Bethesda, Md. Scientists have provided new evidence that using more fish oil than vegetable oil in the diet decreases the formation of chemicals called prostanoids, which, when produced in excess, increase inflammation in various tissues and organs. The results, by William L. Smith, Professor and Chair of Biological Chemistry at the University of Michigan, Ann Arbor, and colleagues, may help in designing new anti-inflammatory drugs with fewer side effects than the ones currently available.

Prostanoids help control blood pressure, fight allergies, and modulate inflammation, but too much of them especially those made from vegetable oils can also lead to increased pain, swelling, and redness in various tissues, Smith says. Our study shows that prostanoids made from fish oil are less effective at causing pain and swelling than those made from vegetable oil and that adding fish oil to the diet decreases the amount of prostanoids made from vegetable oil.

The new study, to be published in the August 3 issue of the Journal of Biological Chemistry , was selected as a Paper of the Week by the journals editors, meaning that it belongs to the top one percent of papers reviewed in significance and overall importance.

Smith and colleagues looked at the mutual effects of both oils by changing their respective amounts in cultured cells. As expected, a relative increase in fish oil lowered the amount of prostanoids from vegetable oil, although not always in the expected proportions.

Both fish and vegetable oils are converted into prostanoids through chemical reactions that are aided by enzymes called cyclo-oxygenases (COX), two types of which COX-1 and COX-2 are involved in the reactions. The scientists showed that, in reactions involving COX-1, when more fish oil is present, it preferentially binds to COX-1, thus limiting vegetable oils access to this enzyme. But in reactions involving COX-2, incr
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26-Jul-2007