John_Yudkin_-_Pure_White_and_Deadly_revised_1986_OCR

Pure, White and Deadly
and decay occurred only in children who did not clean their teeth
regularly; if they did clean their teeth regularly, they had little caries
even when they ate a lot of sugary foods.
Many experiments have been done, especially in anim~s, to see
what changes in diet affect the teeth. As always, the preclse resul~s
differ according to what animals were used, exactly what the expenmental
diets were, how the diets were given, and for how long. The
general results, however, seem clear. When there is no carbohydrate,
little or no caries is produced. Diets containing starch, .or
bread (brown or white), produce either the same amount of canes
or a very little more. Diets with any sort of sugar produce much
more caries, and the most 'cariogenic' sugar is sucrose.
The best-known experiments with children are those done by
the British Medical Research Council in 1950, and in the town of
Vipeholm in Sweden a few years later. The first study lasted for two
years and showed that the addition of sugar during mealtimes did
not increase the amount of caries in children. The second study
compared sugar given in different ways for four years, and found
that little additional caries occurred if the sugar was taken at meals,
but much more occurred when it was taken as sweets between meals,
and especially if it was taken as sticky toffees between meals.
Obviously, what matters is whether the sugar is in contact with the
teeth for some time. Sticky sweets and cakes and biscuits between
meals are the chief culprits, especially if their residue is allowed
to remain without being exposed to a good and prolonged tooth
brushing.
A great deal of attention has been directed towards what is called
'rampant caries'. The custom seems to have grown of giving babies
dummies to suck that have a small container in which syrup is put.
The effect of this, or of giving ordinary dummies constantly dipped
into sugar, is that the babies' teeth become rotten as they erupt, so
that at the age of two or three years their mouths are full of blackened
stumps. In one survey, one baby in 12 was found to be suffering
from rampant caries; in another, the figure was one in eight.
One of the most interesting and unexpected of the observations
of the role of sugar in producing dental caries comes from a study
of a rare disease, hereditary fructose intolerance. Only a few faInilies
have been discovered with members suffering from this disease, and
they become violently sick whenever they get fructose, or sucrose,
which you will recall is a compound made up of equal amounts of
glucose and fructose.
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A host of diseases
Very early in life, therefore, they learn to avoid fruits and anything
containing sucrose. They can and do eat starchy foods, since starch
is digested to give only glucose. But even though they eat lots of
white bread, made from what people like to call 'refined flour', they
have very little caries, and what they do have is of a very minor
degree.
One day perhaps we shall be able to immunize children against
the bacteria that are involved in producing caries. But although
experiments aimed at producing immunity to caries have been in
progress for nearly 20 years, a practical vaccine has still not been
. produced.
Damage to the skin
In measuring the amount of sugar consumed by
hospital patients, I was chiefly illterested in those with coronary
disease. But it occurred to me that it would be interesting to see
how much sugar was taken by patients with two or three other
conditions. There are, for example, conditions such as acne (blackheads)
which occur quite frequently in teenagers, and which doctors
believe is caused or made worse by the eating of confectionery .
We measured sugar intake in these patients and compared it with
that of people of the same age and sex without acne . We also decided
to look at another common skin disease called seborrhoeic dermatitis,
but not this time because diet had been implicated by physicians.
The reason was that this condition has to do with the
secretion of the glands in the skin of the oily substance called
'sebum'. There is some evidence that this material is altered when
the diet is rich in sugar. So we also measured the sugar intake of
patients with this disease, and compared it with that of people without
seborrhoeic dermatitis, each one chosen so as to be the same sex
and age as a patient with the disease.
It turned out that the acne patients were not taking any more
sugar than the control subjects, but that those with seborrhoeic
dermatitis were taking appreciably more.
The implication of these results is that sugar is not involved in
producing acne, but may be involved in producing seborrhoeic
dermatitis. We could extend these conclusions by saying that it is
unlikely that acne patients would get better if they ate less sugar,
although it may be that they are especially sensitive. They might
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