THE IMPACT OF EATING ON THE IMMUNE SYSTEM:
 
I am sure everyone has heard the old wife's saying "feed a cold, starve
a fever" (noted in print as early as Withal's 1574 comment, "Fasting is
a great remedie of fever", but the origin is lost in antiquity).  Western
medicine has discounted such adages for a long time; even last year the
saying was contested, and scientific support for the idea is new and
controversial.  However, recent modern evolutionary medicine and
immunology studies may have shed some new light on this axiom.  The
original saying wasn't discussing fever as a spike in body temperature,
but rather as something proceeding in an energetic fashion, and cold
as meaning something proceeding relatively slower; today we term these
"acute" and "chronic" disease states.  A fever to Withal was an
energetic, or acute, disease that may or may not have caused a spike
in temperature.
 
It seems eating has a significant bearing on the immune system (do I
hear a duh?).  Simplistically, there are two different types of immune
responses: antibody-mediated immunity (the humoral immune response) and
cell-mediated immunity (the adaptive immune response).  Humoral immune
system responses are basically those where antibodies circulate in the
serum found in the blood and bathing the tissues.  Simplistically,
cell-mediated immune responses are those that involve the production of
specialized lymphocytes that home in on a specific antigen, such as found
on a bacteria or virus.  In general, the humoral immune response is the
first line of defense, while cell-mediated immune responses kick in
shortly after.
 
As it turns out, recent studies have shown food intake results in
increased levels of gamma interferon production and increased IFN-
production, which increases the adaptive immune response.  On the other
hand, food deprivation stimulates interleukin-4 release, skewing the
immune system toward a humoral immune response.  Simplistically, this
means mild SHORT-TERM anorexia (starve a fever) helps speed the
production of circulating antibodies, while eating (feed a cold) helps
speed the production of specialized lymphocytes (white blood cells).
 
Ok, these are some big words, and the modern findings still have to be
duplicated enough to convince Drs.  Dogma and Demagogue.  It doesn't help
that in a few sentences I am attempting to explain a biochemical response
that could fill a large book with complex and difficult to understand
arguments and proofs.  Still, a growing body of evidence suggests it
means short-term anorexia tends to stimulate the type of immune system
response that fights the initial invasion of a pathogen (the "feverish"
part of the attack), while eating tends to stimulate the type of immune
response that fights a more established enemy (the "cold" part of the
attack).
 
Now, don't be an idiotic butt-head and misunderstand "short-term
anorexia" to mean "starvation," or be so fearful of change in dogma that
you try to place Galileo under arrest, or worse, run around like a
headless chicken screaming the hypothetical mantra, "the sky is falling."
This in no way suggests malnutrition; it just means you eat minimally
during the feverish, or acute part of a disease, making it up a few days
later as the disease "cools" and your immune response shifts from the
humoral to the cell-mediated type.  You are, in effect, starving a fever
and feeding a cold, just exactly what is needed to better stimulate
specific immune responses to help you combat disease.  Your body knows
this better than you, because several other studies have shown that as
part of the fever reaction to disease, the body also produces substances
that are thought to suppress hunger.  How many times have you been sick
and, while you were feverish you were not hungry, but once the fever
broke you became famished?  You are still sick and still have to recover
and kill the germs, but you are just suddenly hungry.  It's a beautiful
creation, isn't it?
 
If this is true, and I believe after reading the papers, attending the
seminars, and discussing it with leading scientists that it probably is,
it means we need to rethink the idea of force-feeding ferrets at the
onset of disease, or when the disease is in an acute phase.  It also
means we should rethink the practice of pushing nutritionally-dense
foods, such as duck soups over-flowing with supplements, on ferrets
impacted by disease but not yet in the recovery phase.  I think hydration
is key, and for the few days of illness there is no need to force-feed a
ferret.  For those few ferrets with little energy reserves, maybe a 5%
glucose formulation might be adequate for them to drink for a couple of
days.
 
Bob C
[Posted in FML issue 4406]