Meridian Medical Group

Quality and Standards in Dietary Supplements by Dr. Raymond Chang, M.D., F.A.C.P.

A dietary supplement can be defined as anything that is not a drug nor a food and can be consumed as an adjunct or addition to the diet. This expansive American concept of "dietary supplement is a confusing one, since it generally encompasses vitamins, herbs, functional foods, nutraceuticals, minerals, and combinations of the above 1. These categories are imprecise and not mutually exclusive. An herb may be a food in some cultures and can certainly contain vitamins, minerals, and other bioactive ingredients. A food (eg, garlic), on the other hand, may also be a supplement if extracted and presented in a pill or capsule form.

Prevalence and Forms of Dietary Supplements
There is a bewildering array of supplements in the health-food stores. Adding to the Confusion of defining supplements is the issue of quality control and standardization. It is difficult to sift through the thousands of different supplements currently on the market, let alone choose among the many different brands, strengths, and formulations of similar supplements. Such confusion in definitions and products calls for enhanced standardization and quality control.

The supplements industry is a large and rapidly growing business 2. One source estimates gross revenues of $6 billion in the US alone 3. Since there are many patients and consumers using supplements, practitioners need to know with some degree of reliability their indications, dosages, side effects, interactions, and contraindications. One major impediment to advances in this area is a general lack of standardization and quality control, in part because the Federal Food, Drug, and Cosmetic Act as amended by the Dietary Supplement Health and Education Act of 1994 (DSHEA) does not specifically require standardization or quality control in the manufacturing process beyond requiring supplements to be safe, clean, and wholesome 4.

First steps toward guaranteeing some consistency in ultimate product function or content would be implementation of production and material standards for supplements parallel to the United States Pharmacopeia (USP) for pharmaceuticals, the Inter- ¡¤national Standards Organization (ISO) series for industry, or Good Manufacturing Practices (GAP)') for manufacturing. This is particularly important so researchers can compare results of studies, practitioners can rationally apply and recommend products, and consumers can make intelligent choices of products.

Simple Moleculars versus Complex Biomasses
In essence, all supplements can be considered either "simple moleculars" or "complex biomasses." A simple molecular supplement is a vitamin, a mineral, or a single pure molecular substance such as melatonin or Coenzyme Q 10. Complex biomass supplements are natural animal or plant derivatives such as gingko, ginseng, thymus, or cartilage. The complex biomasses are characterized by multiple ingredient compounds, the contents and functions of which generally vary based on multiple factors.

For example, the active ingredient of a plant-derived material may depend on its location in the plant (leaf, stem, root, etc), the season in which it is harvested, the lighting condition of its growth, soil conditions, latitude, and so forth 5. A wine made from a certain variety of grapes (a complex biomass) can taste different from year to year and from place to place depending on climate and geography. Other factors that affect the final product include the extraction method (eg, water, alcohol, or glycerol) and formulation (eg, tablet, capsule, or elixir) as well as pharmacokinetic issues such as absorption, bioavailability metabolism, and excretion (half-life).

Obviously, standardization is much more difficult with complex biomasses than with simple moleculars. Such standardization is dismally lacking in the self-regulated and profit-driven health supplement industry.

Standardization
Standardization can be implemented at four levels: a) the species of the animal or plant (ie genetics), b) the precise growth conditions or definition of habitat, c) the extraction or formulation process, and d) the product itself. Standardization of a product itself is meant to be the manufacturer's or a regulatory agency's assurance of the product's content or function. But currently neither federal nor state governments mandate even such minimal requirements as routine and repeated assay for heavy metal or bacterial contamination of supplements.

Specifically, we can achieve content standardization of a product by specifying a certain minimal amount of a key marker content (eg, 24 percent gingko bioflavonoids for gingko biloba products) as determined by chromatography or other assay methods. We can achieve function standardization with bioassays (eg, the chick chorioallantoic membrane test for antiangiogenesis in shark's cartilage 6). Furthermore, good manufacturing practices should be mandatory. Standards should be set and claims examined for packaging and labeling.

Ultimately, the efficacy of supplements In various clinical states will have to be demonstrated in human clinical trials, and safety should be guaranteed by improved and strictly enforced quality controls in materials and manufacturing. Consumers, health care providers, the health supplement industry, and the government will need to work together to define the standards and systematically examine all supplements in the interest of the public.

References