Stephen M. Setter, PharmD, CDE, CGP, FASCP
Joshua J. Neumiller, PharmD, CGP, FASCP
College of Pharmacy
Washington State University
Spokane, Wash.

Abstract

Herbal products and dietary supplements are increasingly being used for various medical conditions, including diabetes mellitus. The following article provides tips and clinical pearls for the practicing dietitian to call upon when consulted by patients with diabetes who wish to use herbal and dietary supplements. This article will outline good manufacturing practices, tips on purchasing and taking supplements, and a brief discussion on the safety and appropriate monitoring of herbal and dietary supplements. The reader will be referred to reference materials and helpful websites when appropriate.

Full Article

Introduction

Herbal supplement sales in the United States exceeded $4.7 billion in 2007, with steady increases in sales volume reported over the past three years (1). Studies suggest that more than 20% of Americans use alternative therapies, and use may be even higher among the Hispanic, Native American or Asian populations (2). People with diabetes are 1.6 times more likely to seek alternative medicines than those without diabetes. Therefore, the registered dietitian must have a working knowledge regarding the supplements used and their safety.

Good Manufacturing Practices

In 1994, Congress passed the Dietary Supplement Health and Education Act (DSHEA) permitting the sale of dietary supplements. This act allowed the classification of herbs as “dietary supplements” along with vitamins and minerals. It is important to realize that DSHEA allows for the marketing of herbs without any oversight in regard to safety or efficacy. Clients need to understand that herbal supplements have not undergone the rigorous Food and Drug Administration (FDA) safety and efficacy studies required for prescription medications.

The DSHEA also recommended that good manufacturing practices (GMPs) be used in the development of herbal supplements; however, this is not enforced by the FDA. Included in GMPs are a host of activities that are important for manufacturing a product free of defects such as quality assurance surrounding the use of raw materials, strict record-keeping guidelines, high standards for cleanliness and safety, employment of qualified personnel, in-house testing and production and process controls, and guidelines regarding storage and distribution of products.

Assessment of Safety and Safe Dosing

Americans believe that “natural” is synonymous with “safe,” but this is not necessarily the case. Dietary and herbal supplements are associated with multiple concerns, including potential drug interactions with prescribed medications, side effects, variability in composition among products, lack of product standardization, and possible contamination and/or product misidentification.

Open communication between the client and healthcare providers is crucial to good care outcomes. Recent estimates show that more than half of all clients do not disclose herbal and dietary supplement use to providers. Problems associated with supplement use can be avoided, minimized or managed if the healthcare team is aware of supplement and herbal use so that drug interactions can be screened and side effects monitored. Without the knowledge of herbal and other over-the-counter (OTC) products, physicians/healthcare providers may incorrectly associate side effects or health improvements with prescription medications, while overlooking the effects of the supplements. It is important forclients to understand that herbal products and dietary supplements vary in composition. Because dietary supplements do not undergo the same strict inspection requirements that prescription medications must pass, some products have been found to contain contaminants, such as heavy metals, microbes, and even radioactive materials.

How to Purchase

The bottom line when it comes to purchasing herbs is to find a reputable source that follows GMPs and preferably is regulated by an independent oversight organization. Working with an herbalist, pharmacist or other healthcare provider who specializes in herbal supplements is a good place to start. Interview the pharmacist or herbalist that you select or recommend, verifying the following:

• Does the retailer purchase from reputable sources that follow GMPs?
• Can the pharmacist or herbalist demonstrate active knowledge of recent scientific and evidencebased research related to herbal and dietary supplements? Can the retailer demonstrate continuing education related to complementary and alternative therapies?
• Does the pharmacist or herbalist provide detailed instructions on appropriate dosing, special instructions and potential risks related to product use?

Tips on Taking Supplements

Diabetes educators must be informed about alternative therapies and provide information to aid clients as they make decisions on dietary and herbal supplement use.

Tip 1: Explore why clients want to take supplements. Is it to improve blood glucose control, “treat” high cholesterol or high blood pressure, for anti-aging reasons, or for the latest promotion highlighted in the national news? Keep in mind that herbal supplements can in no way be marketed or labeled to treat a specific condition or disease.

Tip 2: Discourage off-brands or supplements that have not been evaluated by an independent agency. Reputable independent agencies include the Natural Products Association, ConsumerLab. com, NSF International, and the U.S. Pharmacopeia (USP). For example, the USP stamp of approval ensures that the supplement contains the stated ingredients in the stated amounts; will disintegrate or dissolve as it should; and has been screened for pesticides, heavy metals, and bacteria. Ultimately, the USP stamp provides the consumer with the peace of mind that GMPs were followed. In addition, supplements with the USP insignia will contain the statement, “USP has tested and verified ingredients, product and manufacturing process. USP sets official standards for dietary supplements.” National brands that tend to be reviewed by an independent regulator are numerous and include the product lines Nature Made, Nature Resource, Kirkland, Nutrilite, Perrigo, GNC, and TwinLab. Often the product will have a “seal of approval” by the independent regulator.

Tip 3: Advise clients to monitor blood glucose, lipid profiles, neuropathy or other stated claim and reason for taking the supplement.

