February 4, 2004
NUTRITION NEWS FOCUS
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Today's Topic: Unsaturated Fat and Your Blood Vessels

Most of us know that consuming unsaturated fat is supposed to lower
serum cholesterol and keep our arteries unclogged.  However, a few
studies have found the opposite; higher polyunsaturated fat intake was
correlated with more heart disease.  A new study attempts to explain
this by reporting that a gene controlling metabolism of unsaturated
fat puts people at risk.

The gene codes for an enzyme called 5-lipoxygenase and is involved in
metabolizing polyunsaturated fat to hormone-like chemicals called
leukotrienes.  Each person has two genes for this enzyme.  In a study
of 470 people in Los Angeles, one in 15 had variants of the common
genes.  Having two variant genes was associated with significantly
more atherosclerosis of the carotid artery in the neck that supplies
blood to the brain.  There were marked differences by ethnicity in the
results.  The variant genes were six time more common in blacks than
in whites, with Asians also having a high prevalence.  The study was
published in the January 1, 2004 edition of the New England Journal of
Medicine.
< http://content.nejm.org/cgi/content/abstract/350/1/29 >

HERE'S WHAT YOU NEED TO KNOW:  Although polyunsaturated
fat lowers cholesterol in most people, the effect seen here was not
mediated through serum lipids but probably through effects on
inflammation.  Arterial disease is becoming more accepted as a chronic
inflammatory condition rather than a problem with cholesterol only.
Intake of omega-3 fatty acids, primarily from fish, blunted the effect
of the other polyunsaturated fats on promoting arterial disease.