- About half of Americans who take dietary supplements believe the U.S. Food and Drug Administration has approved them as safe and effective. 1
- The U.S. Food and Drug Administration does not have the authority to approve dietary supplements, but can remove them from the market if shown to be unsafe. 2
RESOURCES

Supplements and Cancer Pocket Guide
For people in treatment or survivorship, dietary supplements may: Always talk with your health-care provider and cancer team about any supplements you take. If you are interested in taking supplements, check with your health-care team first. Supplements can be part of an integrative health plan that includes a nutritious diet, exercise, rest, social support, and other healing practices. So far, no supplement is proven effective as the sole treatment for any cancer or as a cure. If you or a loved one has cancer, you may have considered taking dietary supplements, are already doing so, or are wondering if you should. Between 60 and 80 percent of people with cancer take supplements before, during, or after their treatment. 3 Reasons for taking supplements include: Experts agree that in general, a holistic approach to diet, exercise, rest, and stress relief is the best way to improve health and potential outcomes, including in those with cancer. 3 “It’s best to get the nutrients you need from food,” says Donald Abrams, MD, an integrative oncologist at the UCSF Osher Center for Integrative Medicine. “However, as you age or when you have certain conditions, you may consider taking supplements.” An integrative approach to cancer treatment can include supplements when conventional treatments do not work well. Jeffrey White, MD, who directs the Office of Cancer Complementary and Alternative Medicine of the National Cancer Institute, says, “People seek dietary supplementation for fatigue and other issues, including sleep problems, low energy, and chemotherapy side effects such as nausea, vomiting, and neuropathy.” Simply put, supplements are anything you take to boost your body’s level of vitamins, minerals, hormones, or other nutrients. You might hear them called dietary supplements because they are intended to supplement, or add to, the nutrients you get from food and drink. 3 Supplements come in many forms, including tablets, capsules, gummies, liquids (including teas), and powders. Supplements are very popular. One study showed that more than 80 percent of adults in the United States take supplements. But only 24 percent take them because tests showed they were lacking in a certain vitamin, mineral, or other nutrient. 5 In other words, many people are taking supplements they may not need.
“What can it hurt?” you might think. After all, getting the vitamins, minerals, and other nutrients you need must be especially important when you have cancer. However, there are important reasons to talk with your cancer care team about supplements. “It’s incredibly important to stay honest and open about what you’re interested in, taking now, or want to try,” says Dr. White. “A lot of people are concerned about expressing things to their doctor. Some physicians are not as open to discussion as others, so this can be challenging, but I always recommend keeping the information exchange open on both sides.” Ways to bring up supplements with your provider include asking: If you already take supplements A Harris poll of more than 2,000 U.S. adults found that more than one-third “didn’t think their health care provider was interested” in whether they took supplements or not. 1 In fact, they are. To start the conversation, you might share something like I take ________________ and ___________________ for my health (e.g., calcium for bone health and vitamins for my eyesight). I also drink __________________________ tea (e.g., echinacea) Enough scientific evidence exists for some dietary supplements to recommend taking them for specific symptoms and side effects, provided there are not specific reasons you should not be taking them. Talk with your oncologist or other health-care provider before trying any of these. They may recommend a specific dose or formula. *Please note that many of the comments in this column are not derived from results of clinical trials. Consult your doctor if you are taking any of these or other supplements. Supplements contain powerful substances, including harmful ones. They also come in and out of vogue, often touted online by non-medical websites. “Vitamin C is something many people are interested in and consume,” says Dr. White. “Nowadays, it seems to be mostly high dose IV vitamin C as opposed to pills. That’s not really a dietary supplement—that is more like a drug.” “Social media has a big impact,” Dr. Abrams says. “Someone goes online and says, ‘This cured my cancer.’ Even laetrile, which was debunked in the 1960s, is back as ‘apricot pits’ or ‘vitamin B17.’” How supplements can affect you Some supplements can make your skin more sensitive. This can lead to severe skin reactions during radiation therapy. “Foods with antioxidant properties are fine,” Dr. Abrams says. “People ask me, ‘Can I eat blueberries? They contain antioxidants.’ The answer is yes, because blueberries do not contain such large amounts that they will interfere with chemotherapy, and they contain many other health-building compounds.” Are supplements effective at destroying cancer cells or shrinking tumors? Not that we know, according to Dr. Abrams. “For the most part, that idea is more wishful thinking than based in evidence. With many supplements, we simply do not have a body of evidence from placebo-controlled trials.” Dr. White offers this advice: “If you hear that a supplement kills cancer cells, ask, ‘Did this happen in a petri dish? Did it happen in laboratory animals? Where are the studies showing that it works in humans?” “I see many patients extrapolating from what happens in test tubes and animals to what happens in their bodies, particularly if they hope that supplements will cure their cancer,” says Dr. Abrams. “But the human body is more complex than cells in a laboratory dish.” How to evaluate supplements When considering any supplement, Dr. White says, “First ask, ‘What is the scientific evidence?’ If it is all anecdotal—personal stories—you don’t have much.” Ask your oncologist if studies have shown the supplement or product is effective for your concern. Nurses and pharmacists can also help you find reliable information. Questions to askFast Facts
SUMMARY
Dietary supplements and cancer
What are supplements?
Are supplements harmless?
How to talk with your health-care provider
Supplements for specific symptoms
Free and Low-Cost Integrative Health Resources
Supplement
Why try it?*
Things to watch out for
Ginger
Nausea and vomiting
Can work like a blood thinner. You may bleed too much if injured, if you have a bleeding risk, or if you take aspirin, ibuprofen, or other medicines that can cause bleeding.
Ginseng
Fatigue
Could cause a dangerously fast heartbeat and increase the risk of bleeding for people taking Coumadin® (warfarin).
Probiotic containing Lactobacillus and Bifidobacterium
Diarrhea from chemo drug 5-fluorouracil
Dr. Abrams recommends a refrigerated product for best effect.
Coenzyme Q10 (CoQ10)
Beneficial to the heart, if radiation was given in that region
Only take after radiation therapy ends.
Vitamin B12
Nerve problems (neuropathy) from B12 deficiency
Ask your health-care provider if this is important for you.
Vitamin C
Wound healing, stress relief
Discuss high-dose IV therapy with vitamin C, but avoid if said to “cure” cancer.
Zinc
Treating common cold symptoms or for symptoms related to radiation therapy (unproven)
Chronic use of zinc supplements can lead to copper deficiency and lowered blood counts.
Lion’s mane mushrooms
Neuropathy, “chemo brain”
Only take after chemotherapy ends. Consult your doctor if you have mutation of gene CDC73. Avoid mushrooms if receiving immunotherapy.
Melatonin
Sleep
Avoid high doses said to “cure” cancers, as this is not proven. Some people experience undue drowsiness or headaches with use.
Supplements and your treatment plan
Can supplements cure cancer?
Resources
References
Topics: Cancer | Herbs & Supplements
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