Tip 4: Encourage clients to purchase only single-herb products that clearly show how much herbal content is in each dose, because many products are mixtures of multiple herbs with inadequate amounts of each.

Tip 5: Caution clients regarding claims that sound too good to be true. Often manufacturers of a particular product make outrageous claims. In addition, guide clients away from websites that overpromote supplements or make unfounded claims.

Tip 6: When starting a new supplement product, encourage clients to communicate this to their healthcare providers and pharmacists. Supplements can interact with OTC and prescription medications. Every member of the healthcare team should screen for potential drug-drug and drugnutrient interactions at each visit or assessment.

Natural vs. Organic vs. National Brand

Simply put, “natural” does not equal “safe.” Arsenic is natural, as is lead. Organic usually means that plantshave been grown without pesticides or artificial fertilizers and do notcontain artificial additives. Some people believe that organically grown products are healthier and safer; the decision to use organic products is ultimately up to the consumer. National brand products typically have excellent quality control and strive to be consistent and safe.

Monitoring of Efficacy and Side Effects

Whether a supplement is being used as an adjunctive treatment for diabetes or an unrelated purpose, it is always a good idea for individuals with diabetes to check blood glucose levels more frequently when they start taking a new product that may affect glycemic control. Table 1 provides a list of herbal and dietary supplements associated with hypoglycemia, hyperglycemia, or both, as side effects, according to the Natural Medicines Comprehensive Database and Clinical Pharmacology Online. Encourage clients to keep detailed records of products and doses taken, comments regarding side effects and detailed blood glucose records. The more detailed the records, the better for the physician or healthcare provider to review when comparing the effect of prescription medications with that of OTC products. The physician may need to participate in herbal supplement evaluations by checking lipid profiles. The client may need to monitor blood pressure, weight, neuropathy symptoms or other parameters to demonstrate efficacy of the herbal therapy. Last, but certainly not least, encourage clients to try one product at a time. If a client begins multiple products at once, it becomes difficult to determine which ingredient is contributing to benefits or side effects that are observed.

Table 1. Natural Products (Herbs/Supplements) Associated With Hypoglycemia and Hyperglycemia.

Helpful Websites*

Summary

Patients with diabetes use a plethora of natural products to assist with blood glucose control and other comorbidities. This makes it very important for the registered dietitian to provide information regarding GMPs, tips on purchasing, and safe use of these products with appropriate monitoring.

Additional Resources

Clinical Pharmacology Online. Available at http://www.clinicalpharmacology.com. Accessed July 7, 2008.

ConsumerLab.com. Available at http://consumerlab.com. Accessed June 25, 2008.

Egede LE, Ye X, Zeng D, Silverstein MD. The prevalence and pattern of complementary and alternative medicine use in individuals with diabetes. Diabetes Care. 2002; 25:324-329.

FDA Fact Sheet. Dietary supplement current good manufacturing practices (CGMPs) and interim final rule (IER) facts, June 2007. Available at: http://www.cfsan.fda.gov/~dms/dscgmps6.html. Accessed July 25, 2008.

Herbmed website. Available at: http://www.herbmed.org/. Accessed July 25, 2008.

Natural Medicines Comprehensive Database. Available at: http://www.naturaldatabase.com. Accessed July 7, 2008.

National Products Association website. Available at http://www.nnfa.org/site/PageServer?pagename=ic_gmp. Accessed June 26, 2008.

NSF International. NSF dietary supplements certification program. Available at http://www.nsf.org/consumer/dietary_supplements. Accessed June 26, 2008.

Shane-McWhorter L. Biological complementary therapies in diabetes. In: American Association of Diabetes Educators, Mensing C, ed. The Art and Science of Diabetes Self-Management Education: A Desk Reference for Healthcare Professional. Chicago, Ill.: American Association of Diabetes Educators; 2006.

Shane-McWhorter L. Complementary & Alternative Medicine (CAM) Supplement Use in People with Diabetes: A Clinician’s Guide. Alexandria, Va.: American Diabetes Association; 2007.

U.S. Pharmacopeia. USP dietary supplement verification program overview. Available at http://www.usp.org/USPVerified/dietarySupplements. Accessed June 26, 2008.

National Center for Complementary and Alternative Medicine, National Institutes of Health, U.S. Department of Health and Human Services. What is complementary and alternative medicine? Available at http://nccam. nih.gov/health/whatiscam. Accessed June 27, 2008.

Yeh GL, Eisenberg DM, Kaptchuk TJ, Phillips RS. Systematic review of herbs and dietary supplements for glycemic control in diabetes. Diabetes Care. 2003;26(4):1277–1294.

References

1. Blumenthal M, Cavaliere C, Rea P. Herbal supplement sales in United States show growth in all channels. Herbalgram. 2008;78:60-63. Available at: http://content.herbalgram.org/wholefoodsmarket/herbalgram/articleview.asp?a=3263. Accessed August 26, 2008.

2. American Association of Diabetes Educators. The Art and Science of Diabetes Self-Management Education: A Desk Reference for Healthcare Professionals. Chicago, Ill.: American Association of Diabetes Educators; 2006; chap. 19.