top of page

Dietary supplements- are they safe?

If you have every taken a multivitamin, consumed a shake with protein powder, or added vitamin C powder to water then you have taken a dietary supplement. Dietary supplements include vitamins, minerals, herbals and botanicals, amino acids, enzymes and other products. Dietary supplements come in many forms including tablets, capsules, tinctures, powders, drinks, and energy bars.

Regulation of dietary supplements by the Food and Drug Administration is different than the regulation of food and drugs. Dietary supplements fall under the Dietary Supplement Health and Education Act of 1994. This means that the FDA does not ensure that dietary supplements are safe or effective before they reach the store shelves. This is the responsibility of the manufacturers and distributors of the supplements. The FDA states that manufacturers and distributors of dietary supplements are responsible for evaluating the safety and labeling of their products. The FDA can only take action against any adulterated or misbranded label after the product has reached the market. This usually occurs after an adverse event such as injury or death.

Supplements are usually presumed to be safe because people think they are “natural.” This assumption is not always true and in some cases dietary supplements can lead to injury or death. There was a case of a 22-year old Army private that died of cardiac arrest after using a dietary supplement called Jack3d. This supplement contained a substance that has similar effects on the body as the dangerous (and illegal) drug methamphetamine. There were many cases similar to this example and the FDA finally intervened and banned this product as well as many others that contained this same ingredient.

Liver damage has also been linked to several bodybuilding and weight loss supplements. There is a case of a teenager in Texas using a concentrated green tea extract he bought at a local nutrition store being sold as a fat burning supplement. After taking the supplement he was rushed to the emergency room after the whites of his eyes turned bright yellow. At the hospital he was told that he had severe liver damage caused by the use of the dietary supplement. This is not an isolated incident as research suggests that dietary supplements account for approximately 18% of drug-related liver injuries. When it comes to adulterated supplements the worst offenders tend to be those that promote weight loss, weight gain, and increased energy.

Dietary supplements are not all bad and in many cases they can be helpful. Supplements can be useful in reversing nutrient deficiencies and improving performance in athletes. The problem is that not all supplements are created equal. Many products hit the market before they have been sufficiently researched regarding their safety and efficacy. The dosage can also be a problem as many products may have an ingredient that has been researched to be both effective and safe, but the amount contained in the product is not disclosed. This often occurs with proprietary blends where it can be difficult to determine how much of each ingredient is contained in the product. Vitamin and mineral supplements are often the most overlooked because many people assume they are harmless, however, dosages well above the recommended daily allowance can cause toxicity. Certain dietary supplements can interact with medications by either enhancing or counteracting their effect. An example of this is vitamin K, as it can reduce the ability of the blood thinning medical Coumadin to prevent blood clotting. Before purchasing a supplement consider talking with a registered dietitian and do your own research from reliable and reputable sources.

Just because someone is trying to sell you a dietary supplement does not make them an expert. In some supplement stores the salesperson may work on commission so the more they sell the more money they make. Don’t assume the individual selling the supplement has a formal education in nutrition. They may have no background in nutrition or they may have only completed a weekend certification provided by the company they work for.

When deciding whether to take a supplement, take a look at your diet first. Work on building a solid foundation of health including good nutrition, sleeping the recommended 7-9 hours per night, and reducing stress. Supplements are not meant to replace a healthy diet or be a band aid for bad dietary or lifestyle choices. In fact the word supplement means “something that completes or enhances something else when added to it.” Keep in mind that the foods we eat contain many nutrients (vitamins, minerals, phytochemicals, carbohydrates, protein, fat, and antioxidants) that act symbiotically to promote health. You lose out on this symbiotic effect when you take an isolated nutrient in the form of a supplement. With this being said there are nutrients that certain people may need to supplement because it is difficult to get enough through diet. This is the case for vitamin D as dietary sources of this nutrient are limited. Individuals following a specific diet such as vegans or vegetarians may find it is difficult to get enough of certain nutrients through diet alone. In addition, certain athletes may need to supplement because of the elevated metabolic demands of their sport.

It is important to remember that there is no “one size fits all” approach to nutrition and dietary supplements. Just because it works for someone else does not mean it will work for you. If you have questions regarding dietary supplements it might be worth it to consult a registered dietitian to analyze and provide individualized recommendations regarding your current diet and help you decide what dietary supplement might be beneficial for you.


  1. National Institutes of Health Office of Dietary Supplements

  1. U.S. Food and Drug Administration

  1. United States Department of Agriculture- Dietary Supplements

  1. NSF Certified for Sport

  1. National Center for Drug Free Sport

22 views0 comments
bottom of page