- Diet & Weight Loss
Can Short-Term Fasting make Chemotherapy Safer and More Effective in Curing Cancer?
There is some exciting research suggesting that short-term fasting during chemotherapy may not only reduce side effects, but may make the treatment more effective in destroying cancer cells. Initial testing on mice as well as informal results with humans have yielded such positive results that clinical trials with humans are underway as I write this. Fasting is one of many things patients should be aware of when faced with chemotherapy, as discussed in Ten Things I Wish My Doctor Told Me About Chemotherapy.
How Does Fasting in Conjunction with Chemotherapy Protect Healthy Cells and Destroy Cancer Cells?
Chemotherapy destroys healthy cells along with cancer cells. Side effects are caused by the destruction of these healthy cells.For example, neuropathy results when healthy nerve cells are destroyed causing the sheath of the protective covering to degenerate. This results in feelings of numbness,tingling,pain, and often affects coordination and balance. This is a significant problem for many cancer patients undergoing chemotherapy.
Fasting appears to naturally slow the growth of healthy cells by causing the body to send instructions to cells to slow down and consume less energy. In effect, normal cells in the body go into "maintenance mode", much like an animal in hibernation. Cancerous cells typically ignore instructions from the body (which is why they are cancerous), and therefore are not affected by fasting. Thus, fasting during chemotherapy reduces the absorption of harmful drugs by the healthy cells by slowing down their growth, while the cancer cells continue to grow unabated. This has the obvious effect of reducing the negative side-effects without impacting the effectiveness of the treatment. If the healthy cells are protected higher and more frequent doses of chemotherapy can be given to patients resulting in a more effective treatment for some patients.Thus, advanced or more aggressive cancers may be safely treated without increasing the risk of side-effects of the chemotherapy.
Studies Testing this Theory
1. Study with mice: In 2008 Valter Longo conducted a study on mice to test this theory. The results were published in the science journal Science Translational Medicine. One of the many interesting results was that five of the eight cancers tested responded to fasting alone. Normal cells in the body obey instructions to reduce growth when in a fasting state. However, cancer cells do not recognize the instructions, and continue to attempt to grow and divide even without the required nutrients in the blood - in some cases resulting in self-destruction.
How to Fast During Chemotherapy
If the oncologist agrees, the patient can fast for 3 days before and 1 day after chemo. Depending on what type of chemo is being administered and at what intervals this could change. Patients should avoid re-feeding (resuming their regular diet) until the chemotherapy is below toxic blood levels (usually 24-48 hours after administration). Although we have rarely seen negative side effects caused by fasting (high liver toxicity markers in 1 patient fasting and receiving a chemo cocktail) there are some potential risks so keep that in mind. For example, an early re-feeding immediately after the chemo could cause liver damage, because of the combination of hepatotoxic drugs with the proliferation of the liver caused by fasting. For this reason is important to have a minimum of 24 hours after the chemotherapy is administered. Also, several patients have fainted while taking hot showers after several days of fasting probably because of the major reduction in blood pressure and glucose levels after day 1 of fasting. The patient should not drive or operate machinery or should be accompanied by someone during the fasting period. Most people can drive while they are fasting but for a few this could be a problem so unless you know fasting does not affet your ability to drive, don’t drive. Starting 24 hours after the chemotherapy, the patient should only eat rice, pasta or a similar source of carbohydrates + soups + fruit juices for a period of 24 hours. Then, a normal diet can be resumed, paying particular attention to nourishment (vitamins, minerals, proteins, essential fats). The patient should also try to return to within 2-3% of their body weight before doing another fasting cycle. Obese patients should consult their doctors on whether some of the weight loss caused by fasting is advisable and whether they should try to remain at the lower body weight. Diabetic patients should not undergo fasting unless this is approved by their diabetologist. Subjects on hypertension medication should also talk to their doctor about the blood pressure drop caused by fasting and the risk of combining fasting with medications. Until clinical trials are completed fasting will remain an experimental procedure and should only be considered with the approval of the oncologist and when other viable options are not available or are known to be ineffective.
Between fasting cycles, a low sugar accompanied by a mostly plant based 0.8 grams/kg of body weight/day protein intake diet (approximately 10% calories from proteins) is recommended but a registered dietician should be consulted to avoid malnourishment and unwanted weight loss.
However, the combination of fasting and chemotherapy was either more or much more effective than the chemotherapy or fasting alone. In all cases there was a slowed tumor growth and/or a reduction of the spread of cancer to other organs. For example, multiple cycles of fasting combined with chemotherapy were used to treat a very aggressive form of cancer that is common in children. The combination of fasting and chemotherapy cured 20% of the mice although the cancer had spread. 40% of the mice were cured in cases where the cancer had not spread. The interesting thing about these results were that none of the mice survived that were treated with chemotherapy alone. (Longo, V. 2012. Fasting Cycles Retard Growth of Tumors and Sensitize a Range of Cancer Cell Types to Chemotherapy. Science Translational Medicine.)
