Some supplements may not be safe for cancer patients

Some nutritional supplements may not be safe for cancer patients.
Some supplements and naturopathic remedies may be beneficial for people with cancer. But others may make treatment less effective.

More than two-thirds of Americans use some kind of dietary supplement. While vitamins, plant-based herbal preparations and homeopathic remedies can offer benefits for some people, the story is more complex for cancer patients.

“Supplements must take into account not just the specifics of a patient’s cancer diagnosis, but other aspects of their health, including other health conditions and current medications,” says Michael Walker, ND, naturopathic provider at City of Hope® Cancer Center Chicago.

Some supplements and naturopathic remedies may be beneficial for people with cancer, Walker adds. But others may make treatment less effective. This article addresses the most important issues related to supplement safety for cancer patients, such as:

If you’re interested in learning more about the naturopathic support and other integrative care services for cancer patients, or if you want to speak with someone about your cancer treatment options, call us or chat online with a member of our team.

The benefits and drawbacks of supplements for cancer patients

Some studies have confirmed the specific benefits of certain supplements for cancer patients, for instance:

Your care team should consider your cancer diagnosis, overall health, diet, age, genetics and other factors when determining if supplements may be helpful for you.

“The biggest benefit is from nutrient supplementation that addresses a specific need,” Walker says. For instance, some cancer patients have trouble getting enough magnesium or eating enough protein. Supplements may help improve their overall health, making treatment more tolerable.

Are all-natural ingredients safe?

Some supplements that you can buy online or in a store are labeled as “all natural.” However, this doesn’t necessarily mean they are safe.

“Even some vitamins and minerals, if used inappropriately, can have serious health consequences, including excessive use of vitamin A, vitamin D and iron,” Walker explains. Sometimes, even a minor ingredient—such as black pepper in curcumin supplements—may cause issues such as abdominal pain or diarrhea.

Certain supplements may have negative effects during cancer treatment. These include:

  • Reducing the effectiveness of your cancer drugs
  • Increasing your risk of internal bleeding or liver and kidney damage
  • Damaging your central nervous system
  • Unexpected toxicity

Supplements may also impact the efficacy of some of the most common cancer treatments as outlined below.

Supplements and radiation therapy

In the case of radiation therapy, some supplements may make the skin more sensitive during treatment. Antioxidants such as vitamins A, C or E can also make radiation therapy less effective.

“This does not mean that every food and herb with antioxidant activity is bad,” Walker adds. “Some, like the plant extracts curcumin and berberine, may limit some radiation side effects and do not detract from the anti-cancer effect.”

Supplements and chemotherapy

Some supplements may also make chemotherapy less effective. A well-known example is the herb St. John’s wort. Sometimes recommended for people with depression, this herb may make the body rid itself of chemotherapy drugs before they’ve had a chance to work properly.

Another concern includes certain supplements or foods that can affect how the body processes a drug or medication. Grapefruit, for instance, can increase drug exposure in the body, risking excess toxicity. For people who experience diarrhea – a common side effect of chemotherapy – taking a supplement such as magnesium can make this side effect worse and increase fluid and nutrient loss.

Supplements and cancer surgery

Supplements with known negative effects include vitamin E, which may cause excess bleeding during surgery. Some others may affect the brain or heart during surgery or interfere with how well anesthesia works.

Evaluating supplement safety

Determining whether a supplement is safe and effective may be difficult. Supplements aren’t approved by the U.S. Food and Drug Administration (FDA) in the same way as medicines, and the list of ingredients on the label may not even be accurate.

Supplement labels by law must include this disclaimer required by the FDA: “This product is not intended to diagnose, treat, cure, or prevent any disease.”

For cancer patients, seeking expert advice is the first step to determine if a supplement may be an option, says Walker.

Questions to keep in mind when talking to your cancer care team about supplements include:

  • Does this supplement come from a reputable source?
  • Is there potential for overdosing on the supplement?
  • Are allergies, physical reactions or other side effects common?
  • Does the supplement have negative interactions with any cancer medications?

A naturopathic provider may help most patients understand which supplements may help them most.

“The principles we use in guiding patients are the same as with medicines,” Walker says. “We convey the relevant potential benefits and risks, and information on how the interventions works. Thankfully, many commonly used supplements have good safety and relatively larger therapeutic windows.”

Supplements vs. medication

Even though they may have medicinal properties, supplements are not medications. Generally speaking, supplements are divided into two categories: nutrients and herbs.

“Nutrients, like vitamin D, are different than most medications and herbs, in that they are required for one or more bodily functions,” explains Walker.

Herbs come from plants that humans already consume in food or other medicines.

“Plant parts, extracts and even individual constituents can have profound effects,” Walker says. And in many cases, “it is clear that a plant or plant part has numerous constituent chemicals with important effects.”

Because many supplements have not been fully studied, cancer patients should always discuss their concerns about supplements with their cancer care team.

“Appropriate supplementation is based on informed decision-making by a patient working directly with a practitioner with oncology-specific training and experience who is also well-versed in nutrients, botanicals and herbs,” Walker says.

If you’re interested in learning more about naturopathic support and other integrative care services for cancer patients, or if you want to speak with someone about your cancer treatment options, call us or chat online with a member of our team.