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| Dietary Supplements: How To Know What Is Safe | |
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What you need to know first If you are thinking about using dietary supplements such as vitamins, herbs, or any product made from plants (botanicals) as part of your cancer treatment, you will want to know more before you decide what you want to do. This information is offered to help you learn more about dietary supplements so you can make a more informed decision about using them safely. Risks and side effects Like drugs, dietary supplements have risks and side effects. They can usually be used safely within certain dosage guidelines. But, unlike drugs, dietary supplements are mostly self-prescribed, with little or no input from informed medical sources like doctors, nurses, or pharmacists. There is a lot of wrong information out there. Even for those who are well informed, it can be hard to find reliable information about the safe use and potential risks of dietary supplements. As part of its function to monitor supplement safety, the U.S. Food and Drug Administration (FDA) gathers reports of illness, injury, or reactions from supplements. But before December 2007, supplement makers were not required to report serious harmful effects to the FDA, so most of these events were not reported. This means there is a large gap in reports, but this should improve in the future. Looking to other sources of information, exposures to supplements (such as vitamins and herbs or botanicals) accounted for nearly 26,000 calls to U.S. poison control centers in 2007 alone. Of these calls, there were more than 600 moderate to severe outcomes, and 1 death. More than 1,500 of these cases were described as "adverse reactions," and more than 3,000 were treated in health care facilities. Since most people who suffer unexpected side effects, illnesses, or drug interactions from dietary supplements do not call a poison control center, this is likely to be a very low estimate of actual events. Used properly, certain dietary supplements may reduce the risk of some diseases, relieve or reduce discomfort caused by certain drugs or conditions, or simply make you feel better (improve your quality of life). But taking dietary supplements can be risky, especially for people who are getting cancer treatment. Special problems for people getting cancer treatment There are several ways that supplements can cause problems for people during cancer treatment. For example, some dietary supplements can cause skin sensitivity and severe reactions when taken during radiation treatment. Patients who are having radiation treatments should talk to their doctors before taking any supplement. And, patients receiving chemotherapy may be at higher risk for drug interactions if they take dietary supplements. Cancer experts often recommend that these patients avoid dietary supplements altogether until their cancer treatment is over. But if you decide to take supplements anyway, be sure to let your doctor know exactly what you are taking. Dietary supplement advertising and promotion Keep in mind that a great deal of what you hear or read about dietary supplements is based on anecdotal evidence -- that is, evidence based on people's (even doctors') personal experiences or opinions rather than objective, controlled scientific studies. Be skeptical of sources that make grand claims based on a few people's testimonials or vague references to "scientific proof." The rule "if it sounds too good to be true, it probably is" usually applies to such claims. Remember also that the makers and sellers of supplements have a financial interest in promoting their products. Look for evidence or research on the supplement from objective, third-party sources. See our information Complementary and Alternative Methods for Cancer Management to learn more. You can read it on our Web site or call us for a copy. Talking with your doctor Regardless of your treatment, it is always safest to talk with your doctor about the amount of each supplement you plan to take before you start. If you have been taking supplements and want to continue to do so, it is important that your doctor know this, too. Many doctors are just starting to learn about the uses, risks, and potential benefits of dietary supplements. In some cases, this can cause problems between patient and doctor when it comes to using supplements along with a mainstream treatment. This situation should improve as more studies are done and better information becomes available. We encourage you to gather as much information as possible on the dietary supplement you are thinking about. Then, approach your doctor with the information you have, and ask for an open conversation. Ask for his or her professional opinion as to whether the treatment is safe and medically sound, and how it might be safely used along with your cancer treatment. Remember to make sure that your doctor knows about other medicines, vitamins, and supplements that you are already taking. Common misconceptions about dietary supplements Megadosing: The "More is better" myth Many people wonder why dietary supplements like vitamins, herbals, and botanicals are sold without a prescription from a doctor, while medicines (or drugs) are