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Dietary Supplements: The Good, The Bad and The Ugly

benefits of dietary supplements

Dietary Supplements: The Good, The Bad and The Ugly

The multibillion-dollar world of dietary supplements is confusing.  With over 29,000 supplements available, that should come as no surprise. 

Where do you turn? 

Who can you trust? 

And are these products all they promise?

Worldwide annual sales in the “sports and fitness nutrition” arena are worth an estimated $25+ billion dollars.  With projected growth at 7% per year, there seems to be no slowing in this market, with Latin America leading the charge in the marketplace.  Is all the money being spent worthwhile?

“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.” Bob Murray, Ph.D., FACSM, Founder of Sports Science  Insights, LLC

While often times clever marketing promises that supplements are “magic bullets,” most of these claims lack scientific merit.  Yet in the often murky supplement waters, the proverbial “golden egg” can appear.  It’s these golden eggs that athletes yearn for to make them bigger.  Make them stronger.  Make them faster.  Or maybe it’s your mother, grandfather, or elderly Great Aunt who is simply trying to slow the aging process and do all they can to stay as youthful — physically and mentally — as possible.

You can find nutritional supplements in every pharmacy, grocery store, and vitamin shop. Internet websites offer additional opportunities for all kinds of supplements (legal and otherwise) to be easily obtained by just about anyone. While easy access leads consumers to believe that all supplements are safe and effective, it is always important to understand what is going into your body.  The stakes are even higher for athletes who are in danger of testing positive for illegal and banned substances.

Imagine an athlete, taking a product he or she thinks is safe and will benefit their performance, then they test positive for a banned substance.  It’s happened.  More than once.  And it has ruined careers.

Of course, this isn’t pointing fingers; many supplement manufacturers and companies are honest and ensure their products include only the ingredients on the label in the amounts on the label.  It’s, unfortunately, the “others” that make all the noise, get all the attention and give the industry a very bad wrap.

So how can supplement manufacturers get away with this?  What can you do to seek out safe products? 

Here are some resources for finding trusted products that ensure quality is there and they are meeting label claims.

United States Pharmacopeia (USP)

This is a nonprofit “standards-setting group” that tests and evaluates dietary supplements as well as prescription and over-the-counter medicines.  USP conducts independent research and testing to verify the quality, potency, and purity of dietary supplement ingredients.  The USP symbol is one-way consumers can find out if their product can be “trusted” —  while it means nothing about the effectiveness of the product, the USP verifies the quality, purity, and potency of dietary supplement finished products.  Only those that meet USP’s stringent criteria can use the USP Verified Dietary Supplement Mark on their product labels.

Further, consumers can also visit the USP website to search for verified products by brand name and information on where to buy them.

USP is a trusted resource for the average consumer.  However, athletes need to be assured that if they are taking dietary supplements, the products are free from any and all banned substances.

Two organizations now offer “testing” so athletes can put the trust in their products so they know if it’s on the label, it’s in the product … and, conversely, if it’s NOT on the label, it’s NOT in the product. 

NSF Certified for Sport™

This Organization has developed an athletic banned substances certification program. They conduct testing on supplements and certify that they are free of banned substances and contain the quality and quantity of ingredients listed on supplement labels. All information is available on their free online database.

Informed Choice

Similar to NSF, Informed-Choice is a quality assurance program designed to evaluate and certify sports nutrition products. They also offer an online search engine to determine if products are listed.

“The only objective evidence of high quality is third-party testing. Anybody can claim that a supplement is a high quality and pure, but only third-party, independent testing can prove it. Any reputable company should be able to provide third-party test results to substantiate their claims.” – Joar Opheim, Nordic Naturals CEO

It’s important to understand the importance of this for athletes and non athletes alike.  Without “sounding the alarms” — there have been several studies now showing that It is not uncommon for supplements to include ingredients that are not listed on their labels. In some cases, these ingredients are illegal or banned substances.

In 2004 The International Olympic Committee (IOC) published reports that nearly 15% of 634 supplements tested contained illegal or banned substances not listed on the labels.  A similar report from the HFL Sport Science Institute in 2007 found that 25% of 52 supplements tested (all were available for purchase in the US) contained small amounts of steroids and other banned stimulants.

The Regulation of Dietary Supplements

Dietary Supplement and Healthy Education Act (DSHEA)

Supplements are treated very differently by the government than foods and drugs. In response to the growing popularity of supplements and years of flip-flopping over which government agency should police dietary supplements, the Dietary Supplement and Healthy Education Act was passed in 1994.  

