To Supplement or Not to Supplement?

By Katherine A. Beals, PhD, RD, FACSM, CSSD and Breanne Nalder, MS, RD

“Faster,” “leaner,” “stronger,” “slimmer.” These are just some of the claims made by dietary supplements marketed to athletes. And, for athletes looking for that elusive competitive edge, these claims can be enticing. But, buyer beware. Most potential performance enhancing dietary supplements on the store shelves have not been rigorously tested for effectiveness or safety. Thus, athletes would be wise to exercise caution before purchasing a potential performance enhancing dietary supplement. This month’s nutrition column aims to assist the athlete in evaluating dietary supplements and determine which, if any, of the currently popular dietary supplements marketed to endurance athletes are worth the money.

Dietary Supplements: Who's Watching?

Dietary supplements are under the jurisdiction of the Food and Drug Administration (FDA); but, are regulated much differently than either foods or drugs. In fact, “regulation” may be too strong a term for the current governmental oversight of dietary supplements. This is largely due to the Dietary Supplement Health Education Act or DSHEA- a controversial piece of legislation that was introduced and ardently supported by Utah Senator Orrin Hatch back in the early 1990s. Under the protective umbrella of DSHEA, dietary supplement manufacturers are not required to prove that a supplement is effective before marketing it to the consumer. They also do not have to follow any particular manufacturing standards and they have an excessive amount of leeway with respect to the health claims they can put on a label, so long as they do not claim to actually treat a disease. Supplement manufacturers do have to file safety information with the FDA and must wait 75 days after filing to market the product. However, listing the information does not mean the FDA regards the product as necessarily safe. In practice, the FDA lacks the funds and the manpower needed to effectively police dietary supplements and/or remove them from the market, even if research suggests that they are “hazardous” to health. A good example of this is the case of ephedra (a stimulant that has been shown to cause severe negative health effects). Despite extensive research and numerous reports documenting the negative side effects of ephedra (and its alkaloids), the FDA was initially unable to remove the substance from the market, largely due to significant opposition from the supplement industry and the U.S. Congress. While it is currently banned, it is still fairly readily available for purchase on the internet and can be found in some products sold locally.

Fact or Fiction?

Given the insufficient regulation of dietary supplements by the government, it is really up to the athletes themselves to evaluate the safety and efficacy of supplements they are considering taking. The following questions can help guide that evaluation..

• Is the product marketed primarily by testimonials? This is a common marketing technique by supplement manufactures and should be regarded as highly suspect, especially when popular and/or famous athletes provide the testimonials. It is quite likely that the athlete pushing the product is being paid a pretty penny for his/her endorsement and has never even used the product or, at the very least is exaggerating the supposed results of the product.

• Are the claims provided by the supplement manufacturer backed by scientific research published in reputable, peer-reviewed journals? If not, it is very possible there is something about the research that the manufacturer doesn’t want the general public to know. Unpublished research claims are often based on research that has never been performed or on flawed research studies that are not supported by fellow scientists (i.e., peer-review). It should be noted that supplement manufacturers also often take published research out of context. So, even if there is research supporting a supposed benefit of the supplement, the athlete should carefully scrutinize the study for valid methodology and accurate interpretation of the results.

• Does the product use buzzwords and psuedo-medical jargon in their advertisements? Words such as “pumped”, “boost”, “ripped”, “balance”, “energize”, “detoxify”, etc. are popular among supplement manufactures because they sound good and can’t be objectively proven or disproved. (Indeed, how does someone measure balance? Would you know if you were detoxified?) Likewise if a product has a “secret formula” that is not known to the general scientific community be very skeptical!

• Does the product offer a quick fix or make claims that are just too good to be true? Remember, if it sounds too good to be true, it is! Improvements in athletic performance, changes in body weight and/or body composition, even recovery from intense training sessions take time and effort (and a well-balanced diet). No dietary supplement on the market today has been shown to make these processes easier or faster; thus, any supplement that claims to do so should be viewed with doubt.

To Supplement or Not to Supplement?

There is no doubt that athletes have unique nutritional requirements and need more of certain nutrients than their sedentary counterparts. However, these additional nutritional needs can generally met by a nutritious diet comprised of FOOD. With very few exceptions, most dietary supplements currently marketed to athletes are infective and some are downright dangerous. Instead of spending money on supplements to enhance athletic performance, the athlete would be better advised to contact a local sport dietitian for a dietary assessment and personalized food plan (see contact info below).

Popular Sports Supplements at-a-Glance

An exhaustive list of all the currently available dietary supplements marketed to athletes is beyond the scope of this article. However, below is a list of some of the most popular supplements used by cyclists, along with their claims, and the existing research supporting or refuting the claims.


Popular Sports Supplements at a Glance
Popular Sports Supplements at a Glance





Beta-Alanine: acts as a buffer in the muscle – Improves high-intensity exercise performance – Insufficient evidence to rate effectiveness

Branched-Chain Amino Acids (BCAA): leucine, isoleucine and valine – Delays fatigue

– Boosts the immune system – Does provide fuel for endurance activity; but has not been shown to delay fatigue as a result

– Growing research suggests they may play a role in supporting immune function

Caffeine/mild central nervous system stimulant – Enhances fat oxidation

– Aids in weight loss

– Delays fatigue – Some evidence that it does improve endurance performance.

– Some evidence that it aids in weight loss

– Some evidence that it increases mental sharpness; decreases perceived exertion

Carnitine/ transports long-chain fatty acids into the muscle mitochondrion for oxidation. – Enhances fat oxidation

– Aids in weight loss – No evidence that it enhances weight loss or improves athletic performance.

Chromium Picolinate/a mineral that plays a role in insulin function and glucose utilization – Enhances fat loss while preserving lean body mass

– No evidence that it enhances weight loss or positively impacts body composition.

Creatine Phosphate/ High energy compound used during high intensity, short duration exercise – Increase lean body mass

– Increase strength

– Improves exercise performance, especially for high-intensity workouts – Positive results have been found for increasing total body mass and lean mass

– Improves short-term intense exercise performance

– Increases strength gains with exercise

– Appears to be safe but not effective in some individuals (i.e., “non-responders”

Medium-Chain Triglycerides (MCT)/ Triglycerides consisting of fatty acids 6-12 carbons long. – Increase endurance

– Promote fat burning in long duration exercise – Does not enhance endurance performance

– May increase blood lipid levels; therefore not recommended

Pyruvate/ end product of glucose metabolism (i.e., glycolysis) – Increases endurance

– Decreases body fat

– Promotes weight loss – No evidence to suggest it enhances endurance performance

– Insufficient evidence for weight or fat loss

– Side effects may include adverse gastrointestinal effects, such as gas and nausea


*Source for charts and tables: Academy of Nutrition and Dietetics,

Katherine Beals, PhD, RD, FACSM, CSSD is an associate professor (clinical) in the Division of Nutrition at the University of Utah. She is a registered dietitian, a Certified Specialist in Sports Dietetics and a fellow of the American College of Sports Medicine.

Breanne Nalder, MS, RD recently completed here master’s degree in nutrition with an emphasis in sports dietetics at the University of Utah. She is a registered dietitian, certified ACE (American Council on Exercise) fitness instructor and races for DNA Cycling p/b Plan7 as a category 1 road cyclist. For personal nutrition coaching, you can reach Breanne at 801-550-0434 or [email protected]

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