more closely regulated and controlled. People 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 the 1990s there was a trend of "megadosing" antioxidants such as vitamin C, beta carotene, and vitamin E. Even though no scientific studies have ever proven that large doses of vitamin C can prevent or cure colds, many people still think this is true. You may have heard a number of claims about the benefits of taking large doses of certain vitamins. But the practice of using large doses of vitamins to fight disease in humans is not supported by the available scientific evidence so far. In fact, large doses of some vitamins or minerals can be dangerous and toxic. For example, too much vitamin C can interfere with the body's ability to absorb copper, a metal that is essential to our body chemistry. Also, too much phosphorous can inhibit the body's absorption of calcium. Large doses of vitamins A, D, and K are not eliminated quickly by the body and can easily reach toxic levels when too much is taken. Talk with your doctor before taking large doses of any vitamin, mineral, or other supplement. Your nurse or pharmacist may also be able to give you more information on safe dosages. Even when vitamin doses are not high enough to cause toxic effects, the overall impact on health may be negative. For example, several large studies found that, on average, people taking vitamin E supplements lived no longer than those who didn't. Some even died sooner, particularly of heart failure. The "Natural is safe" and "Natural is better" myths In today's cultural climate, you will not find much support for the idea that a man-made or refined substance is better or safer than one sold in its unrefined, natural state. But supplements that claim to be "all natural" are not always better or safer than refined or manufactured substances. Keep in mind that some of the most toxic substances in the world occur naturally. Poison mushrooms, for example, are completely natural but not safe or helpful to humans. Many plants in nature are toxic, even deadly, if taken internally. Botanical supplements (such as garlic, ginger, ginkgo biloba, echinacea, and others) are made of plant material, so many of them are sold as "natural" products. But plants are made up of many chemicals. Some of these chemicals can be helpful while others are poisonous or can cause allergies in humans. Botanicals that market themselves as "all natural" are not always the most helpful ones, since they are not refined to remove potentially harmful chemicals. Botanicals can contain any or all parts of the plant, including roots, stems, flowers, leaves, pollen, and juices. Different parts of plants can have very different effects on humans. For example, dandelion root is a laxative (it causes bowel movements), while dandelion leaves contain a diuretic (a chemical that increases urination). If you decide to use a botanical supplement, make sure you know what parts of the plant were put into it. If you are unsure, contact the company and ask them how they make their supplement. Remember, too, that safety and dose are related. The leaves or roots of some plants can be safely consumed in small amounts as an herb. But concentrated extracts sold as liquids or pills may contain the plant's chemicals in far greater amounts and may not be safe. The "It's been used for thousands of years, so it must be good" myth Knowing that a botanical has been used in folk or traditional medicine for thousands of years is helpful, but is not convincing proof of safety. If small amounts of a plant caused painful or life-threatening side effects right away, its use is unlikely to have persisted in folk medicine or traditional medical systems. But traditional medical systems thousands or even hundreds of years ago did not have the scientific methods to detect long-term side effects. So, if a plant seemed useful over the short term but actually increased the risk of chronic disease (like cancer, heart failure, or kidney failure) after years of use, those side effects would not have been noticed. It is also helpful to find out whether a plant is being used now like it was in its traditional use. For example, tea prepared from a certain plant might have been safely used in traditional Chinese medicine to treat occasional bouts of asthma when given by an experienced practitioner. On the other hand, daily use of much higher doses taken in a concentrated form with no expert supervision might be quite unsafe. The "It can't hurt to take supplements with my regular medicines" myth Many people assume that dietary supplements are always safe to take along with prescription drugs. This is not true. For example, certain botanicals can block or speed up the body's absorption of some prescription drugs, causing the person to have too much or too little of the prescribed drug in their bloodstream. Most drug companies and producers of herbal supplements do not do research on possible drug interactions, so the risks of taking supplements with many drugs are unknown. Talk with your health care team about any supplements you are taking or wish to take. Your doctor or pharmacist can tell you of any known interactions with medicines you may be taking. Unfortunately, there are always new drugs and supplements for which interactions