The act holds the manufacturer of the supplement responsible for ensuring its safety before it is marketed. Therefore these products do not need FDA registration or approval prior to their sale. Manufacturers are also responsible for ensuring that the information on labels is “truthful and not misleading.”

The FDA is then responsible for monitoring safety, assessing voluntary reports of adverse effects, labeling claims, and packaging literature. They can step in and take action against unsafe supplements after they have reached the market, but only after they have shown the product is unsafe. This system makes things more difficult to regulate since government intervention can occur only after products have been released to the marketplace.

The Risks

Without proper education, supplement use can be incredibly dangerous. Ingestion of supplemental forms of many vitamins, minerals, herbs, and other substances can result in dangerous side effects, allergic reactions and interactions with medications.

Since there is a lack of enforcement of the regulations in place, many supplement manufacturers do not spend the money required to do extensive research on the safety and effectiveness of their products. Some less reputable companies use the lack of regulation to cut corners and sell substandard ingredients.

A warning from the FDA website reads:

“Some of the products claim to be “natural” or only contain “herbal” ingredients, but actually contain potentially harmful ingredients not listed on the product’s label or in promotional advertisements.  These products have not been approved by the FDA, are illegal, and may be potentially harmful to unsuspecting consumers.”

The question then becomes, how DO you evaluate dietary supplements?

In order to evaluate a product effectively, health professionals must do extensive research including:

  • Carefully read nutrition facts and ingredient labels on all products
  • Review current scientific literature available on the nutrients in the supplement

Search for information using PubMed or another reputable database with scientific studies

Refer to reliable peer-reviewed journal articles

  • Check the FDA website for consumer advisories and recalls
  • Review annually updated banned substance lists available from the NCAA, IOC and World Anti-Doping Agency (websites below)
  • Seek advice from a registered dietitian with experience with sports nutrition

Take Away Tips

  1. Make safety the number one priority.
  2. Evaluate safety and effectiveness using reliable sources.
  3. Do your homework before recommending dietary supplements. Confirm quality with any of the sites listed above.  More specifically, if working with athletes, it is always best to look to brands and products that have been verified as NSF or Informed Choice to ensure they are free from banned substances.
  4. Avoid banned and illegal substances. 

When there is a need for supplementation

The main vitamins and minerals of concern in the athlete’s diet are calcium, vitamin D, B-vitamins, iron, zinc and some of the major antioxidants (vitamins C, E, beta-carotene, and selenium). Athletes most at risk for deficiencies are ones who restrict calories or participate in dangerous and drastic weight loss practices.

Sometimes supplements are necessary. Though nutrients are almost always absorbed better from food, there may be a need for additional supplementation. Examples of supplements that can be beneficial when taken properly are a basic multivitamin, calcium, and iron. Safe versions of these supplements are typically available all over the country.


Simple is better when it comes to multivitamins. An extra dose of vitamin and minerals may be necessary for an athlete with a limited diet. Multivitamins should not be considered a replacement for fresh foods or an “insurance policy” for a limited diet, but they can help give athletes adequate amounts of many of the nutrients they may be missing.

When choosing a multivitamin, pay close attention to the ingredients. Look for a combination of vitamins and minerals and check that there are no herbs or other substances in the product.

More is not better, choose multivitamins that contain mostly 100% or less of the percent daily value (%DV) if possible. Steer clear of those with 5,000% and 10,000% of the % Daily Value. To avoid stomach upset and maximize absorption, take a multivitamin on a full stomach.


Calcium intake tends to decrease with age, especially for females (see Figure 13.1). Since calcium is vital to bone strength, growth, and development, an extra supplement may be necessary.  When choosing a calcium supplement, look for one that comes in dosages of 500mg or less because the body can not absorb more than 500 mg at a time. It may be necessary to take up to 1000-1500 mg of supplemental calcium a day which means that it may need to be taken at two different times. Multivitamins typically do not contain enough calcium so a good strategy is to take one dose of calcium with a multivitamin in the morning and the second dose at night. There are a variety of options for calcium supplementation including chewable antacids, chocolate or fruit-flavored chews, as well as calcium-fortified cereals and juices.


Female or vegetarian athletes, especially those that participate in endurance sports, may benefit from iron supplementation for treatment of iron deficiency. An iron deficiency must be diagnosed with a blood test prior to supplementation because too much can be toxic to the liver.  Iron absorption is enhanced by vitamin C. If an iron supplement is prescribed, take it with foods and beverages that are high in vitamin C.

Learn more in the Fitness Nutrition Coach program, and the Sports Nutrition Specialist program.