Diets, Supplements, and Cancer – NCI

Many people want to know if they can fight cancer by eating certain foods or taking vitamins or supplements. But there is no proof that any nutrition trend, food, vitamin, mineral, dietary supplement, herb, or combination of these can slow cancer, cure it, or keep it from coming back. Tell your doctor, nurse, or dietitian about any vitamin, mineral, dietary supplements, or medicinal herbs you are already taking or plan to take. Also, talk with them before you decide to go on a diet.

Though there is no proof that these diet types or trends can slow, cure, or keep cancer from coming back, some you may hear about include:

Dietary supplements and cancer

A dietary supplement is a product that is added to the diet. It is usually taken by mouth as a pill, capsule, or powder. Some people with cancer think about trying dietary supplements to improve their symptoms or treat their cancer. But some dietary supplements may be dangerous and change how your cancer treatment works.

Even though FDA does not regulate dietary supplements, there are product manufacturing and labeling requirements in place that supplement companies are required to follow.

It is important to always check with your doctor before starting a dietary supplement since many will change how your treatment works. Learn more about Cancer Therapy Interactions with Foods and Dietary Supplements.

Some dietary supplements, such as vitamin C, oral glutamine, and melatonin, are being studied to help with side effects of cancer treatment. Find more information on supplements in this list of Dietary Supplement Fact Sheets from the NIH Office of Dietary Supplements.

Talking with your doctor about popular diets and supplements

While there’s no proof that popular diets and supplements can treat cancer, eating a healthy, well-balanced diet is important for your health. If you want to try a diet or supplement, talk with your doctor.

Aside from diet, you may be able to make other changes to your lifestyle that can help improve your well-being and help you cope with cancer. Learn more at Complementary and Alternative Medicine.