"Fasting-Mimicking Diet Before and After Chemotherapy"
Short-term food withdrawal during chemotherapy may begin to solve
the long-standing problem with most cancer treatments:
how to kill the tumor without killing the patient?
Short-term fasting -- for example,
for 48 hours before chemo and 24 hours afterwards --
may reduce side effects, reduce chemotherapy-induced toxicity.
However, the potential tumor- suppressing effects of fasting --
for example, its influence on tumor growth, metastasis and prognosis --
have not been evaluated until now.
No, actually, sadly, they mean "have not been evaluated until now,"
meaning they have not been evaluated yet, period.
So in answering the question to fast or not to fast before chemotherapy,
it should be emphasized that the evidence provided
by human studies is still very limited.
Some argue that reducing the side effects alone
could improve efficacy,
since patients could withstand higher doses.
For example, the heart and kidney damage associated
with the widely prescribed anti-cancer drugs limit
their full therapeutic potential. It's not clear, though, that
maximizing the tolerated chemo dose would achieve
longer survival or better quality of life.
For now, I think we should just be satisfied with
the fewer side effects for fewer side effects' sake.
Some cancer docs urge caution, concerned about malnutrition.
That concern is echoed in official guidelines
on nutrition in cancer patients.
Because of the risks of malnutrition and,
yeah, maybe a day or two might not hurt,
but because patients might be tempted to prolong fasting
episodes without firm evidence of a benefit, they feel
fasting during chemotherapy cannot be recommended.
Fasting proponents agree that patients with severe weight loss,
muscle wasting or malnutrition -- probably not good candidates
for even short-term fasting.
But out of the hundreds of patients that have been tracked,
there's no evidence of severe adverse events in terms of malnutrition
or weight loss with short-term fasting or fasting-mimicking diets.
And those patients who did experience a weight loss
during fasting typically recovered their weight
before the subsequent cycle of chemo without detectable harm.
But look, even if there is a risk, we're talking about cancer here.
Accepting trade-offs is kind of the name of the game.
People are willing to put up with the risk of severe,
even life-threatening side effects all the time.
And even if it just helped alleviate some of the side effects,
it might be worth a try.
Of course, meanwhile Big Pharma is busy trying to come up with drugs
aimed at reproducing the beneficial effects of fasting.
Although fasting mimicking drugs may be preferred by patients
who would rather pop a pill than go without eating,
it will be years before they'll ever be on the market,
and it's hard to imagine drugs will be developed that are
both as effective and as safe as fasting.
So is there anything we can tweak in our diet
to get similar benefits without having to fast?
The way fasting works is by reducing levels
of a cancer-promoting growth hormone known as
insulin-like growth factor 1.
It's the reduced levels of IGF-1 that mediate
the differential protection of normal and cancer cells
in response to fasting
and improves chemo's ability to kill cancer
but spare normal cells. How do we know this?
Because restoration of IGF-1 was sufficient to reverse
the protective effect of fasting. Check it out.
Here's the growth of two cancer cell lines, breast cancer and melanoma,
in a petri dish after being exposed to chemotherapy.
Survival rates dropped down into the 60s or even 20s.
But the same dose in starved cells works even better.
Same dose, same starvation, but drip back a little IGF-1
and the starvation benefit vanishes.
So reducing IGF-1 signaling may provide the dual benefits
by protecting normal cells while reducing tumor progression
and may even help prevent the cancer in the first place.
As I explained before in my "How Not To Die from Cancer" video,
and an important video about animal protein --
which kind of gives away the punch line --
but fasting isn't the only way to drop IGF-1 levels.
Yes, a few days of fasting can cut levels in half,
but that's largely because you're cutting your protein intake.
Protein is a key determinant of circulating IGF-1 levels in humans,
suggesting that reduced protein intake may become
an important component of anticancer and anti-aging
dietary interventions, particularly a reduction in animal protein.
If you compare those eating strictly plant-based diets, getting about the
recommended daily intake of protein, 0.8 grams per kg of body weight,
and compare them to people just as slender but eating more typical
American protein intake, going on a calorie-restricted diet
may lower IGF-1 a little, but eating a plant-based diet can lower it more.
So not only may a diet centered around whole plant foods
down-regulate IGF-1 activity, potentially slowing the aging process,
but may be a way of turning anti-aging genes against cancer.