A normal, healthy body produced between 100,000 and a million cancerous cells per day. The immune system can kill about 10 million per day. Thus cancers grow when either you make more than 10 million per day (for example by smoking) or your immune system is less active than it needs to be.
One way in which a fasting diet may help cancer patients is by triggering the immune system. The immune system is designed to target and destroy pathogens in the body, like viruses. However, it seems to be less able to find, target, and kill the body’s own abnormal cells, like cancer cells. A lot of new cancer treatments are being developed to stimulate the immune system to do this, but new research is finding that a simple fasting diet could also do it.
When you eat, about one-third of your immune system is busy “fighting food” and cannot be deployed against your cancer cells. Thus during fasting, you can “mop up” the bad cells.
One recent study from the University of Southern California was conducted using lab mice and found that when the mice received chemotherapy and a fasted diet, the immune system was better able to target and kill breast cancer cells and skin cancer cells. The mice produced more immune system cells when on the fasted diet, including the B cells and T cells that actively target and kill tumor cells. Another discovery was that cells that normally protect tumors called T regulatory cells were kept out of the tumors. This may have helped chemotherapy drugs work better.
The same researchers also conducted a pilot study with human cancer patients, mainly to determine if fasting diets with chemotherapy would be safe. Alternate Day Fasting and Daily Intermittent Fasting were found to be safe for cancer patients under the supervision of doctors. All of these findings indicate that fasting or a fasting-mimicked diet along with chemotherapy could be used to slow tumor growth in cancer patients.
Fasting appears to protect normal cells from chemotherapy’s toxic effects by rerouting energy from growing and reproducing to internal maintenance. But cancer cells do not undergo this switch to self-repair and so continue to be susceptible to drug-induced damage making for what the researchers call a differential stress resistance. Fasting then should enhance the power of chemotherapies without having to resort to “the more typical strategy of increasing the toxicity of drugs.”