BY RALPH BLUM
There has been a lot written about the
benefits to prostate cancer patients of eating mindfully. Boiled down to
simplest terms, the notion translates as “Just eat less.”
I am always a bit uncertain when I read how
mice prosper on some regime or treatment. Like the diet known as “caloric
restriction,” which has all the normal healthy ingredients and food groups, but
contains 30 percent fewer calories than usual. A New York Times article of July 10, 2009 stated that “mice kept on
such a diet from birth have long been known to live up to 40 percent longer
than comparison mice fed normally.”
Well and good. Further up the chain than
flatworms. But still a long step from human results with caloric restriction.
The next step was to use such a diet with rhesus monkeys to learn whether
primates responded the same way as rodents. However, since rhesus monkeys have
an average life span of 27 years and a maximum of 40, these experiments require
patience.
Dietary restriction seems to set off an
ancient strategy written into all animal genomes, that when food is scarce
resources should be switched to tissue maintenance from breeding.
The rhesus monkey experiment requires another
15 years before the last monkey is expected to die. An eon, compared to
flatworms, which have a life expectancy of about three weeks.
Twenty years after the experiment began, two
studies, conducted by a team led by Ricki J. Colman and Richard Weindruch at
the University of Wisconsin, reported in Science
that the monkeys were showing many benefits, including significantly less
diabetes, cancer, and heart and brain disease. “These data demonstrate that
caloric restriction slows aging in a primate species,” the researchers wrote,
which makes it likely that one could expect the biology of caloric restriction
to produce similar benefits for humans.
While caloric restriction holds great
promise, few people can keep to a diet with 30 percent fewer calories than
usual. So biologists have been looking for drugs that might mimic the effects
of caloric restriction, conferring the gain without the pain, so to speak. In
recent years researchers have had considerable success in identifying the
mechanisms by which cells detect the level of nutrients available to the body.
The goal is to find drugs or compounds that trick these mechanisms into
thinking that famine is at hand, hence the need for a severely restricted diet.
One such compound is resveratrol, a substance
that can, apparently, duplicate in people some of the effects of caloric
restriction. A member of a group of plant compounds called polyphenols,
resveratrol is thought to have antioxidant properties that protect the body
against the kind of damage linked to increased risk for conditions, including
cancer since resveratrol is thought to limit the spread of cancer cells and
trigger the process of cancer cell death or apoptosis.
The problem was that resveratrol, found
primarily in the skin of red grapes (other sources include peanuts and berries)
and, hence, in red wine, is present in quantities too small to have any effect,
unless you drank about three bottles at a sitting. I have long been a fan of
reveratrol, although I have despaired of acquiring enough of the compound to
have a measurable effect on my system.
When
it comes to resveratrol supplements, there isn't any specific dosage
recommendation, and dosages can vary from supplement to supplement, although
they are typically far lower than the amounts that have been shown beneficial
in research studies. Most supplements contain 250 to 500 milligrams of
resveratrol. To get the equivalent dose used in some animal studies, you would
have to consume 2 grams of resveratrol (2,000 milligrams) or more a day. Not
impossible. And arguably not a risk.
Now, Sirtris, a company based in Cambridge,
Mass., has developed several chemicals that mimic resveratrol and can be given
in concentrated doses. One such compound, the drug rapamycin, was reported to
significantly extend life span in elderly mice, though it is not yet clear
whether rapamycin sets off the same circuits as those that increase longevity
in caloric restriction when ingested by humans. But there’s hope!
I remember when I was growing up, my Catholic
classmates, like Dicky Doyle, ate no meat on Fridays. I reckon that at the very
least, the meatless 24 hours gave their digestive systems a rest. Seen as a
mild form of caloric restriction, meatless Fridays might well have had an
impact on human longevity.
Perhaps if I can find a copy of the Beverly
Hills High School alumnae, I can discover who is still around as we enter our
80s. And if they are still in possession of their faculties, perhaps I can
learn what and how they’ve been eating for the last half century.
Meanwhile, there is evidence that those of us
who eat as our ancestors ate do better in avoiding or fighting a variety of
ills, prostate cancer among them.
In my upcoming blogs, I will revisit the eating
habits of cave dwellers.
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