Dietary Supplements

Many patients consider using dietary supplements such as vitamins, herbs, or other plant products as part of their cancer treatment. Currently, few governmental standards are in place to control the production and ensure the safety, effectiveness, and quality of dietary supplements. Patients must understand that dietary supplements, like medications, have potential risks and side effects. They can usually be used safely within certain dosage guidelines (Smith, 2005). But, unlike drugs, dietary supplements are primarily self-prescribed with little or no input from an informed healthcare provider. Often, insufficient reliable information is available about the safe use and potential risks of dietary supplements.

Dietary supplements such as vitamins, herbals, and botanicals are sold over the counter without a prescription, while medications are more closely regulated and controlled. Both have the potential for significant side effects and interactions with other supplements and medications. Patients often make the mistake of assuming that because supplements are sold over the counter, sometimes with little or no direction on the label, they are completely safe to take, even in high doses. In fact, large doses of some vitamins or minerals can be dangerous and toxic. Another common misconception is that if the substance is natural, then it is safe (Mayo Clinic, 2007).

Many people also assume that dietary supplements can safely be taken along with any prescription drug. This is also not true. Most drug companies and producers of herbal supplements do not research possible drug interactions, so the risks of taking supplements with many medications are unknown.

All over-the-counter and prescription drugs are regulated in the United States by the FDA. Because dietary supplements (including all forms of botanicals and vitamins) are not considered drugs, they are not held to the same strict safety and effectiveness requirements that are applied to other drugs (Smith, 2005). The following should be considered when purchasing supplements.

• When shopping for supplements, the patient should look for USP or NF on the package label. The U.S. Pharmacopeia–National Formulary (USP-NF) is a book of public pharmacology standards. It contains standards for medicines, dosage forms, drug substances, medical devices, and dietary supplements.
• When shopping for a botanical, the patient should make sure to find a product that uses only the effective part of the plant. Avoid botanicals that have been made using the entire plant, unless the entire plant is recommended.

• The patient should consider the name and reputation of the manufacturer or distributor. Is it a nationally known name? Large companies with a reputation to uphold are more likely to manufacture their products under strict, quality-controlled conditions.
• The label should provide a way to contact the company if there are questions or concerns about the product. Reputable manufacturers will provide contact information on the label or packaging of their products.

Patients should try to avoid mixtures of many different supplements. The more ingredients, the greater the chances of harmful effects.

Smith, A. (2005). American Cancer Society’s complementary and alternative cancer methods handbook (2nd ed.). Atlanta, GA: American Cancer Society.

Mayo Clinic. (2007). Mayo Clinic book of alternative medicine: The new approach to using the best of natural therapies and conventional medicine. New York, NY: Time.