11 Min Read
Last Updated: 02/02/2024
Fact Checked

Written by Michelle Whitmer | Medically Reviewed By Tejal Parekh | Edited By Walter Pacheco

Are Dietary Supplements Safe for Mesothelioma Patients?

Certain dietary supplements may be safe for mesothelioma patients. But the FDA classifies supplements as food rather than medication, making them less strictly regulated. Discuss safety concerns or possible interactions with your medication with your oncologist.

Herbs, antioxidants and natural substances have been researched in cancer care, too. Some of these products may be safe to use during mesothelioma treatment.

Talk to your doctor about lacking vitamins or minerals because of dietary restrictions or side effects of treatment. Only blood tests will determine your nutrition status and indicate any possible vitamin or mineral deficiency with certainty.

Vitamins and Cancer

Some vitamins protect cells from damage linked to cancer development. Researchers are studying other vitamins to discover potential therapeutic uses in cancer care.

Benefits and Risks of Vitamin Supplements

Vitamins can sometimes negatively interact with other medications you’re taking. Some vitamins may have specific health benefits, but can have side effects for cancer patients.

  • Vitamin A: Cancer patients can consume vitamin A in carotene-rich foods. However, clinical trials of vitamin A supplements found it can increase rates of lung cancer. As well as deaths among smokers and people exposed to asbestos.
  • Vitamin D: Lung cancer patients with higher vitamin D showed reduced lung cancer risk and better outcomes.
  • Vitamin K: Studies show vitamin K2, one type of this nutrient, is linked with decreased inflammation and reduced cancer risk.

Vitamin K2 dietary supplements are safe for mesothelioma patients. There can be risks for postoperative patients and those with other underlying conditions. Vitamin K may interfere with blood thinners.

Minerals and Cancer

Researchers are studying several minerals for cancer prevention and treatment. Minerals form structure in tissues, such as calcium and phosphorus in bone. They also enable cell activities necessary for life and good health.

Magnesium, Potassium and Calcium

Magnesium, potassium and calcium are important minerals for everyone. They’re especially key for mesothelioma patients receiving the chemotherapy drug cisplatin.

Key Facts About Magnesium, Potassium and Calcium

Cisplatin can decrease blood levels of magnesium, potassium and calcium to dangerously low levels. Your doctor will check your blood to track these and other important minerals during treatment. Some people need to supplement them during chemotherapy.

  • Magnesium has strong laxative effects and may cause loose stools.
  • To minimize the risk of loose stools, take the recommended dietary allowance for magnesium — 420 mg per day for men and 320 mg for women — in several smaller doses throughout the day.
  • Powdered magnesium or supplements that require four or five pills to reach the RDA work well for this.

A combination magnesium-calcium supplement also can decrease the laxative effects of magnesium.


Selenium bolsters the body’s own antioxidant systems. For this reason, it has been promoted to reduce cancer risk. However, the research doesn’t support this approach.

Key Facts About Selenium and Cancer

Multiple studies show selenium supplements are beneficial only to people who are deficient in the mineral.

  • Supplemental selenium may increase cancer and heart disease risk in people who are not deficient.
  • In some cell and animal studies, mesothelioma tumors grow more aggressively when extra selenium is supplied.
  • Selenium in dietary supplements is inorganic, which is different from the organic form of the nutrient found naturally in food.
  • If you want a safer way to get more selenium, try one Brazil nut per day. A single nut provides 110% of the recommended dietary allowance in a natural, easily absorbable form.

Based on available evidence, people at risk of mesothelioma should avoid selenium supplements. Those undergoing treatment should avoid it too.

Herbs, Spices and Cancer

People often recommend herbs and other plant substances as dietary supplements for cancer. Some of these products are safe during mesothelioma treatment, but others should be avoided.

dietary supplements moringa tree, essiac tea, and flax seeds

Moringa Tree

Moringa tree leaves are used in cooking in India. They can be powdered and taken as a dietary supplement, and moringa extracts are also used to supplement diet.

  • Studies in cancer cells and animal models suggest moringa has anti-cancer activity, but no studies in humans have proven this effect.
  • There are no studies on whether moringa is a good or bad dietary supplement for mesothelioma.

