FROM THE AUTISM LIST
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Milk protein may play role in mental disorders

NEW YORK, Apr 01 (Reuters Health) -- Mental illnesses such as autism and
schizophrenia may be linked to the improper digestive breakdown of
casein, a protein found in milk and milk products, US researchers  report.

The study findings suggest that a malfunctioning enzyme in the intestine
may be to blame. This dysfunction may produce high levels of smaller
protein compounds called exorphins, which infiltrate the brain and cause
hallucinations and other disturbances.

"We now have proof positive that these proteins are getting into the
blood and proof positive that they're getting into the areas of the
brain involved with the symptoms of autism and schizophrenia," explained
study lead author Dr. J. Robert Cade of the University of Florida in
Gainesville.

The findings are reported in two papers published in the March issue of
the journal Autism.

In their first study, the team report that the brains of rats injected
with one casein-related byproduct -- human beta-CM7 -- showed uptake of
the protein in neurological centers previously linked with autism and
schizophrenia. Affected areas included those influencing vision,
hearing, and communication.

In a statement from the University of Florida, Cade said these findings
"could explain several things one sees in autism and schizophrenia, such
as hallucinations. If part of the brain puts out a false signal because
of (beta-CM7), it could result in the person seeing something that's not
really there; either a visual or auditory hallucination could occur."

In healthy humans, casein breakdown results in only minimal production
of beta-CM7 and other exorphins. Cade speculates that this process may
be impaired in schizophrenic and autistic individuals. Indeed, the
preliminary results of his team's current studies in autistic and
schizophrenic children suggest that these children have up to 100 times
the normal level of milk proteins in blood and urine. The researchers
also found that the schizophrenic or autistic symptoms of about 80% of
these children fade or disappear after they are switched to
milk-free diets.

The connection between autism, schizophrenia and milk proteins was
supported by the results of the second report published in the journal.
In that study, Cade and co-author Dr. Zhongjie Sun found that
intravenous administration of beta-CM7 produced "remarkable" behavioral
changes in rats.

These behavioral changes ranged from restlessness "with teeth chattering
and with rapid respiration" about a minute after administration, to
inactivity as well as avoidance of other animals within about 7 minutes
of injection, according to the authors.
The rats were also oblivious to a bell ringing in near proximity
following beta-CM7 administration. Cade said "this struck us as
interesting because many mothers of autistic children comment that they
sometimes seem to be totally deaf -- they talk to their children and
they just don't seem to hear them."

Cade cautioned that more research is needed to confirm these findings.

Commenting on the studies, Dr. Bennett Leventhal of the University of
Chicago School of Medicine, noted that schizophrenia and autism are
"distinctly different disorders" with complex origins. "It is certainly
possible that these (digestive) genetic abnormalities could lead to the
metabolic effects Dr. Cade mentions," he explained in a statement,
"though there is not substantial support for that at this time."

SOURCE: Autism 1999;3:67-83, 85-95.

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