Thinking they are doing the right thing, parents forbid
their children to touch dirty objects and carry toys in
their mouths. This is actually a mistake. “There
is an inverse relationship between the level of hygiene
and the occurrence of allergies,” explains Dr Guy
Delespesse, a professor in the Faculty of Medicine at Université de
Montréal and Director of the Allergy Research Laboratory,
located at Notre-Dame hospital in the CHUM. In fact, the
more time a child spends in sterilized conditions, the
higher its risk of developing an allergy during its lifetime.”
The mechanisms that govern our immune system are better
and better understood. In short, the lymphocytes, the sentries
of our immune system, recognize foreign substances. When
an intruder is detected, these lymphocytes produce antibodies
whose mission it is to neutralize the foreign agent. However,
in allergic patients, the immune system is out of control. “The
patient develops an immune response to a component of his
environment,” the allergist points out. “However,
the response is abnormal. In fact, the component to which
the patient immunizes himself is absolutely harmless to
the human body.”
Why does the immune system turn against the body, which
it is supposed to defend? There are signs that the intestinal
flora is one cause. “There is not much research in
this field,” observes Dr Delespesse. “The role
of the bacteria in our intestines is to educate our immune
system. They teach it how to react when confronted with
foreign substances.”
Ideally, the bacterial flora that line the intestine should
be varied and rich. Recent studies have demonstrated that
administering probiotics to newborns or to future mothers
in the last third of their pregnancy may reduce the impact
of allergies during the first two years of the child’s
life by 50%. And where are these probiotics found? “They’ve
been used for centuries to make yoghurt,” the researcher
answers.
There is currently only one yoghurt whose merits have been
scientifically proven. But don't look for it at the corner
store: it is only found in Europe. “If the exploratory
studies are confirmed, all physicians will recommend that
future mothers eat yoghurt and give some to their infants.
A market worth several billion dollars will open up to
dairy companies,” remarks the researcher, who serves
as scientific consultant to one of these companies. The
merits of probiotics appear to be a lot less obvious in
adults. “Training our immune system is like a child's
education,” adds Dr Delespesse. “The longer
you wait to learn to read, the harder it will be. Similarly,
to be effective, the bacterial flora must educate the immune
system as early as possible.”
Researcher: Guy Delespesse
Telephone: (514) 890-8000, extension 25395
Email: guy.jt.delespesse@umontreal.ca
