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Fasting During Treatment

Ask the Nutritionist

Q: Many chronic lymphocytic leukemia (CLL) patients are wondering if the "immune system rebooting fasting mimicking diet" in all the papers last week from USC, Dr. Loomis is good or bad for CLL. It stimulates stem cells to reboot and make more new neutrophils and Leukocytes. The question is: does it stimulate more malignant B cells?

Ronald R. Campbell, MD, New Brunswick, Maine, September 2015

A: Current research around fasting and its affect on the human body is limited. The article you refer to, "Prolonged Fasting Reduces IGF-1/PKA to Promote Hematopoietic-Stem-Cell-Based Regeneration and Reverse Immunosuppression," published in Cell Stem Cell discussed the effect of prolonged fasting (48-120 hours or 2-5 days) on mice. The lack of human studies is concerning, and any clinical recommendations regarding prolonged fasting could not be made until sufficient human research and clinical trials have been conducted.

Prolonged periods of fasting, as discussed in the article, and the lack of nutrition are extremely concerning for patients receiving chemotherapy or other treatment who are already at an increased nutritional risk. Such lengths of time without nutrition could lead to a loss in lean body mass and a decline in overall. Furthermore, a lack of nutrition could exacerbate the side effects of treatment, and may lengthen recovery time or lead to poor health outcomes. We would not recommend prolonged fasting for patients receiving treatment, or even the general population at this time.

To promote overall health, it is best to eat a variety of fruits, vegetables, whole grains, lean proteins, and healthy fats.

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