Complementary and Alternative Medicine (CAM) Supplement Use in People with Diabetes: A Clinician's Guide. Laura Shane-McWhorter
dietary supplements to forego the same stringent approval process that is required for drugs, and therefore proof of safety and efficacy is not required for marketing.
The reclassification has resulted in a serious consequence. Sometimes contaminants or substitutes have been found in the products. For instance, as noted above, some diabetes products have been contaminated with lead,29,30 and other products touted as being “herbal” have been found to contain prescription drugs such as chlorpropamide or glyburide.28,48
A possible solution would be the use of standardized products. Standardization guarantees that each dose provides a consistent level of the active ingredient. However, proponents of biological complementary therapies argue that standardized extracts may not always contain all of the therapeutic ingredients found in the natural product. A pertinent factor is whether the standardized preparation actually reflects the labeled information.22
DSHEA allows manufacturers of dietary supplements to make claims regarding the ability to maintain “structure and function” of the body, but does not allow claims regarding diagnosis, treatment, cure, or prevention of disease.47 If a manufacturer claims the product affects body structure or function, the label must include the following statement: “This statement has not been evaluated by the Food and Drug Administration (FDA). This product is not intended to diagnose, treat, cure, or prevent any disease.” The manufacturer must also notify the FDA within 30 days after a product is on the market if it bears such a label.
FDA has implemented regulations that ban implied as well as expressed disease claims.47 For example, claims made by a manufacturer that a patient could misconstrue as indicating treatment or prevention of a disease are no longer allowed. In the new regulations, a product may make health maintenance claims but not disease claims (“maintains a healthy prostate” is allowed, but “treats benign prostatic hyperplasia” is not).
FDA has published a Dietary Supplement Strategy (Ten Year Plan).49 The year 2010 is the target year when FDA will have a “science-based regulatory program that fully implements DSHEA, in an effort to provide consumers with a high level of confidence in the safety, composition, and labeling dietary supplement products.” This program will assist clinicians in providing better information to people with diabetes who use CAM supplements.
TESTING CAM SUPPLEMENTS
An unfortunate situation is that most consumers believe that dietary supplements are evaluated for content and efficacy by an appropriate regulatory agency. The Harris Poll conducted 1,010 telephone interviews with a cross-section of adults in October 2002. The poll indicated that 68% of Americans believe the government requires herbal manufacturers to report potential dangers or adverse effects.50 Additionally, 58% believed that government agencies, such as the FDA, must approve herbal products before sale to the public, and 55% believed that manufacturers cannot make claims for supplement safety or efficacy without scientific evidence. Additionally, 13% believed that because supplements are “natural” they are safe.50 Actually, supplement manufacturers, not the FDA, are responsible for determination of safety and veracity of label claims. Most individuals do not realize that manufacturers do not have to tell the FDA or consumers what evidence they have about supplement safety or to back up their claims.51
Accuracy of labeling and ingredient purity may now be assessed by different dietary supplement testing programs. Unfortunately, efficacy is not evaluated. An example of an organization that has established certification programs for dietary supplements is the U.S. Pharmacopeia (USP). The USP program is called the Dietary Supplement Verification Program.52 The “USP-verified mark” on the label indicates the product ingredients are accurate and that the product is pure, will dissolve properly, and has been manufactured using good manufacturing practices. Clinicians should note that the USP website also lists manufacturers that have undergone the evaluation process.52
NSF International (formerly known as National Sanitation Foundation) also verifies products for label and content accuracy, checks purity and contaminants, and audits the manufacturing process for good manufacturing practice compliance.53 Consumer Lab also tests supplements.54 It tests certain classes for purity and accuracy of labeled ingredient content. All of these companies require that manufacturers pay for testing.55 The Consumers Union also tests certain products and reports findings in their publication, Consumer Reports.56 The National Nutritional Foods Association (NNFA) has also launched a good manufacturing practice program. Recently, NNFA changed its name to the Natural Products Association, and more information may be obtained at their website.57
EVALUATING CLAIMS FROM MANUFACTURERS OF DIETARY SUPPLEMENTS
Manufacturers may use deceptive marketing tactics to promote their products. Clinicians may wish to access the FDA website that provides suggestions on “How to Spot Health Fraud.”58 One caveat provided by the website is to be wary of a single product claiming benefit for a variety of unrelated diseases (for instance, difficulties ranging from menstrual problems to asthma to rheumatic complaints). Other caveats are to be wary of evidence of benefit based on personal testimonials, claims of unusually rapid benefit, or use of meaningless phrases that may sound scientifically impressive to lay consumers who do not have the education or training to determine veracity.
The FDA Center for Food Safety and Applied Nutrition has established two websites for consumers to evaluate information about dietary supplements. “Tips for the Savvy Supplement User”59 includes basic points to consider, such as talking with a health care provider before using a supplement, broaching the issue that some supplements may interact with prescription or over-the-counter medicines or have untoward effects during surgery. It also provides information on how to report adverse effects of dietary supplements. Furthermore, it provides tips on searching the Web for information on dietary supplements, such as how to find out who operates the site, the purpose of the site, the information sources and references, and whether the information is current. Another website, “Tips for Older Dietary Supplement Users,”60 discusses potential risks, such as the danger of substitution of dietary supplements for conventional medications or the dangers associated with consuming greater than recommended amounts. It also advocates discussion of dietary supplement use with the patient’s health care provider. It provides a checklist of important considerations such as issues with side effects, drug interactions, and possible discontinuation before scheduled surgery.
The following includes excerpts from The Health Professional’s Guide to Popular Dietary Supplements61 and provides other information that may help clinicians:
Nationally known companies generally have more stringent quality assurance and incorporate good manufacturing practices. Some companies may even import products tested in Europe. A list of these is included in The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines.62
The following questions may elucidate useful information when contacting a manufacturer:61