have not yet been studied. Talk with your doctor or pharmacist about the chance of interactions if you are taking newer drugs or supplements. FDA regulation of drugs versus dietary supplements All over-the-counter and prescription drugs are regulated in the United States by the Food and Drug Administration (FDA). Because dietary supplements (including all forms of botanicals and vitamins) are not considered drugs, they are not put through the same strict safety and effectiveness requirements that other drugs are. FDA regulation of drugs In general, new drugs are considered by the FDA to be unsafe until they are proven safe by clinical trials. And the FDA must approve any new drug before it can be legally sold in the United States. Clinical trials are tests done under well-controlled conditions on human volunteers. These tests must be done even on drugs that are to be sold over the counter (without a prescription). The FDA approval process requires that the drug be proven in a series of several clinical trials. These clinical trials must show "substantial evidence" that the drug is both safe and effective for each of its intended uses. Once the FDA approves the drug, it must be manufactured under carefully monitored conditions and packaged with complete information on the best dose, route, and schedule. The package information must include a listing of known side effects, contraindications (special conditions under which using the drug would cause too much risk), or unsafe interactions with other drugs. Once the general public is using a new drug, doctors are required to report to the FDA any ill effects their patients may have. This data ensures that any side effects not seen in the clinical trials will eventually be found and kept track of for the safety of other people. FDA regulation of dietary supplements In 1994, the Dietary Supplement Health and Education Act (DSHEA) defined dietary supplements as a category of food, which put them under different regulations than drugs. They are considered safe until proven otherwise. Under the DSHEA, dietary supplements cannot contain any ingredients that may have "a significant or unreasonable risk of illness or injury" when the supplement is used as directed on the label, or under normal conditions of use if there are no directions on the label. If a dietary supplement contains a new ingredient, the manufacturer must provide the FDA with adequate proof that the ingredient is safe before the supplement is marketed to the public. But manufacturers are not required to test new ingredients or supplements in clinical trials, which would help find risks and potential interactions with drugs or other substances. The DSHEA gives the FDA permission to stop a company from making a dietary supplement, but only when the FDA proves that the product poses a significant risk to the health of Americans. They are found unsafe only after they cause harm. This approach is the reverse of the way over-the-counter and prescription medicines are treated. Because dietary supplements are usually self-prescribed, there is no controlled system for reporting bad reactions and side effects. If a supplement has unknown side effects or interactions with other drugs, foods, or supplements, they are not likely to be discovered as quickly as those of new drugs on the market. What kinds of problems have there been with supplements and herbs? Since they became widely available in 1994, the FDA has found problems with some dietary supplements. Products such as herbs were sometimes tainted with germs, pesticides, or toxic heavy metals. Others did not contain what was listed on the label at all. Still others contained more or less than the amount claimed on the label. Vitamin supplements, for example, were sometimes found to contain much less than the stated amounts on the labels. Some "herbal" supplements have been found to contain prescription drugs that were not listed on their labels. These kinds of problems can cause serious health issues for the person who takes the supplement. Manufacturing guidelines for dietary supplements It is generally the manufacturer's responsibility to see that the supplements they make are standardized, quality products that meet the specifications described on their label. Many manufacturers have always followed careful, consistent production standards and market only high-quality, correctly labeled supplements. But less honest manufacturers, or those who are less careful, make supplements that contain little or none of the products listed on the label. Some supplements contain a larger dose than the label lists, possibly due to poor quality controls. There have even been reported cases of toxic products. New guidelines are already in place for the production of most dietary supplements, and will cover all supplement makers by 2010. As part of these regulations, in 2007 the Department of Health and Human Services put out a set of standards (called Good Manufacturing Processes, or GMPs) for producing dietary supplements. After the 2007 standards go fully into effect (in 2010), it is likely that most supplements will contain what the label says they do. But it's important to know that, even since the new rules started going into effect, there have been many times when supplements were tainted with real drugs or dangerous substances. How will the new FDA rules affect herbs and supplements? The 2007 FDA rules require that dietary supplements follow standards called Good Manufacturing Practices, or GMPs. This means that dietary supplements must:
