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News from News-Medical.net Apr.29, 2007
Digesting protein may be a hidden
problem for some
Medical Research News Published: Sunday, 29-Apr-2007
Protein metabolism presents some serious waste management challenges
for the body.
When protein is broken down, one of the by-products is ammonia.
Ammonia is toxic, so our bodies have elaborate systems for getting
rid of it. Most of the detoxifying work falls to our liver. There,
ammonia travels a multistep pathway featuring five enzymes that turn
it into urea, to be excreted in urine. People with rare genetic
deficits that interfere with the urea cycle often die in childhood.
Other mutations, though, may be responsible for some problems in
adults, reports the May 2007 issue of the Harvard Health Letter.
One in 8,000 American children has a genetic defect that causes one
or more of the enzymes involved in ammonia processing to be
defective or scarce. As these children start to consume protein, the
ammonia begins to pile up. Treatment includes protein restriction,
medications that sop up extra ammonia, dialysis, and possibly liver
transplant. The death rate is high.
Urea cycle disorders are viewed as rare and primarily pediatric
conditions, but there might be a whole range of unrecognized,
genetically determined problems with protein metabolism experienced
by adults. Some people may have mild mutations that compromise a
gene's function and cause slight symptoms. This may explain why one
person eschews meat while another loves nothing more than a steak
meal. Defects in protein metabolism may also explain why some people
have bad reactions to high-protein diets like the Atkins diet.
The Harvard Health Letter notes that someday genetic tests might be
used routinely to diagnose such metabolic disorders, but for now
much more research is needed.
Also in this issue:
Open-fit hearing aids
Is fructose unhealthy?
Standard versus digital mammograms
Atkins wins with weight loss
By the way doctor: Can exercise and diet cure diabetes? Does asthma
go away?
The Harvard Health Letter is available from Harvard Health
Publications, the publishing division of Harvard Medical School, for
$28 per year. Subscribe at
www.health.harvard.edu/health or by calling 1-877-649-9457
(toll free).
http://www.health.harvard.edu/
http://www.news-medical.net/?id=24268
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