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  1. Define a dietary supplement and what substances are considered dietary supplements.

  2. Explain the limitations of dietary supplement regulation in the United States.

  3. Describe the product claims, efficacy, and safety of popular, commonly used dietary supplements for weight loss, health, and performance.

  4. List the potential harmful effects associated with key dietary supplements.

  5. Define the scope of practice for health professionals with regard to the recommendation and sale of dietary supplements.


Visit DavisPlus at for study and practice resources, including online quizzes, animations that help explain physiological processes, podcasts concerning news and career trends in exercise physiology, and practice references.



  • Anne Marie is a 37-year-old advertising executive who is very motivated to continue improving her overall fitness. During the time Anne Marie has worked with her personal trainer (more than one year), she has exceeded her initial fitness goals. Outside of an existing diagnosis of mild hypertension, she is otherwise very healthy but wants to accomplish more-push herself harder, lose weight, and get stronger. In an effort to continue her progress, she asks her personal trainer for advice on nutritional supplements. Given Anne Marie's desire to boost her fitness and performance, her personal trainer suggests a combination of different supplements that he believes will help her achieve her goals. They include:

    • Thermadrene, a thermogenic stimulant containing ephedrine

    • Yohimbe, an extract of a tree bark that is thought to increase athletic performance

    • Whey protein to improve muscle strength

    • Essential fatty acids (Omega-3 fatty acids) that can benefit heart health

    • Lean-mass enhancement shakes (high-protein meal replacement) consumed twice a day

    Anne Marie decides to purchase each of the recommended supplements and begins using them as a complement to her training program.

    As a health/fitness professional, do you see any potential concerns regarding the actions of the trainer, that is, when he makes supplement recommendations to his client?

    • After taking the recommended supplements for about 3 months, Anne Marie collapses during an early-morning workout. She is rushed to the hospital, but by late evening she is pronounced dead from a massive brain hemorrhage. After investigation, the ephedra-containing Thermadrene is believed to be the most likely culprit. The Chinese botanical ma huang, also known as ephedra, reduces appetite, but also is associated with significant life-threatening adverse effects, including dangerously increased blood pressure, heart attacks, seizure, stroke, and serious psychiatric illness.13 Anne Marie's pre-existing hypertension combined with physical exertion and ephedra use presumably predisposed her to the massive brain hemorrhage that ultimately took her life.14

    • The story of Anne Marie's death played out in the media in the case of Capati v Crunch Fitness, in which Anne Marie's personal trainer and fitness center were sued for $320 million. Ultimately, the case was settled before going to trial, with the gym and the trainer liable for $1,750,000.


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