special subjects
Overview of Dietary Supplements
Purity and Standardization
Lack of regulation and government monitoring also means that supplements are not monitored to ensure that they contain the ingredients or amount of active ingredient the manufacturer claims they contain. The supplement may have unlisted ingredients, which may be inert or harmful (eg, natural toxins, bacteria, pesticides, lead or other heavy metals, unapproved dyes), or it may contain variable amounts of active ingredients, especially when whole herbs are ground or made into extracts. Consumers are at risk of getting less, more, or, in some cases, none of the active ingredient, if the active ingredient(s) is even known. Most herbal products are mixtures of several substances, and which ingredient is the most active is not always known. The lack of standardization means not only that products from different manufacturers may vary, but also that separate batches produced by the same manufacturer may differ. This product variability is a particular source of difficulty in conducting rigorous clinical trials and comparing the results among different trials. However, some supplements have been standardized and may include a designation of standardization on the label. New regulations governing supplement production in the US include rules for Good Manufacturing Practices (GMPs). These rules strengthen standards for keeping manufacturing facilities and equipment clean and raw materials pure and uncontaminated. GMPs also ensure proper labeling, packaging, and storage of the finished product. 