Dietary Supplements: What You Need to Know | Consumer Health Information Corporation

Dietary Supplements: What You Need to Know

George O. Ofosu, PharmD Candidate 2007
Virginia Commonwealth University
Prepared during Consumer Health Information Corporation Clerkship

McLean VA

Millions of people take supplements with the hope of living longer or having a healthier life. It is estimated that about 150 million Americans take dietary supplements regularly.

Pharmacists and other healthcare professionals receive a lot of inquiries about dietary supplements. This shows that consumers want to know more about the dietary supplements they are taking.

Dietary supplements, by law, are products taken by mouth that contain ingredients to enhance the diet. Dietary supplements are more than vitamins and minerals. The dietary ingredient may be a vitamin, mineral, amino acid, a concentrate, metabolite, extract, enzyme, herb or other botanical. They come in a variety of forms such as tablets, capsules, powders, energy bars or drinks.

Any dietary supplement can be purchased without a prescription. Unlike prescription medications, they are not required to go through clinical testing to establish their safety and efficacy. They are assumed to be safe unless proven otherwise. Therefore, dietary supplement manufacturers can market their products without having to first get approval from the U.S. Food and Drug Administration (FDA), the federal agency that oversees the dietary supplement industry.

The FDA has no power over which dietary supplements enter the market. However, the FDA does have the power to have a supplement withdrawn from the market if it is determined to be dangerous and unsafe to use. Usually, the FDA starts an investigation into the safety of a dietary supplement after receiving complaints about side effects from consumers and healthcare professionals. That is why it is very important to report any unusual symptoms you experience after taking a dietary supplement to the FDA at 1-800-FDA-1088 or http://www.fda.gov/medwatch/how.htm.

Dietary supplements are not expected to cure or treat diseases. Manufacturers of dietary supplements cannot make such claims. They can, however, promote their product by claiming that it can help to reduce the incidence of a disease or related condition. For instance, a calcium supplement manufacturer can legally claim that calcium may reduce the risk of osteoporosis or that calcium helps build stronger bones. The manufacturer cannot claim that the calcium supplement can prevent or cure osteoporosis.

Many dietary supplements are marketed without going through the extensive testing in clinical trials that is required of prescription drugs. As a result, manufacturers of herbal supplements sometimes make claims based on their own interpretation of studies without having to submit that evidence to the FDA for approval. This has created some concern within the Federal Trade Commission (FTC). In 2003, the FTC sent over 280 advisory letters to different retailers of dietary supplements that were identified as making questionable claims about their products, warning that their Internet website claims must be supported by scientific evidence. The absence of such scientific evidence makes it difficult for consumers to really know whether the supplement is safe or if it contains the listed on the label.

Here are some steps to take before choosing a dietary supplement:

Talk to your pharmacist or doctor about any dietary supplements you are taking or considering taking since the ingredients in these products can interact with prescription or over-the-counter medications you may be taking.
While some people may benefit from certain supplements, there can also be a potential risk associated with using them. Many dietary supplements on the market contain substances that can be harmful or life-threatening when taken with some prescription or over-the-counter medications. For example:
- A combination of the prescription heart medication digoxin and a supplement containing calcium can lead to improper heartbeat and heart failure.
- A supplement that contains vitamin K, when taken together with the blood thinner medication warfarin (Coumadin®), can prevent the blood from being "thinned" and lead to clots. This can be life-threatening.
- The supplement St. John's Wort can reduce the potency of a class of antidepressant medications called SSRIs (e.g. Prozac®, Paxil®, Celexa®, Zoloft®) when they are taken together. Patients may need higher doses of the prescription medication for it to be effective.
Be cautious about label claims. Labels that sound "too good to be true" usually are. Examples of false product claims might include that the product can "cure all," "treat" or "cure" a disease, or help you to "lose weight easily," or that the product is "totally safe" or has "no side effects."
Look for the United States Pharmacopoeia (USP) label. This label indicates that the product has been voluntarily tested for purity, identity, and potency by the USP, a non-profit organization that sets standards for pharmaceuticals in the USA. It also indicates that the manufacturing process and package inserts have been similarly verified by the USP.
Do not be mislead by media headlines that encourage you to buy dietary supplements. Health advice from healthcare professionals is usually based on research over time rather than a single study that the media is excited about.

In the absence of rigorous clinical trials required by the FDA to establish the safety and efficacy of a dietary supplement before it enters the market, the burden lies with the consumer to make informed decisions and choices on what dietary supplements to take and when to take them. While there are a lot of supplements on the market that may make false claims as to their benefits, there are also quality products on the market that can help to promote good health outcomes. But until it becomes a requirement to first establish the quality and efficacy of a supplement before it is put on the market, most of that work will have to be done by the consumer, preferably with the assistance of a medical doctor or a pharmacist. As a consumer, your best protection is curiosity and scrutiny.