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Definition Time
L
et’s start with a few terms: you can’t expect to understand a new
topic unless you become familiar with the use of its special words
or jargon.
We need to establish two specific phenomena: food allergy proper
and food intolerance caused by genetic factors and specific metabolic
incompatibilities to foods.
To begin with, what do we mean by allergy? It is actually not a very
straightforward term, though it is used a lot. The word was first coined in
1906 by an Austrian physician, Von Pirquet, so obviously he had the right
to say what he meant by it. He specified it as ‘an acquired, specific, altered
capacity to react to physical substances on the part of the body.’
Note the word acquired: it means you do not inherit the sensitivity.
This is not like the toxic venom of a snake, where the first dose is just as
harmful as later doses.
According to our understanding of the allergy mechanism, you
need to be exposed to the substance before you develop a reaction to it.
This exposure may be as slight as one prior contact, yet it must take place.
It is confusing, perhaps, that many infants are born with allergies, but that
does not violate this stipulation. The fact is that babies in the womb are
exposed to a great many potentially allergenic substances via the mother’s
diet and bloodstream. This is how we think they acquire the sensitivity.
The term specific means that the reaction associated with a particular
substance is quite unique, even though the results may not be. Thus tomato
may make you ill, and so may house dust, but the reacting mechanism in
each case is not the same, though the symptom that is caused may well be.
Altered is really a way of saying that it is peculiar to the individual in
question, not something that the rest of us are troubled by. This is important,
for otherwise we fail to distinguish the special problems of allergy from
those of straightforward poisoning. Thus cyanide or muscarine (from the