’t change body composition in athletes either by increasing muscle mass or decreasing body fat.2

Evidence indicates chromium supplementation of 50 to 200 mcg/day seems to be safe.2 At higher doses, kidney failure and muscle wasting have been reported.3

While chromium is considered safe in recommended doses, there’s no reliable evidence that it will boost lean body mass or reduce body fat.

Creatine is an essential amino acid used in the body as a source of muscle energy. It’s one of the most widely used ergogenic aids and thought to be the most effective supplement available to increase high-intensity exercise capacity and muscle mass during training.1 More than 40% of the athletes in the NCAA reportedly use it.4

There’s a large body of evidence indicating that creatine supplementation can increase body and muscle mass during training. Studies show that athletes who have taken creatine have gained 2 to 5 lbs more than controls during four to 12 weeks of training.1 The gains were the result of creatine’s ergogenic effect as a performance enhancer during high-intensity exercise. Athletes who supplement with creatine can train harder, promoting greater physical strength and muscle growth.1

“There are some things that just flat out work,” Anding says. “If you’re working hard in the weight room, training really hard … just when you don’t think you can do one more rep, creatine can help with that edge” to complete the repetition.

In the past, experts debated the safety of creatine supplementation, but recent studies on its long-term safety report no side effects when it’s taken in recommended doses. Creatine also has the potential to lessen injury during training.1

Athletes usually supplement with 3 to 5 g/day. However, when taken in larger doses, creatine can cause gastrointestinal disturbance and cramps.2
At recommended doses, creatine is a safe and effective ergogenic aid that can increase muscle growth, strength, and power.

Conjugated Linoleic Acid
Conjugated linoleic acid (CLA) is a group of chemicals found in the essential fatty acid linoleic acid. Research shows that when CLA is added to animal feed, it decreases body fat and increases muscle and bone mass in animals. As a result of these findings, supplementation with CLA has been recommended to athletes to help manage body composition and delay bone loss.1 However, study results in humans have been inconsistent, and there’s little evidence that CLA supplementation will promote weight loss or directly impact performance.2

More research is needed to determine an appropriate dose for humans. Moreover, the safety of CLA in humans hasn’t been established, and conclusions about its effectiveness as a weight loss aid for humans is mixed.

Branched-Chain Amino Acids
Branched chain refers to the chemical structure of the essential amino acids leucine, isoleucine, and valine. Athletes use branched-chain amino acids (BCAAs) to improve strength, power, and endurance. BCAAs started receiving more attention as an ergogenic aid when researchers discovered that after three hours of exercise, BCAA levels in the blood dropped dramatically, and the enzyme keto acid dehydrogenase, which is responsible for the breakdown, increased.

Researchers theorize that BCAAs provide energy to active muscles because keto acid dehydrogenase is most active when carbohydrate stores are low.3 Moreover, decreasing levels of BCAAs in the blood have been linked to central nervous system fatigue, which leads to decreased sport performance.3 Thus supplementation with BCAAs may prevent reduced levels in the blood and potentially prove beneficial during prolonged endurance exercise. However, studies in endurance athletes who supplemented with BCAAs haven’t been able to yield consistent results.1

Nevertheless, taking 5 to 20 g of supplemental BCAAs per day in divided doses seems to be safe.2 However, they’re not proven effective for improving performance.

Whey Protein
Protein supplements often are advertised as an effective way to build muscle and increase strength. Whey protein always has been a popular choice because of its high biological value—equivalent to egg protein.2 Studies show that whey protein supplements boost muscle mass and are superior to casein and soy protein. In studies comparing whey protein with casein or soy protein, whey supplementation led to greater increases in lean mass, larger decreases in fat mass, and better improvements in strength.2

Whey protein seems to be safe for healthy athletes who don’t have latent or known kidney or liver disease.2 However, intakes exceeding 2.5 g/kg of body weight put athletes at risk of dehydration, low carbohydrate intake, excessive energy intake, and increased excretion of urinary calcium.2

It’s common for sports nutrition professionals to recommend protein supplementation to some athletes to meet dietary requirements. Protein supplementation provides essential amino acids to optimize protein synthesis after exercise.1

Androstenedione, also called Andro, gained popularity in 1998 when professional baseball player Mark McGwire admitted using it during his record-setting home run season.2 Since then, androstenedione has become popular among body builders who believe it’s a natural booster of anabolic hormones, resulting in increased muscle mass and strength.1,2

Androstenedione is a prohormone that the body can potentially convert to testosterone. Some data indicate that prohormones increase testosterone levels; however, there’s scant evidence that prohormones boost muscle mass in young men with normal hormone levels.1 In fact, most studies indicate androstenedione is dangerous, and that it doesn’t affect testosterone levels. Study findings show it may increase estrogen levels and reduce HDL cholesterol, and is associated with at least 25 other life-threatening side effects,2 such as “an increased risk of breast, pancreatic, and prostate cancer,” Mangieri says. In addition, there are safety concerns that the potency and purity of androstenedione products vary significantly.

These safety issues prompted Congress in 2004 to pass the Anabolic Steroid Control Act, listing androstenedione as a controlled substance that can’t be sold without a prescription. For this reason, most sports-governing bodies list androstenedione as a banned substance. Also, it’s not deemed safe or effective as an ergogenic aid.

Known as DHEA, dehydroepiandrosterone is another popular prohormone among athletes that’s often promoted as a fountain of youth.2 It’s said to increase testosterone levels, resulting in increased muscle mass and metabolic rate.