Talk to your mesothelioma specialist if you are considering trying moringa supplements.

Essiac Tea

Essiac tea was first promoted as a cancer therapy in Canada in the early 20th century. The product also is marketed under the name Flor-Essence.

  • According to a 2018 report from the National Institutes of Health, Essiac tea contains substances with antioxidant, anti-inflammatory and anti-cancer activities.
  • There is no controlled data from human studies to suggest the product is effective in the treatment of people with cancer.

Discuss the safety of Essiac tea with your doctor.


Ground flaxseeds are considered food and are safe for most people to consume. A daily intake of one to two tablespoons is a common recommendation.

  • Animal studies suggest flaxseeds and lignans, which are substances found in seeds, protect against asbestos-related inflammation and cell damage.
  • Flax can have strong laxative effects, so avoid them if you have loose stools or diarrhea because of your cancer treatment.
  • Do not take flaxseeds if you have an intestinal blockage or have been told to follow a low-residue or low-fiber diet.

Flax is now commonly found in breakfast cereals, crackers, energy or protein bars and even pastas. Flax milk is also a popular dairy alternative. Discuss adding flax to your diet with your doctor or nutritionist.

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Antioxidants, Natural Substances and Cancer

Some dietary supplements cancer patients take aren’t vitamins, minerals or herbs. Instead, they are simply natural substances found in plants or animals.

Beta Glucan

Beta glucans are a type of soluble fiber in whole grains such as oats, barley, wheat and rye. Reishi, shiitake and maitake mushrooms also contain this substance.

  • Researchers are studying beta glucans for their ability to bolster immune function, protect against bacterial infections and support the function of immune cells called natural killer cells.
  • This component of immunity plays an important role in fighting cancer.

Beta glucan-rich foods are considered safe for mesothelioma patients. Check with your doctor before trying beta glucan supplements, however.

Beta Carotene

Beta carotene is the natural, orange pigment in sweet potatoes, carrots, mangos and other fruits and vegetables.

  • Consuming beta carotene from food is associated with reduced risk of cancer among smokers and people with a history of asbestos exposure.
  • Beta carotene supplements, however, are proven to increase the risk of lung cancer and death in these same high-risk groups.

People with a history of smoking or asbestos exposure should avoid beta carotene supplements.

Coenzyme Q10

The body naturally produces this antioxidant. It’s also obtained from foods such as beef, chicken, pork, trout, herring, sardines, soybeans, lentils and peanuts.

  • Animal studies and small, uncontrolled human trials suggest this substance may protect the heart against damage some chemotherapy drugs cause.
  • Coenzyme Q10 is a potent antioxidant, and some oncologists feel antioxidants may interfere with cancer treatments.

It’s important to tell your doctor if you plan to try this or any other dietary supplements.

Mushrooms and Mushroom Extracts

Mushrooms have a long history of use in traditional Chinese and Japanese medicine. Certain mushrooms may improve immune function and lessen side effects of cancer therapy.

  • One of the most popular cancer-fighting mushrooms is Coriolus versicolor, commonly called turkey tail. Researchers have studied turkey tail mushroom and its extract PSK in gastric, breast, colorectal and lung cancers. They have not been studied in mesothelioma patients.
  • A systematic review published in Integrative Cancer Therapies concluded, “PSK may improve immune function, reduce tumor-associated symptoms, and extend survival in lung cancer patients.”
  • A 2019 National Cancer Institute Cancer Information Summary indicates PSK has been used as adjuvant therapy in thousands of cancer patients since the mid-1970s. It has been used in people for a long time in Japan and few side effects have been reported.

Still, as with all over-the-counter products, ask your doctor before trying it for yourself.

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Side Effects of Dietary Supplements

Many of these are safe for mesothelioma patients. Some dietary supplements have side effects or interfere with your cancer treatment.