The companies will still sell their products in much the same manner as before. But if companies are following the new rules, the supplements will be more likely to contain what is listed on the label. The new rules address the quality of manufacturing processes for dietary supplements and the accurate listing of their ingredients on the label. It is important to know what the new rules do not do:
Even so, the improvements in quality and label accuracy will make supplements less likely to cause harm as long as these rules are followed. These rules went into effect for large supplement makers in June of 2008, and mid-sized companies in 2009. They go into effect for the smaller supplement makers in June of 2010. It is important to remember that, like all laws, the new regulations will not stop dishonest or criminal sellers from selling supplements that are falsely labeled. It will be up to the FDA and other law enforcement groups to try and stop criminal manufacturers once they have been discovered. As quickly as some of these groups have been surfacing, that may be hard to do. See our document Complementary and Alternative Methods for Cancer Management for more information on quackery and fraud. New rules on dietary supplements help in some ways, but not others Though the law doesn't cover every supplement maker until 2010, the good news is that there are national standards in place that require careful production and help ensure the quality of dietary supplements. On the other hand, there are concerns about what is not changing under the new rules. For instance, there is no requirement that herbs and other substances be tested to find out how they affect the body, or how safe they are. And despite the rules, you still hear about products that are sold as herbs or "all natural" compounds, but are tainted with drugs or other harmful substances. So it falls to you, the consumer, to gather truthful information about using these products safely. The USP standard The U.S. Pharmacopeia (USP) is an independent organization dedicated to quality control for the strength, quality, and purity of pharmaceuticals. In 1997, the USP began publishing standards for dietary supplements. These standards focus on the strength, quality, purity, packaging, and labeling of dietary supplements and are updated yearly. The USP also does product testing and site visits for companies who join their program. Makers of dietary supplements are not required by law to follow USP standards, but many of them choose to do so anyway. The new FDA rule may not be as stringent as the USP standards, so companies that have used these standards before may continue to do so. You can still look for products that use USP standards. The label may have the initials USP after the name of the product, or contain a note that it conforms to USP standards. Some companies have the initials "NF" for National Formulary on their labels (The National Formulary is allied with USP, and has standards that more specifically relate to herbs and botanicals.) Some supplements even have both initials. Reading dietary supplement labels Before you buy a supplement, look at the label carefully. It is easy to misread the claims that are being made about the product. The manufacturers of dietary supplements are allowed to make 4 kinds of claims, which are explained below, on the labels of their products:
Nutritional claims: These are statements about the general effects dietary supplements, vitamins, and minerals have on diseases known to be caused by nutrient deficiency. For example, "vitamin C prevents scurvy." These claims do not need to be approved by the FDA. But the label must also state how many cases of the disease occur in the United States. Consumers must weigh the risk of getting scurvy against the potential risks of the supplement itself. Claims of well being: These are just that -- statements such as "makes you feel better." These claims also do not require pre-approval by the FDA. (See our document Complementary and Alternative Methods for Cancer Management and Placebo Effect for more information on these kinds of effects.) Health claims: These are statements about known health benefits of certain compounds. For example, risk-reduction claims such as "folate may reduce the chance of pregnant women delivering an infant with neural tube defects" fall into this category. The FDA must pre-approve all health claims, and requires that they be supported by evidence from scientific studies. Remember that risk-reduction claims are not the same as prevention claims. Structure or function claims: These are the most hotly debated and confusing to consumers. They are claims about the effect of the dietary supplement on the structure or function of the body. The FDA published a ruling in January 2000 that explained exactly what kinds of structure or function claims would be acceptable for dietary supplements. Dietary supplements may not make any claims regarding the treatment of disease. But the following product descriptions are acceptable as structure or function claims for dietary supplements:
