Sugar Increases Polio Risk
-- Lessons For Other Viral Infections
The following is a chapter from the book
Diet Prevents Polio written by Benjamin P. Sandler, M.D.,
and published in 1951, at the height of the polio epidemic.
Low Blood Sugar And Susceptibility To Polio
During my research I observed a large number of patients
who had symptoms that were caused by low blood sugar.
They complained of the symptoms previously described, namely:
- abdominal pain
- frequent sweats
- occasional fainting spells.
Most of these patients were malnourished, which, physiologically,
meant subnormal liver glycogen storage.
Their diet was deficient in protein and consisted largely of
the cheaper starchy foods.
I noted that these patients also had poor resistance to infections
such as colds, sore throat, grippe, influenza, bronchitis, and pneumonia.
By increasing the protein content of their diet and by
reducing the sugar and starch content, they improved considerably.
They became stronger, more vigorous and buoyant, and had fewer infections.
A few of these patients had had polio in childhood.
Observations of these patients over a long period of time led me to suspect
that their susceptibility to infection was possibly due to
their poor diet with its high sugar and starch content.
Their increased resistance to infection with a better diet confirmed this suspicion.
It then occurred to me that their susceptibility to polio could be explained
on a similar dietary basis.
Specifically, I suspected that children and adults contracted polio because of
low blood sugar brought on by a diet containing sugar and starch.
I reasoned that the polio virus was able to cross tissue barriers,
reach the brain and spinal cord, invade the nerve cells,
damage or destroy them and cause paralysis.
And I further reasoned that if the blood sugar never fell below 80 mg,
polio could never result.
I suspected that during a polio epidemic only those children and adults
who experienced periods of low blood sugar would contract the disease and
that those individuals who were in actual contact with the virus but
who maintained normal blood sugar levels would not contract the disease.
Thus, it remained to prove that low blood sugar could be
a factor in susceptibility to polio.
And, after this had been proved, the following questions had to be answered:
· What causes low blood sugar in humans?
- How can low blood sugar be prevented?
The prevention of low blood sugar would thus mean the prevention of polio.
Before describing the experiments performed, I should like to make
a preliminary summary and state without reserve that:
1. Low blood sugar is a factor of susceptibility to polio.
2. Low blood sugar occurs frequently in children and adults
and is caused chiefly by a dietary error,
namely, the consumption of sugar and starch
- Correction of this dietary error will prevent low blood sugar
- and thus prevent polio.
An experimental method to prove that low blood sugar was a factor
of susceptibility to polio was readily available.
In 1938, the only laboratory animal that could contract polio
by experimental inoculation was the monkey.
All other laboratory animals were completely resistant to the polio virus.
The rabbit is one of these resistant animals.
Without knowing the blood sugar range in the monkey and rabbit,
it was suspected that the blood sugar in the monkey reached lower
levels than in the rabbit.
These suspicions were found to have a basis in fact through the investigations of
Drs. Jungeblut and Resnick of Columbia University who studied blood sugar levels
in monkeys, and through the investigations of Drs. du Vigneaud and Karr of
Cornell University who studied blood sugar levels in rabbits.
In monkeys, blood sugar values as low as 50 mg. were observed,
whereas in the rabbit, values below 100 mg. were never observed.
In numerous determinations made on rabbits I have never obtained values
below 100 mg.
It was therefore concluded that the susceptibility of the monkey to the polio virus
was due to the fact that its blood sugar fell to subnormal values,
and that the resistance of the rabbit might be associated with the fact that
its blood sugar never fell below 100 mg, and that at this concentration
cellular oxidation of glucose in the nervous system and other organs
would be maintained at such a level as to enable the cells
to protect themselves against invasion by the virus.
Physiologists have stated that the normal blood sugar level of 80 mg.
holds true for all mammals.
The next step was to lower the blood sugar of the rabbit to subnormal values
with insulin injections, and then inoculate the rabbit with polio virus.
This was done and it was found that the rabbits became infected
and developed the disease.
The details of these experiments were published
in the American Journal of Pathology, January, 1941.
Some rabbits showed signs of infection 8 to 10 hours after inoculation.
I wish to stress this short period of incubation in the rabbit because
it demonstrates that polio can develop in a short period of time.
This is important, as we shall learn later, when we discuss
the onset of polio in humans within 24 hours after severe physical exertion.
The rabbit is also resistant to the dog distemper virus.
One of the largest research laboratories has conducted much research
with this virus and when I informed the members of the staff about my success
in inoculating rabbits with polio virus after lowering the blood sugar,
they inoculated rabbits with the dog distemper virus after insulin and reported
to me that they observed signs of infection in the rabbit for the first time.
This corroborating experiment indicates that low blood sugar
may cause susceptibility to many infections.
I was thus satisfied that low blood sugar was a factor of susceptibility
to the polio virus in monkeys, and that rabbits could be rendered susceptible
after their blood sugar was lowered with insulin
(Insulin, as you probably know, is the hormone which diabetics inject into themselves
in order to keep their blood sugar within normal range. It is a quick-acting drug and
can lower the blood sugar within an hour or so after injection).
I concluded that the concept that low blood sugar created susceptibility to polio
in both monkeys and rabbits could be applied to humans as well.
What Causes Low Blood Sugar in Humans?
The next step in the solution of the polio problem was to find out the causes of
low blood sugar in humans. Fortunately the answer to this problem was already at hand.
It has been found that the consumption of sugar and starch and foods
containing these substances were the chief causes of low blood sugar.
When patients drank a solution of pure glucose they had a period of low blood sugar
which began one to two hours after the glucose was taken and which lasted for
one to two hours, and longer.
This study of the blood sugar is called the "glucose tolerance test" and is employed
for the detection of hypoglycemia or hyperglycemia.
When they ate a meal containing sugar and starch they also had periods of low
blood sugar which came on an hour or so later and which lasted for
from one to two hours.
The low blood sugar was more marked and lasted for a longer time
after the glucose solution than after a meal containing starch.
It is an established fact that this paradoxic depressant effect on the blood sugar level
is more readily exerted by sugar than it is by starches. I have observed these results in
hundreds of cases and similar results have been obtained by other investigators.
It is a surprising paradox:
the more sugar (and starch) you eat,
the more likely you will develop low blood sugar.
Drs. E. P. McCullagh and C. R. K. Johnston have shown how
the glucose tolerance test is readily influenced by diet.
Thus the second problem:
What can cause low blood sugar in the human? was solved.