  • Grapefruit: Eating grapefruit or drinking grapefruit juice can block an enzyme in the intestine that helps metabolize certain mesothelioma chemotherapy drugs, including vincristine and paclitaxel.
  • Probiotics: Probiotics may lead to infections in cancer patients with poor immunity caused by treatment. These supplements also may reduce effectiveness of immunotherapy.
  • Iron: Excess iron may lead to nausea and vomiting and can damage the heart, liver, lungs, kidneys and other organs.
  • Vitamin C: This vitamin may protect cells from chemotherapy and radiation therapy in ways that reduce the effectiveness of treatment. Studies suggest oral vitamin C may be more problematic than IV vitamin C, because delivering the vitamin right into the bloodstream makes it act more like a drug than an antioxidant.
  • Vitamin A: Excessive amounts of vitamin A cause headaches, reduced bone strength and bone fractures, liver damage and birth defects.
  • Vitamin K: This vitamin interferes with blood thinners.

If you decide to try dietary supplements, discuss each one with your mesothelioma doctor or another member of your health care team.

They consider your medication, other medical conditions you have and planned mesothelioma treatments. This assessment determines whether a dietary supplement is safe for you.

Risks of Taking Dietary Supplements

The U.S. Food and Drug Administration offers an online, nonmandatory reporting system to track dietary supplement side effects. Their data shows people are increasingly reporting cases of illness and injury associated with using supplements.

  • Reports of dietary supplement-related adverse events nearly tripled from 1,009 to 2,844 between 2010 and 2012.
  • A New England Journal of Medicine study in 2015 attributed approximately 23,000 emergency room visits per year to adverse reactions to dietary supplements.

A 2018 JAMA Forum Commentary noted dietary supplements are a $30 billion a year business. It called for more research on safety, benefits and harms of dietary supplements.

Risks of taking dietary supplements may include:

  • Reduced effectiveness of chemotherapy, radiation therapy and other anti-cancer drugs
  • Increased effectiveness of chemotherapy to the point of toxicity
  • Increased skin sensitivity, which may harm radiation therapy patients
  • Liver damage from certain herbs such as kava root and comfrey

Limited oversight leaves room for contamination with toxic chemicals. Consumers may also purchase and consume supplements that contain unlisted ingredients.

Common Misconceptions About Supplements

There are some common misconceptions around supplements and natural products. Natural is not always better or safer.

Natural Is Better, Safer

The term “all natural” has become a buzzword in the health industry. Because some people have had adverse reactions to lab- or factory-made chemicals, “all natural” can feel safer.

While this feeling is understandable, it should be weighed with the knowledge that many natural substances can be harmful, too. For example, arsenic and asbestos are naturally occurring and toxic. Plants are natural, yet many are poisonous, including oleander and tobacco.

Taking a Megadose of Vitamins Is Safe

In the 1990s it became popular to megadose, or take large amounts of certain supplements, such as vitamins C and E.

Some people believed large doses of vitamin C could cure the common cold or treat cancer. Research does not indicate it can cure any cancer. In fact, too much vitamin C can block your body’s ability to absorb copper, an essential trace mineral involved in making red blood cells.

It Can’t Hurt to Take Supplements with My Medicine

Unfortunately, some supplements have negative interactions with prescription medication and cancer treatment. It isn’t safe to assume any herb, vitamin or mineral won’t interact with your medication or cancer treatment just because it is natural or seems harmless.

Additionally, few drug companies or supplement producers research potential interactions.

A 2022 study published in the Journal of Cancer Research and Clinical Oncology evaluated the risk of drug interactions among cancer patients taking dietary supplements, herbs and other compounds. Researchers found 61.7% of participants were at risk for a major drug interaction.

The FDA Won’t Allow It on the Market if It Isn’t Safe

Dietary supplements are regulated differently than prescription drugs and cancer treatments. Supplements do not undergo years of testing before reaching the market.

Consult Your Doctor

Gather information about these natural products from a trustworthy source. The National Institutes of Health Office of Dietary Supplements is a good resource. Share this information with your doctor, so they can give you the best advice possible.

Tell your oncologist if you took any supplements before your diagnosis, too.

After treatment, your oncologist may give you approval to take certain supplements. Don’t start supplements without talking to them first.

Your doctor will know how long it may take for your body to process cancer treatment. Knowing this can help you avoid a potential nutrient-drug interaction.

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