Supplements: What to Take and Avoid During Cancer Treatment

Good nutrition is important when you are going through cancer treatment. When your body has all of the nutrients it needs, you can keep up your strength, experience fewer treatment side effects, and heal more quickly.

It can be hard to get proper nutrition through diet alone, so many people living with cancer turn to nutritional supplements. There are a wide variety of possible products available — vitamins, minerals, herbs, enzymes, amino acids, and more. While some of these products may help you maintain health, others may be unhelpful or even harmful. Learning more about effective supplement use while fighting cancer can help you feel better and keep yourself safe.

Supporting your health with supplements

If you are undergoing cancer treatment, you may want to consider using supplements like:

• Ginger — This supplement is effective at reducing nausea and vomiting in people undergoing chemotherapy.
• Probiotics — Taking these microorganisms may help prevent digestive side effects, such as diarrhea, that are often seen during chemotherapy and radiation therapy treatments.
• Oral glutamine — Glutamine is an amino acid that may help relieve mouth sores caused by chemotherapy.
• Melatonin — This supplement may reduce several physical and mental side effects of cancer treatment and improve sleep.
• Vitamin E — Taking vitamin E may help prevent neuropathy, a type of nerve damage caused by chemotherapy that leads to pain or numbness in the hands and feet.
• Mistletoe extract — Several studies have found that when people with cancer take this supplement, they have fewer symptoms and side effects and sometimes even live longer.

While supplements don’t typically fight cancer directly, they can help you feel as good as possible while you’re taking cancer-fighting medications.

Supplements to avoid during cancer treatment

Some supplements cause more harm than good for people fighting cancer. In particular, certain compounds can interfere with chemotherapy or targeted therapy. The supplements may decrease the ability of the cancer drugs to fight tumors. If you’re using these cancer treatments, you may want to avoid:

• St. John’s wort
• Green tea extract
• Garlic extract
• Echinacea
• Curcumin
• Valerian root

Certain supplements can also thin your blood and increase your risk of bleeding problems during or after surgery. These include garlic, ginger, ginkgo, aloe, and vitamin E. Ask your doctor if you should stop taking any supplements before undergoing cancer surgery.

The use of antioxidants is somewhat controversial during cancer treatment. Antioxidants like vitamin C, vitamin E, and coenzyme Q10 protect cells from damage. While this is normally a good thing, it may not be helpful while fighting cancer. Chemotherapy and radiation therapy treatments work by damaging cancer cells, so taking antioxidants could protect cancer cells from dying. Some studies have found that people who use antioxidants have fewer side effects and have better outcomes. Others have shown that taking antioxidants can make your cancer more likely to come back or even increase your risk of death. If you’re interested in trying antioxidants, talk to your oncologist first.

Additionally, beware of claims that certain supplements can treat cancer, as these are often unproven. For example, some people believe that laetrile, also known as vitamin B17, has cancer-fighting effects. However, this supplement didn’t stop cancer growth in clinical studies, and high doses of laetrile can lead to cyanide poisoning.

What to be aware of when using supplements

Just because a supplement is “natural,” “herbal,” or “organic” doesn’t necessarily mean that it’s safe. Thousands of people go to the emergency room each year because of supplements. Try to buy your supplements from reliable manufacturers and don’t take higher doses than recommended on the package or by your doctor.

Additionally, understand that supplements won’t stop your cancer from returning after it’s been treated. Many people believe that taking supplements reduces their risk of developing cancer again in the future, but research has not found this to be the case. However, studies have shown that regularly eating a variety of fruits and vegetables can help prevent cancer from coming back.

The bottom line

Taking certain vitamins or supplements can boost your health and help you feel better while you are going through cancer treatment. However, you should be aware that some supplements can interfere with your treatment or have unexpected negative health effects.

If you’re not sure whether a particular supplement is safe, ask your oncologist. Always talk to your doctor before trying a new supplement, and make sure that your health care team knows the full list of vitamins, minerals, supplements, and herbs that you are taking during treatment.