Nutrition Trends in Cancer: National Cancer Institute 2023

KEY POINTS

• Some cancer patients try special diets to improve their prognosis.
• Some cancer patients may take dietary supplements.

Some cancer patients try special diets to improve their prognosis.

Cancer patients may try special diets to make their treatment work better, prevent side effects from treatment, or to treat the cancer itself. However, for most of these special diets, there is no evidence that shows they work.

Vegetarian or vegan diet

It is not known if following a vegetarian or vegan diet can help side effects from cancer treatment or the patient's prognosis. If the patient already follows a vegetarian or vegan diet, there is no evidence that shows they should switch to a different diet.

Macrobiotic diet

A macrobiotic diet is a high-carbohydrate, low-fat, plant-based diet. No studies have shown that this diet will help cancer patients.

Ketogenic diet

A ketogenic diet limits carbohydrates and increases fat intake. The purpose of the diet is to decrease the amount of glucose (sugar) the tumor cells can use to grow and reproduce. It is a hard diet to follow because exact amounts of fats, carbohydrates and proteins are needed. However, the diet is safe.

Several clinical trials are recruiting glioblastoma patients to study whether a ketogenic diet affects glioblastoma tumor activity. Patients with glioblastoma who want to start a ketogenic diet should talk to their doctor and work with a registered dietitian. However, it is not yet known how the diet will affect the tumor or its symptoms.

Similarly, a study comparing the ketogenic diet to a high-fiber, low fat diet in women with ovarian cancer or endometrial cancer found that the ketogenic diet was safe and acceptable. There is not enough evidence to know how the ketogenic diet will affect ovarian or endometrial tumors or their symptoms.

Some cancer patients may take dietary supplements.

A dietary supplement is a product that is added to the diet. It is usually taken by mouth, and usually has one or more dietary ingredients. Cancer patients may take dietary supplements to improve their symptoms or treat their cancer.

Vitamin C

Vitamin C is a nutrient that the body needs in small amounts to function and stay healthy. It helps fight infection, heal wounds, and keep tissues healthy. Vitamin C is found in fruits and vegetables. It can also be taken as a dietary supplement. For more information about the use of intravenous vitamin C as treatment for people with cancer, see Intravenous Vitamin C.

Probiotics

Probiotics are live microorganisms used as dietary supplements to help with digestion and normal bowel function. They may also help keep the gastrointestinal tract healthy.

Studies have shown that taking probiotics during radiation therapy and chemotherapy can help prevent diarrhea caused by those treatments. This is true for patients who receive radiation therapy to the abdomen. Cancer patients who are receiving radiation therapy to the abdomen or chemotherapy that is known to cause diarrhea may be helped by probiotics. Similarly, studies are looking at potential benefits of taking probiotics for cancer patients who are receiving immunotherapy.

Melatonin

Melatonin is a hormone made by the pineal gland (tiny organ near the center of the brain). Melatonin helps control the body’s sleep cycle. It can also be made in a laboratory and taken as a dietary supplement.

Several small studies have shown that taking a melatonin supplement with chemotherapy and/or radiation therapy for treatment of solid tumors may be helpful. It may help reduce side effects of treatment. Melatonin does not appear to have side effects.

Oral glutamine

Oral glutamine is an amino acid that is being studied for the treatment of diarrhea and mucositis (inflammation of the lining of the digestive system, often seen as mouth sores) caused by chemotherapy or radiation therapy. Oral glutamine may help prevent mucositis or make it less severe.

Cancer patients who are receiving radiation therapy to the abdomen may benefit from oral glutamine. Oral glutamine may reduce the severity of diarrhea. This can help the patients continue with their treatment plan.

Source: https://www.cancer.gov/about-cancer/treatment/side-effects/appetite-loss/nutrition-pdq#_667