As an oncology dietitian, I encourage my patients to eat a balanced diet of whole unprocessed foods. To quote the author Michael Pollan, “Eat food, not too much, mostly plants.” So where do supplements fit in the treatment of a cancer patient?
The latest National Comprehensive Cancer Network (NCCN) Guidelines on Cancer Survivorship does not recommended supplements for most survivors except, when there are nutritional deficiencies, or concurrent conditions like osteoporosis or cirrhosis. Furthermore, there is little data to support using vitamins or other dietary supplements to either prevent cancer, control cancer, or prevent the reoccurrence of cancer after treatment. Taking vitamin supplements does not replace the need to maintain a healthy diet. It is better to get these nutrients straight from the source, and all efforts should be made to obtain nutrients naturally. Survivors of certain cancers are at risk for vitamin deficiencies based on their cancer treatment, and supplements should be recommended by a healthcare professional on a case-by-case basis.
The American Cancer Society (ACS) and The American Institute of Cancer Research (AICR) also review nutrition research to develop guidelines for cancer prevention and cancer survivors. The ACS guidelines on nutrition and physical activity for cancer prevention clearly state, “Can dietary supplements lower cancer risk? Present knowledge indicates no. While a diet rich in vegetables, fruits, and other plant-based foods may reduce the risk of cancer, there is little evidence that dietary supplements can reduce cancer risk.” The AICR’s guideline on supplements states, “Don’t use supplements to protect against cancer. To reduce your risk of cancer, choose a balanced diet with a variety of foods rather than taking supplements.” These guidelines do acknowledge that there are special individual situations where supplements would be appropriate, but these do not include cancer prevention, treatment, or survivorship.
So remember moderation is key, and a diet rich in fruits, vegetables, and other plant based sources is best.
Shayne Robinson RD CSO CDN is an oncology dietitian at NewYork Presbyterian Weill Cornell’s Ambulatory Care Network’s Outpatient Practice. To see a dietitian at the outpatient nutrition practice, call (212) 746-0838 (physician referral required).