"Fasting Before and After Chemotherapy Put to the Test"
The first randomized prospective clinical evaluation
of the effects of fasting on chemotherapy,
the incidence of chemotherapy-induced nausea
and vomiting in cancer patients was published in 2014,
but the patients were dogs.
Cancer-bearing dogs presenting at a veterinary hospital were
randomized to be fasted for 24 hours before chemotherapy,
and those that were, were significantly less likely
to suffer from vomiting
only 1 in 10 compared to 2 out of 3 in the non-fasted group,
which is great, but what can that tell us about human medicine?
Evidently, not much.
It is nearly impossible to rely on most animal data
to predict whether or not an intervention will have
a favorable clinical benefit-risk ratio in human subjects.
For example, mice have a metabolic rate approximately
seven times higher than humans,
so a single day of fasting can cut lean body mass about 15%.
That would take over a month of fasting in people.
So that dramatic study on mice showing 100% alive versus
100% dead on high dose chemo depending on whether
they were fasted for 60 hours, what can that really tell us?
And when it comes to cancer, rodents can bear
massive tumor loads, whereas people generally
waste away and die when tumor masses
reach just a thousandth of our body weight.
You can't even necessarily extrapolate from one rat to another
even within the same strain bought from different dealers.
The only way to see what happens in humans,
the only way to guarantee findings are relevant is to study people.
The theory is that combining fasting cycles with chemotherapy
could extend the survival of advanced-stage cancer patients
by both retarding tumor progression and reducing side effects,
or even providing an alternative to chemotherapy altogether
in early-stage cancer patients,
but that's all contingent on it being confirmed in human clinical trials.
First there were case series:
several patients diagnosed with a variety of cancers
elected to undertake fasting prior to chemotherapy
and shared their experiences.
Those who underwent chemo both with and without fasting
reported a reduction of fatigue, weakness, and
gastrointestinal side effects while fasting; in fact felt better
across the board with zero vomiting in the fasting group.
The weight lost during the few days of fasting was rapidly recovered
in most of the patients and did not lead to any detectable harm,
so overall was looking feasible, safe,
with the potential to ameliorate side effects.
But only randomized clinical studies could tell for sure,
and so here we go.
Breast and ovarian cancer patients fasting, starting 36 hours
before and ending 24 hours after chemotherapy,
and it did appear to improve the quality of life and fatigue,
but another study found no such beneficial effects.
There did appear to perhaps be less bone marrow toxicity
given the higher counts of red blood cells and platelet-making cells,
but no benefit when it came to killing off white blood cells --
the immune system cells -- so that was a disappointment.
Perhaps they didn't fast long enough?
They only fasted 24 hours before and after.
To find out the optimal duration, 20 cancer patients were split up
into three groups, fasting for 24, 48, or a total of 72 hours.
All those in the 24-hour group suffered nausea after chemo,
but less than half in the 72-hour group.
And most were vomiting in the 24-hour group,
but none in the longest fasting group.
Longer fasting groups also tended to suffer less nerve damage
and less serious bone marrow suppression.
Even after 24 hours of fasting, two cycles of chemo can
knock people's white blood cells down to sub-optimal levels, but
with 72 hours, chemo knocked their immune system down but not out.
OK, so short-term fasting may reduce chemotherapy-induced toxicity,
but what I want to know is if it makes it work better?
A systematic review of 22 studies found that overall fasting
was found to not only reduce chemotherapy side effects, like
organ damage, immune suppression, and chemotherapy-induced death,
but also to suppress tumor progression, including
tumor growth and metastasis, resulting in improved survival, but...
nearly all of the studies were done on lab animals.
The studies on humans are limited to evaluating safety
and side effects. The tumor- suppression effects of fasting --
for example, its influence on tumor growth, metastasis and prognosis --
have not been evaluated until now.
To be continued ...