Take care: Dietary supplements can be bad for your health
A study conducted in 2017-18 by the U.S. Centers for Disease Control and Prevention showed that 57.6% of adults had used a dietary supplement within the last 30 days. Adults aged 20 or older used one (22.5%), two (13.8%), three (7.5%) or more (13.8%) dietary supplements over the past month.
Although the supplements most often consumed were common vitamins and minerals, many supplements contained herbs, other botanicals, amino acids and numerous other substances.
Many people assume supplements are safe, but that is not always the case. In 2024 alone, there were 11 recalls for supplements, one because of contamination with salmonella and another because of contamination with toxic yellow oleander. The remaining nine contained undeclared pharmaceutical drugs or contained two or more pharmaceutical medications. These undeclared drugs included prescription-strength, nonsteroidal anti-inflammatories, corticosteroids, erectile dysfunction drugs, antihistamines and other substances. Many also contained acetaminophen.
A study published in The New England Journal of Medicine in 2015 estimated that 23,005 emergency department visits were attributed to the patient’s use of dietary supplements. According to a research article published in 2018 in The Journal of the American Medical Association, “serious adverse events reported with the use of dietary supplements include stroke, acute liver injury, kidney failure, pulmonary embolisms, and death.” The consumption of pharmaceuticals without a prescription can result in drug interactions or other risks.
For example, sildenafil can be used to treat pulmonary arterial hypertension, but taking the medication while taking nitrate prescription drugs or other medicines for hypertension can result in a sudden decrease in blood pressure. Supplements that contain the undeclared medication, sibutramine, a weight-loss medication that was discontinued in the U.S. in 2010, can cause heart attack or stroke, which may result in death.
Of further concern, a study published in JAMA in 2023 showed that 89% of supplements did not accurately declare the ingredients in the product, with 40% not containing a detectable amount of the ingredient listed on the label. For products that correctly listed ingredients, the ingredient quantity ranged from 0.02% to 334% of the labeled amount. Of the products tested, 12% contained ingredients prohibited by the U.S. Food and Drug Administration.
The manufacturers of supplements are required to notify the FDA before marketing and selling the supplements and provide a rationale for the safety of the ingredients. Although the FDA oversees dietary supplements, the regulatory process differs significantly from that of prescription drugs and food and the FDA is not “authorized to approve dietary supplements for safety and effectiveness before they are marketed.” Although the FDA can take action against a manufacturer selling unsafe or improperly labeled products, reporting of adverse events by consumers or health care professionals is voluntary, so the FDA is not often made aware of these adverse events. Additionally, the rapid growth of the dietary supplement market has proved challenging for the FDA to respond given their resources. The FDA states they allocate resources toward public health emergencies and products that may have caused illness before focusing on products suspected to be adulterated, fraudulent, or unlawful.
So, how can you know which supplements are safe to use? First, the FDA recommends talking to your doctor before using a dietary supplement to ensure it will not interact negatively with current medications or worsen an existing condition, and be sure to report any supplements you are taking to your doctor.
Always be wary of claims that the supplement can cure a disease or is a scientific breakthrough. Only buy supplements from reputable companies, never from unknown companies selling products online or in magazines. Many pharmaceutical companies also make nutritional supplements and may be more likely to follow regulations and good manufacturing practices. Supplements containing seals from the United States Pharmacopeia or the National Sanitation Foundation have undergone additional testing and meet strict testing and evaluation criteria to ensure quality standards and thus are usually a safer choice.
More information about supplements is available at the FDA’s Information for Consumers on Using Dietary Supplements website at bit.ly/4ib2nLU.
Smith is an associate professor and statewide consumer food specialist for Washington State University in Pullman. Comments or questions may be emailed to food.safety@wsu.edu.