DHEA is considered a weak prohormone with no evidence of its ability to boost muscle mass or enhance athletic performance. Although androstenedione is banned under the Anabolic Steroid Control Act, athletes can purchase DHEA over the counter. Its safety profile is unknown since studies have yet to determine the effects of high doses or long-term use.2

At this time, DHEA supplementation isn’t recommended for athletes.

Educating Athletes
It’s important for RDs to understand that supplement use is widespread among athletes of all ages and at every level. Aspiring athletes as young as those in middle school are using supplements.2 Adolescents often feel pressure to obtain athletic scholarships and look to ergogenic aids as a way to realize their goals. That’s problematic because RDs don’t have evidence supporting the use of nutritional ergogenic aids in young athletes. “Most of the research we have on ergogenic aids is done on the adult population over the age of 18,” Mangieri says.

Elite athletes know that competitions are won or lost by slim margins, and many feel an ergogenic aid may be the silver bullet they need to win. Other athletes feel pressured to use nutritional ergogenics to maintain a competitive advantage over their peers who are already using supplements.

If athletes ask about a specific ergogenic aid, RDs should provide as much unbiased information as possible. Dietitians should tell athletes what’s known and unknown about the product based on current scientific evidence, including potential side effects and safety issues.

RDs should help athletes understand that nutritional ergogenics may contain banned substances, which could lead to disqualification in their sport even if they were unaware that the supplement was contaminated. Anding tells athletes that “you and you alone are responsible for what goes in your body,” and because ergogenic aids are unregulated, they may contain banned substances not disclosed on the product label.

If RDs can guide athletes away from disproven and dangerous supplements while maintaining open and honest lines of communication, then more serious health risks can be prevented. The following tips from the pros can help dietitians better counsel athletic clients:

Develop competency. RDs who desire to work with competitive athletes need continuing education to stay abreast of the constantly changing and challenging aspects of nutritional ergogenics. Sports nutrition is popular, and many new dietitians are entering the sports nutrition field.

“This is a sexy dietetic specialty,” Anding says. “Athletes need sports dietitians to help them navigate these waters, but it takes years of experience and education to develop the competency to take care of highly competitive athletes.”

Know the science. “Athletes are more knowledgeable than the average consumer; they take it [supplementation] very seriously and believe it will give them a performance edge,” Dubost says. RDs should look at the total evidence, not just one or two supplements. Knowing the science is extremely important because athletes will come in well versed.

Build trust. “Keep an open mind about ergogenic aids,” Mangieri says. “If an athlete believes the dietitian is [against] supplements, they may not disclose that they’re taking them. Dismissing ergogenic aids immediately breaks trust with clients, and we miss an opportunity to educate [them about] an important topic.”

Athletic careers have been sidelined as a result of supplementation with products that are on the National Commission for Certifying Agency’s banned substance list. Mangieri believes discussing this list is a great way to broach the subject of ergogenic aids.

Address immune function. “We forget that athletes are immune compromised because of the stress of training. They need education on the proper diet and supplementation to support good immune function,” says Dubost, whose biggest fear is not feeling well on the day of her skating competition. To ensure she maintains her competitive edge, she includes an immune supplement in her daily routine.

— Constance Brown-Riggs, MSEd, RD, CDE, CDN, is the national spokesperson for the Academy of Nutrition and Dietetics, specializing in African American nutrition, and author of the African American Guide to Living Well With Diabetes and Eating Soulfully and Healthfully With Diabetes.


Evaluating Ergogenic Aids
Asking the following questions and using these resources can serve as a guide to help nutrition professionals evaluate ergogenic aids and provide accurate information to clients.

Is the Supplement Safe?
• Check the FDA’s website (www.fda.gov) for drug recalls, withdrawals, and safety alerts, and follow the FDA on Twitter @FDArecalls for timely information.

• Visit the Public Health and Safety Company website (www.nsf.org) for a list of substances that have been certified or banned in sports.

Is the Supplement Effective?
Determine whether the claims made are physiologically plausible by reviewing the scientific literature:

• Search reputable free databases such as PubMed (www.ncbi.nim.nih.gov/PubMed).

• Search member-only databases such as the Academy of Nutrition and Dietetics’ Evidence Analysis Library (www.adaevidencelibrary.com), the Natural Medicine Comprehensive Database (www.naturaldatabase.com), and EBSCO (www.ebscohost.com).

• Read review articles about a specific supplement.

• Search websites with evidence-based supplement information, such as SupplementWatch.com.

Is the Supplement Free From Contamination?
Visit the following websites to help answer this question:

ConsumerLab.com (search for athletic banned substances screened products);

• US Pharmacopeia (www.usp.org/USPVerified); and


— Information adapted from reference 2


1. Kreider RB, Wilborn CE, Taylor L, et al. ISSN exercise & sport nutrition review: research & recommendations. J Int Soc Sports Nutr. 2010;7:1-43.

2. Dunford M, Coleman EJ. Ergogenic aids, dietary supplements, and exercise. In: Rosenbloom CA, Coleman EJ, eds. Sports Nutrition: A Practice Manual for Professionals. 5th ed. Chicago, IL: Academy of Nutrition and Dietetics; 2012:128.

3. Fink HH, Burgoon LA, Mikesky AE. Practical Applications in Sports Nutrition. 2nd ed. Sudbury, MA: Jones and Bartlett; 2009:234-279.

4. Sizer FS, Whitney E. Nutrition Concepts and Controversies. 12th ed. Belmont, CA: Brooks Cole; 2011:400-406.