Fasting Reduces Chemotherapy Side Effects

Listen to me. These starved little mice could save your life.

Recently, an article appeared in the Proceedings of the National Academy of Sciences (PNAS), a prestigious scholarly journal, about fasting and chemotherapy. The author, Dr. Valter Longo, studied mice that were denied food for two days (but had ready access to water) or had eaten normally. The two groups were then given a high dose of chemotherapy (three times the maximum allowable dose in humans.)

The fasted mice survived and experienced few side effects from the toxic levels of the chemotherapy drug.

Almost half of the mice that ate normally died from the high dose of the chemotherapy drug itself.

Though the fasting mice lost about 20% of their body weight while fasting before the chemotherapy treatment, they steadily gained the weight back in about four days after the treatment.

That’s right, the fasting mice gained weight right after chemotherapy.

The feasting mice, on the other hand, lost about 20% of their body weight following the chemotherapy treatment, from the usual effects of chemotherapy that any cancer patient can expound upon.

More Fasting, More Chemo

To further confirm their results, the scientists tried an even more stringent protocol on another strain of mice. Lab mice are notoriously inbred, and different genetic strains can produce contradictory results. Good results can be confirmed in several mouse types.

These mice were starved for 60 hours (2 1/2 days,) which is the amount of time that the researchers found to be optimal in other tests. Fasting for longer than 60 hours weakens the mice more than it helps them resist the chemotherapy and makes them die more. Then, the scientists dosed these mice with an even higher dose of the chemotherapy drug, almost four times the human maximum allowable dose.

This very high dose of the chemotherapy drug killed all the feasting mice within five days but none of the fasting mice (60 hours of fasting) in the next twenty days. The fasting mice lost 40% of their body weight before the chemotherapy treatment but gained it back within a week after the treatment with, in the words of the authors, “no visible signs of toxicity.”

Let me put it thusly: The exceedingly high dose of chemotherapy killed all the normally eating mice, but if the mice were fasting, it didn’t even make them sick.

Naked Data

Longo also repeated these results in Nude mice, a hairless strain of mice without thymus glands and thus little immune function. They are used extensively in cancer research as they have no immune system to fight the introduced cancer, and thus all the effect of cancer reduction can be attributed to the tested chemotherapy drug.

His results were essentially the same: starved Nude mice survived. Non-starved Nude mice died from the high-dose chemotherapy drug.

Starving Mice with Cancer

Longo then injected mice with virulent cancer cells, a neuroblastoma cell line, using a protocol that mimics the conditions of aggressive, metastatic pediatric cancers, which are some of the most deathly cancers.

Not only did the fasted mice survive the subsequent chemotherapy with fewer side effects, but it appeared that the cancer cells were more susceptible to the chemotherapy than normal cells. The fasted mice survived the metastatic cancer protocol almost three times as long as normally eating mice and around five times as long as untreated mice.

This suggests that the fasted state did not protect cancer cells nearly as much as normal cells were shielded from the effects of chemotherapy, thus suggesting that longer or higher-dose chemotherapy protocols might be devised with fewer side effects but better results.

Longo hypothesized about the reasons for the effect of fasting. He surmised that, as any dieter knows, fasting slows cellular metabolism in normal cells. Thus, after fasting, the normal cells in their state of semi-suspended animation took up less of the toxic chemotherapy drug and thus were less affected by it.

Cancer cells, however, are relentlessly driven by oncogenic growth factors to be fruitful and multiply, no matter what the metabolic cost. Thus, fasting did not lower the metabolic rate of cancer cells. The cancer cells, with their metabolic afterburners still lit, sucked in the chemotherapy drug and were killed by it.

It’s a great mouse study.

Clinical Trials: Starving Cancer Patients

Longo is currently enrolling lung and bladder cancer patients for a clinical trial to fast before receiving their standard chemotherapy.

The lung and bladder cancer patients in the control group (people given standard treatment only and allowed to eat normally, to compare the effectiveness of fasting vs. not-fasting,) will be told what cancer patients are currently told: eat to keep your strength up. You need all your strength to survive chemotherapy.

The fasting group will be asked, first, to fast for 24 hours before treatment. If that is determined to be safe, they will be asked to fast for 48, then 72, hours before treatment.

Now, given what I’ve just told you, if you had cancer and were scheduled for chemo next week, what would you do?

More on autoexperimentation soon.

TK Kenyon
Author of RABID: A Novel and CALLOUS: A Novel, a story about free will, neuroscience, fate, the nature of memory, and the End of Days.