Review of the dietary supplement landscape

November 1, 2023 - By Rachel Kubik, Senior Content Writer for ARC

Fish oil. Multivitamins. Probiotics. Vitamin C. B-12. According to the American Pharmacists Association, 77% of Americans take at least one dietary supplement on a regular basis. A dietary supplement is an ingestible product containing “dietary ingredients” designed to complement the diet, including vitamins, minerals, herbs and amino acids, according to the Food and Drug Administration. These supplements can take various forms, such as pills, tablets, capsules, gummies, softgels, liquids and powders, and they are labeled as dietary supplements. 

These supplements address a broad spectrum of health-related concerns, from vitamin and mineral deficiencies to enhancing overall well-being and targeting specific health conditions. However, while these supplements can offer potential benefits, their usage should be approached with care, considering individual health needs and any potential interactions with medications. Given the varied and sometimes complex nature of dietary supplements, health and wellness professionals can provide valuable insights to assist consumers in making informed decisions about their use. 

The dietary supplement category does not include products approved as new drugs, licensed as biologics or authorized for clinical investigation unless they were previously marketed as supplements or food. Popular supplements include vitamins D and B12; minerals like calcium and iron; herbs such as echinacea and garlic; and products like glucosamine, probiotics and fish oils, according to the U.S. Department of Health & Human Services’ National Institutes of Health. 

Under the Dietary Supplement Health and Education Act (DSHEA) of 1994, the FDA cannot pre-approve dietary supplements for safety and efficacy before they are sold. In fact, in many instances, companies can legally introduce dietary supplements to the market without prior notification to the FDA. Since DSHEA’s implementation, the dietary supplement market has expanded considerably, with the number of products increasing almost 20 times since 1994. Dietary supplements play a role in many Americans’ overall health. 

The FDA does not routinely analyze the content of dietary supplements. Due to limited resources, the FDA prioritizes its efforts on public health emergencies, products linked to injuries or illnesses and those suspected of being adulterated or fraudulent. The remaining resources are dedicated to analyzing samples collected during manufacturing firm inspections or as part of routine marketplace monitoring. The FDA does not conduct testing on dietary supplements before they are made available to consumers. For product content analysis, consumers may contact the dietary supplement manufacturer or commercial laboratories. If a product sold as a dietary supplement is explicitly or implicitly promoted as a treatment, prevention or cure for a specific disease, it is considered a drug and subject to regulation as such, according to the FDA. Certain supplements may interact with medications or other supplements, potentially impacting health, and consumers are always encouraged to consult with their doctor. 
 

The supplement landscape  

While some dietary supplements can provide essential nutrients for individuals who don’t eat a varied nutritious diet, they can’t replace the diversity of foods needed for a healthy diet. Key sources for understanding healthy eating routines are the Dietary Guidelines for Americans and USDA’s MyPlate. Certain dietary supplements can enhance overall health and manage some specific conditions. For example, calcium and vitamin D support bone health, folic acid reduces the risk of birth defects, omega-3 fatty acids from fish oils can benefit those with heart disease, and a combination of vitamins C and E, zinc, copper, lutein and zeaxanthin may slow vision loss in age-related macular degeneration.  

Weight-loss supplements with ingredients such as caffeine, calcium, green tea and green tea extract, are often marketed as aiding weight reduction by blocking fat or carb absorption, curbing appetite or accelerating metabolism. These supplements are not extensively studied in larger groups over extended periods, according to the NHI. Weight-loss supplements are an option to consider, along with other lifestyle changes like a healthy diet, calorie reduction and exercise, under healthcare provider guidance. 

Apple cider vinegar, made from fermented apple juice, is commonly used in food but has gained popularity as a dietary supplement, with claims of various health benefits such as appetite suppression, weight loss, digestive health and immune support. Limited scientific evidence supports these claims, with some research suggesting potential benefits, especially related to blood sugar, insulin, cholesterol and weight loss, though the evidence quality is low and studies are small, according to the Department of Defense Dietary Supplement Program. 

A collection of resources from the USDA addresses dietary supplements for athletes and their impact on performance. It covers various supplements, including anabolic steroids, caffeine, creatine, ephedra and whey protein, providing information on what they are, their use among athletes, safety concerns and potential interactions.   

Lastly, essential oils are commonly used for their pleasant scents and are sometimes marketed as potential dietary supplements.  The concentration and safety of essential oils may not always be clear, according to the Department of Defense Dietary Supplement Program. It is helpful for all dietitians and health and wellness professionals to know the entirety of the supplement landscape when interacting with consumers.  

Safety and risk 

Media coverage of dietary supplements has included select warnings around safety and risk when used in high doses, as substitutes for prescribed medications, or in conjunction with multiple supplements. Some supplements may increase the risk of bleeding, change responses to anesthesia or interact with medications. For example, vitamin K can affect the blood-thinning medication warfarin, while St. John’s wort (hypericum perforatum) can impact various drugs, including some antidepressants and birth control pills. Antioxidant supplements like vitamins C and E may interfere with certain cancer chemotherapy. It’s worth noting that some foods, such as breakfast cereals and beverages, may contain added vitamins, minerals and other supplement ingredients, so consuming more than necessary must be monitored. Extra vitamin A, for instance, can lead to headaches, liver damage, weakened bones and birth defects, while excess iron can result in nausea, vomiting and organ damage.  

Education

The FDA in partnership with the American Medical Association has an educational program aimed at helping healthcare professionals, particularly physicians, in comprehending the regulation of dietary supplements and disseminating information about their advantages and risks to patients. These videos cover topics like regulation, labeling, claims, risks, interactions, laboratory test interference and hidden drug ingredients associated with dietary supplements. They also address how to report adverse events linked to supplement use and offer guidance for healthcare professionals when discussing dietary supplements with patients.