Should I Take Dietary Supplements?


When diagnosed with cancer, you are eager to do whatever it takes to beat your disease. Part of that eagerness may be to use dietary supplements, such as vitamins; minerals; or herbal, botanical, enzyme or amino acid products and liquids. Not all supplements are safe or effective for all cancer survivors. Yet, some cancer centers report that 25 to 77 percent of patients take dietary supplements outside of their treatment plan developed by their healthcare team. Is this the right thing to do?

Here are three questions you should ask before taking dietary supplements:

1. Why are you taking the dietary supplement?

Most people are motivated to use supplements to manage side effects of cancer, to cope with side effects from treatment, or to prevent new cancer growth. Or, perhaps a friend or family member suggested you use a specific supplement after reading phenomenal claims online or in popular magazines. Since dietary supplements are readily available at grocery and specialty stores, taking them is a quick habit many are tempted to adopt.

However, the use of dietary supplements during cancer treatment comes with risks. If it sounds too good to be true, like a quick fix to cure cancer, it probably isn’t true. If a miracle cure is your goal, don’t use dietary supplements. Using dietary supplements without approval from your healthcare team may actually interfere with treatment instead of helping. For example, some studies report antioxidants supplements may protect tumor cells thus reducing the effectiveness of cancer treatments. Before you panic, the Oncology Nutrition Dietetic Practice Group says there is no research to suggest that antioxidant-rich whole foods or drinks must be avoided during cancer therapy. Be sure to consult with your healthcare team. Additionally, the amount of antioxidants in regular foods is unlikely to conflict with treatment.

Tip: Supplements are not a cure for cancer.

2. What are the other risks of taking the dietary supplement?

Dietary supplements are not strictly inspected and evaluated like other medications on the market. Instead, they are considered to be a “food” and are not subject to the rigorous inspections and testing the Food and Drug Administration (FDA) requires for prescription and over-the-counter drugs. Unlike drug products, FDA does not “approve” dietary supplements for safety or effectiveness before the supplements reaches the consumer. The FDA’s does regulate label claims for supplements, which must include the disclaimer “not intended to diagnose, treat, cure or prevent any disease.” Also, the supplement in the bottle may not always be free of impurities or additives to which you may be sensitive.

Tip: Look for dietary supplements that have been independently tested and certified by a non-profit group such as USP® or NSF®. A seal from one of these independent groups helps you know that the product contains what the labels say it contains without added contaminants.

3. How will the dietary supplement interact with your cancer treatments?

Interaction between supplements and cancer treatments is complicated. Some scientists have devoted their entire careers to studying these interactions. To be safe, always ask your healthcare team before taking any dietary supplement. Only use scientific, evidence-based resources for your nutrition information. As one example, the Memorial Sloan Kettering Cancer Center has a detailed supplement website. Use food first to obtain the nutrition you need during your cancer treatment plan. The food that carries the nutrients may do just as much to affect good health as the nutrient itself.

Tip: As for all food and fitness choices, dietary supplements are to be considered on an individual basis for each cancer survivor along with his or her healthcare team.

For more information about cancer and dietary supplements, check out Memorial Sloan Kettering Cancer Center’s website or Oncology Nutrition.

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