The Dietary Supplement Health and Education Act (DSHEA) of 1994 classified dietary supplements as food. As such, they are not required to obtain FDA approval before being introduced to the market, but the Act did provide the FDA with the ability to remove any product it deems unsafe from the market. Additionally, it established marketing guidelines that prevented supplements from making claims that they can treat, prevent, mitigate, cure, or diagnose diseases.
Despite the lack of FDA oversight, millions of patients use readily available dietary supplements that do not require a consultation with a medical professional to obtain. It is estimated that three in five adults use a dietary supplement. However, many patients do not mention these to their doctors, further raising safety concerns. This requires physicians and healthcare professionals to remain vigilant and up to date on the various aspects of dietary supplements.
Related: An Overview of Dietary Supplements
Safety and efficacy of dietary supplements
The Food and Drug Administration (FDA) does not mandate that dietary supplement manufacturers provide evidence of efficacy. However, the manufacturers wishing to include a new dietary ingredient must notify the FDA that the supplement is expected to be reasonably safe before it is allowed to be marketed. If the FDA has concerns, it can request additional information from the manufacturers to support its safety claim.
Post-market surveillance is then used to confirm the safety of dietary supplements on the market. The FDA mandates that manufacturers and distributors report any serious adverse events through the MedWatch system within 15 days.
Many patients believe dietary supplements are beneficial for their general health or can help treat or prevent specific health conditions and are safe for consumption. This belief often comes from the natural origins of the ingredients—derived from plants or animals—and the purported centuries of use in non-traditional medicine. However, this has oftentimes not been verified by scientific studies.
The number of research studies evaluating dietary ingredients continues to increase, but there are still significant gaps in our understanding of many dietary supplements. For a quick overview of various natural ingredients, information is available through the National Institutes of Health’s National Center for Complementary and Integrative Health (NCCIH).
Purity and accuracy
The lack of stringent regulation and oversight in the supplement industry raises concerns regarding the actual content of these products. Supplements may not always contain the ingredients or the quantities indicated by the manufacturer.
There is also a risk that products might include unlisted components. These can range from inert substances to potentially harmful elements, such as natural toxins, pesticides, heavy metals, or unapproved colorants. Additionally, consumers may encounter variability in the amounts of active ingredients present, particularly in herbal products that consist of complex mixtures.
This inconsistency poses challenges for conducting robust clinical trials and making comparisons across different studies. To combat this, regulations governing supplement production in the United States introduced Good Manufacturing Practices (GMPs). GMPs enhance standards for maintaining cleanliness in manufacturing facilities and ensuring the purity and integrity of raw materials. These guidelines also help ensure the proper labeling, packaging, and storage of the final products.
Additionally, the U.S. Pharmacopeial Convention (USP) provides a verified mark for consumers that the product contains the ingredients on the label in the declared potency amounts, does not contain harmful contaminants, and complies with FDA GMPs.
Categories of dietary supplements
The number of dietary supplements available to consumers continues to grow. This makes it difficult for physicians and healthcare providers to remain up to date on the benefits and risks of each supplement. However, each ingredient can be broken down into one of four main categories: vitamins, minerals, herbs, and botanicals.
Vitamins
Vitamins are essential organic compounds required in small quantities for normal health and growth. Unlike other critical biological substances, such as proteins, carbohydrates, and lipids, which can generally be synthesized in sufficient amounts, vitamins must be obtained through dietary sources or synthetic means. This earns them the designation of essential nutrients.
These compounds play crucial roles in facilitating or regulating vital chemical reactions within cells. A lack of any vitamin in the diet, or improper absorption by the body, can lead to specific deficiency diseases.
Vitamins are further classified into two categories: water-soluble and fat-soluble vitamins. Each category displays a unique absorption and elimination profile and can produce varying effects on the body.
Minerals
Minerals, like vitamins, are key nutrients necessary for a variety of bodily functions. The primary distinction between the two is that vitamins are organic substances—containing carbon—while minerals are inorganic. Minerals are vital not only as dietary nutrients but also serve numerous functions within the body. They act as building blocks for bones, influence muscle and nerve activity, and help regulate the body’s water balance.
Additionally, minerals are essential components of hormones, enzymes, and other biologically active compounds. Their role is crucial in maintaining the optimal functioning of the immune system, affecting both innate and adaptive immune responses.
Herbs and botanicals
The terms “botanical supplement” and “herbal supplement” are often used interchangeably but have distinct meanings. A botanical supplement encompasses a broad range of plant-based products used for medicinal purposes. An herbal supplement specifically refers to those derived from plants considered “herbs,” commonly utilized for culinary and medicinal properties.
While some consumers believe that products labeled as natural are inherently safe, this assumption may not hold true. Factors such as its chemical composition, physiological effects, preparation methods, and dosage influence the safety of a botanical product.
Botanicals can have varying effects, ranging from mild to powerful. Botanicals with mild actions, such as chamomile and peppermint, are often consumed in teas. Experts consider these safe for most individuals. In contrast, powerful botanicals can produce immediate effects. For example, green tea, a natural source of caffeine, provides a strong stimulant effect shortly after consumption.
Herbal-drug interactions can be a source of significant adverse effects. They should be evaluated when recommending or evaluating a patient’s medical history. Many interactions involve alterations in the metabolism of other drugs, such as the induction of CYP enzymes or P-glycoprotein functioning.
Patient recommendations for dietary supplements
When recommending products to patients, seek unbiased and scientifically sound research to substantiate the clinical benefits of each ingredient. Selecting products containing the USP certification or products that have undergone third-party verification can ensure the purity and contents of each product.
While many patients view dietary supplements as safe and effective, it is important to provide education and up-to-date information to ensure the safety of patients. Finally, specifically asking about the use of herbal supplements can help prevent unwanted adverse events and facilitate the safe usage of these products.