2.Small Study with Humans:
In 2010 a case report published in the Journal Aging involved ten individuals going through treatment for breast, ovarian, lung, and several other types of cancer, The patients fasted for periods ranging from 48-140 hours before, and 5-56 hours following chemotherapy. None of the patients had advserse effects from the fasting (other than the expected hunger and lightheadedness). Six of the patients went through therapy both with and without fasting for different cycles. Uniformly, the patients reported fewer to no negative side effects of the chemo while fasting. For example, one breast cancer patient felt so bad after second and third treatments (without fasting), that she had to stop working. When she resumed fasting for her fourth cycle, she reported feeling much better, even though each cycle of treatment typically causes the effects to get worse due to cumulative toxicity. This response was typical for all the patients undergoing the study. (Longo,V. 2010. Fasting and Cancer Treatment in Humans: A Case Series Report. Aging)
3. Self-Reported Results
Many people on forums expressed positive results with the fasting. For example. a man in his 80's said he had been so tired during his first sessions that he could barely get out of bed. When he tried fasting, he felt so much better that he was able to play an entire game of golf and went from being a very cranky person to feeling much happier. One woman going through breast cancer fasted for the first two treatments but not for the third. After the third one she had headaches. much more fatigue, and felt nauseous. She immediately resumed fasting, and felt much better for the remainder of her treament.
If you are interested in participating in one of the clinical trials regarding the results of fasting combined with chemotherapy or want further information on this topic contact:
1. Mayo Clinic
2. Usc Norris Comprehensive Cancer Clinic
Current Clinical Trials
Several clinical trial are currently being performed at multiple cancer centers and research hospitals. Particularly notable is the Mayo Clinic trial running from 2010-2015. Another important study is now being done at the USC Norris Comprehensive Cancer Center. The treatments being studied are for breast, urinary tract, and ovarian cancer. An initial phase has been completed, although it was merely to verify that patients can tolerate a 3-day short-term fast of 2 days before and 1 day after treatment.
Dangers of Fasting During Chemotherapy
In certain cases there may be risks associated with fasting during chemotherapy, so always check with your doctor before making your own decision. For example, fasting can be dangerous to patients with diabetes, who have experienced significant weight loss due to illness, are on medication that must be taken with food, or are at risk of low blood pressure.
My Personal Experience
While I was going through chemotherapy, the only resources I could find were the study with mice, the informal subjective 10-patient human study, and self-reported results on forums. Furthermore, I didn't find any of this information until after my first round of chemotherapy. When I asked my oncologist for information about the study she brushed me off and told me to contact the nutrition counseling center - although she did acknowledge that she didn't see any dangers of fasting (other than predicting even more discomfort than chemo normally causes) . The center responded as if I was crazy, and simply told me to drink a lot of milkshakes and other high-calorie foods to maintain my weight - in spite of the fact that I maintained a healthy weight through my entire treatment. Based upon the available information, and since I did not fall into any of the high-risk categories for fasting, I made the decision to try it.
During my treatment, my oncologist did not ask about my diet at any point. Furthermore, I did not have any significant weight loss due to the anti-nausea drugs and steroids (rather, they made me eat like a football player), and I had frequent blood tests. I fasted 2-3 days before,the day of chemotherapy, and at least 24 hours after. I'm not a person that had ever fasted before, and cannot bear it during my normal life - but I was so desperate to minimize any permanent damage (such as neuropathy) that I was able to force myself through it. There are many people that took the same drugs who are now using a cane or a wheelchair for life due to permanent neuropathy. In fact, since it was so common, my oncologist routinely asked how "my neuropathy" was - despite the fact that I kept telling her I didn't have it at all!
Since I discovered this study only after the first round of chemotherapy, I initially experienced mouth sores, exhaustion, and extreme weakness such that I could barely walk the next morning because my legs were shaking and so unsteady. After I began fasting during later sessions, I didn't experience mouth sores, generally had less fatigue, and never got a trace of neuropathy. I did experience hair loss and some fatigue - but no other side effects. In hindsight I think my emotional state may have strongly contributed to my fatigue because I was never so tired that I needed a nap.
The current studies need to address whether fasting does in fact reduce side effects in humans, how long an individual needs to fast, and what types of cancer fasting is effective for. It is also vital to prove that fasting does not negatively affect the effectiveness of the treatment, so that people will feel more free to try it even in the absence of proven positive results. Also, some research is being done to develop drugs that will put cells into a "fasting-like maintenance mode", so people who otherwise could not tolerate fasting could still benefit from the protective response of the cells. It will be very exciting to follow these studies and I will update this article when results become available.