Dietary supplements are products other than tobacco that are intended to supplement the diet through means of ingestion. Examples of common types of dietary supplements include vitamins, minerals, herbals, and amino acids. Dietary supplement use is increasingly common. In 2017–2018, nearly 60% of adults 20 years of age or older in the United States reported using a dietary supplement in the previous month. Women tend to use more supplements than men, and overall dietary supplement use increases with age. Women 60 years of age or older are among the greatest users of dietary supplements. Herbal supplements, often referred to as botanicals, are among the most common dietary supplements used by those 20 to 59 years of age (Figure 1) [1].

In 2020, U.S. supplement sales soared, surpassing $10 billion for the first time ever. U.S. retail sales of herbal supplements totaled $11.3 billion, representing a 17.3% increase from the previous year. This surge was particularly fueled by the sales of supplements touted for immune health, stress relief, and heart health, likely related to the COVID-19 pandemic sweeping the globe [2].

While topical use of ACV has been suggested for acne, wound disinfection, eczema, dandruff, shingles, insect bites, and sunburns, topical application may actually be unsafe. Mild skin irritation is common, and multiple cases of chemical burns have been reported [3].

Ashwagandha has been shown to stimulate thyroid hormone synthesis and/or secretion, increasing serum triiodothyronine (T3) and thyroxine (T4) concentrations and reducing serum thyroid stimulating hormone (TSH) levels [4]. This might exacerbate hyperthyroidism. Recommend that patients with hyperthyroidism or those being treated with thyroid hormones use ashwagandha with caution.

Echinacea species are members of the Asteraceae family. Those with a genetic tendency toward allergic conditions (atopy), such as eczema, and those who are sensitive to other members of this family, which include ragweed, chrysanthemums, marigolds, and daisies, seem to be at higher risk for allergic reactions to echinacea [5]. Allergic reactions, including urticaria, runny nose, dyspnea, bronchospasm, acute asthma, angioedema, and anaphylaxis, have been reported with various echinacea preparations.

When adverse effects do occur, they are likely due to the ingestion of raw (i.e., uncooked) and unripe green berries. These, along with the seeds, leaves, and other plant parts, contain cyanogenic glycosides that can lead to adverse GI effects (e.g., nausea, vomiting, severe diarrhea), weakness, dizziness, numbness, and stupor. In some patients who are allergic to grass pollen, elder tree pollen might cause an allergic reaction characterized by rhinitis and dyspnea [6].

Turmeric is a spice that is commonly used in cooking. It is also used in traditional Chinese and Indian medicine. Turmeric is derived from the rhizome or root of the turmeric plant (Curcuma longa), which is a perennial herb and a member of the Zingiberaceae (ginger) family. Curcumin, a curcuminoid and the primary active constituent of turmeric, is what gives turmeric its distinctive yellow color [7].

Studies typically evaluate the use of turmeric supplements, not just ground turmeric as a spice. Supplements are often extracts and are usually standardized to curcuminoid (generally curcumin) content [7].

The global prevalence of nonalcoholic fatty liver disease (NAFLD) is estimated to be around 25%, so the search for potential treatments is on the rise. Clinical research in adults with NAFLD shows that taking curcumin daily reduces NAFLD severity in 30% to 79% of patients, compared with only 5% to 28% with placebo. It also attenuated additional fat deposition in the liver to only 0% to 5%, compared with 18% to 26% in those taking placebo [7]. Metabolic parameters (e.g., liver enzyme levels, BMI, blood glucose levels, HbA1c, lipid levels) also seem to be improved. Variability in some of the specific end points of individual studies might be due to differences in the formulations studied or the duration of treatment.

Emphasize that weight loss is the cornerstone of treatment for NAFLD, but if patients are asking about supplements, a trial of turmeric might provide some small, but encouraging, additional improvements [7].

Like echinacea, turmeric is of interest and has been studied for a variety of other uses, but the research for many of these other conditions is currently limited or conflicting.

Increases in the international normalized ratio (INR) have also been observed in cases of patients taking turmeric in combination with warfarin. Use turmeric with caution in patients taking anticoagulant or antiplatelet drugs, herbs, and supplements [7].

Ashwagandha has abortifacient effects and is unsafe for use during pregnancy. Recommend that patients avoid ashwagandha during pregnancy [4].