Structure or function claims are not reviewed by the FDA. In fact, labels that carry them must also include the disclaimer "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease." The FDA requires this disclaimer on supplement labels because it is easy for consumers to misunderstand structure or function claims. For example, many consumers believe that a statement such as "helps maintain vision acuity" means the product has been proven to prevent vision loss, or that a statement such as "helps maintain a healthy prostate gland" means the product has been proven to prevent or remove diseases like prostate cancer. Do not assume that because a product claims to support or promote healthy body function that it prevents or reduces the risk of any disease, including cancer. Products that are proven to have a significant effect on any disease are considered drugs by the FDA and are strictly regulated as such. Guidelines for choosing dietary supplements safely
How to report serious adverse reactions If you or someone in your family suffers serious harm or illness as a result of supplement use, first call your doctor or other health care provider. After you have been treated, you or your doctor can report the adverse reaction to the FDA by calling 1-800-FDA-1088. Or you can go to the FDA's MedWatch Web site at www.fda.gov/medwatch/report/consumer/consumer.htm. The FDA considers an adverse event serious if it causes any of these:
When you talk to the FDA, you will need to tell them:
Along with the above required information, you will be asked about the age, weight, and sex of the person who had the problem. The FDA staff will ask when and how much of the supplement was taken, and for how long. They will want to know where and when the product was purchased, lot number, and expiration date if available. This information is generally not required, but if you can get it, it can greatly help them follow up on the problem. After you make a report to the FDA, you should notify the manufacturer of the product (listed on the label) and the store, seller, or Internet vendor where you bought the product. Be aware Know the ingredients in herbal medicines and dietary supplements you take. To help protect consumers, the FDA recommends that people using these products consider these suggestions:
Additional Resources More Information from Your American Cancer Society We have selected some related information that may also be helpful to you. These materials may be ordered from our toll-free number, 1-800-227-2345. Along with the above, information on many different types of complementary and alternative treatments are available at no cost to you from the American Cancer Society. You can find them on our Web site or request them from our toll-free number as noted above. Book The following book is available from the American Cancer Society. Call us to ask about costs or to place your order. National organizations and Web sites* Along with the American Cancer Society, other sources of information and support include: National
Institutes of Health Office of Dietary Supplements U.S. Food and
Drug Administration U.S. Department
of Agriculture, Food and Nutrition Information Center Center for Food
Safety and Applied Nutrition (CFSAN) Memorial Sloan
Kettering Cancer Center
About Herbs and Botanicals MedWatch U.S.
Pharmacopeia (USP) National Council
Against Health Fraud *Inclusion on this list does not imply endorsement by the American Cancer Society. No matter who you are, we can help. Contact us anytime, day or night, for information and support. Call us at 1-800-227-2345 or visit www.cancer.org. References Kurtzweil P. An FDA Guide to Dietary Supplements. FDA Consumer; January 1999. Accessed at: www.cfsan.fda.gov/~dms/fdsupp.html on May 29, 2009. Bronstein AC, Spyker LR Jr, Green JL, et al. 2007 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 25th Annual Report. Online Publication Date: 01 December 2008. Accessed at: www.aapcc.org/DNN/Portals/0/NPDS%20reports/2008%20AAPCC%20Annual%20Report.pdf on May 29, 2009. Office of Dietary Supplements, National Institutes of Health. Background Information. Accessed at: http://dietary-supplements.info.nih.gov/Health_Information/Health_Information.aspx on May 29, 2009. U.S. Department of Health and Human Services, Office of the Inspector General. Adverse Event Reporting For Dietary Supplements: An Inadequate Safety Valve. April 2001. Accessed at: http://oig.hhs.gov/oei/reports/oei-01-00-00180.pdf on May 29, 2009. U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition. Dietary Supplement Current Good Manufacturing Practices (CGMPs) and Interim Final Rule (IFR) Facts. June 22, 2007. Accessed at: www.cfsan.fda.gov/~dms/dscgmps6.html on May 29, 2009. U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition. Dietary Supplement Health and Education Act of 1994. December 1, 1995. Accessed at: www.cfsan.fda.gov/~dms/dietsupp.html on May 29, 2009. U.S. Food and Drug Administration. Dietary Supplements. Overview. Accessed at: www.cfsan.fda.gov/~dms/supplmnt.html on May 29, 2009. U.S. Food and Drug Administration, FDA 101: Dietary Supplements. Accessed at www.fda.gov/consumer/updates/supplements080408.html on May 29, 2009. Last Medical Review: 06/11/2009 |