According to a study, trans fatty acids, present in partially hydrogenated vegetable oils in processed foods, interfere with more than one key enzyme in the regulation of blood flow.
University of Illinois emeritus veterinary biosciences professor Fred Kummerow claims that this is the first time that any study has revealed a new way in which these "trans fats" gum up the cellular machinery that keeps blood moving through arteries and veins.
In the study, Kummerow described the two main causes of heart disease, sudden blood clots in the coronary arteries, and atherosclerosis, the build-up of plaque in the arteries to the point where it interferes with blood flow.
"The arteries of someone who dies from atherosclerosis look like old scrub boards as a result of the formation of plaques. They look corrugated, and this plaque buildup continues to the point where it will stop blood flow," said Kummerow.
He said that trans fats contribute to both of these causes of heart disease.
He claimed that trans fats displace, and cannot replace, the essential fatty acids linoleic acid (omega-6) and linolenic acid (omega-3), which the body needs for a variety of functions, including blood flow regulation.
Studies have shown that trans fats also increase low-density lipoproteins (LDLs) in the blood, a factor which some believe contributes to heart disease.
Trans fats also were shown to interfere with an enzyme that converts the essential fatty acid linoleic acid into arachidonic acid, which is needed for the production of prostacyclin (a blood-flow enhancer) and thromboxane (which regulates the formation of blood clots needed for wound healing).
"Trans fats inhibited the synthesis of arachidonic acid from linoleic acid, even when there was plenty of linoleic acid available," said Kummerow.
The new study reports that in addition to interfering with the production of arachidonic acid from linoleic acid, trans fats also reduce the amount of prostacyclin needed to keep blood flowing.
Thus blood clots may more easily develop, and sudden death is possible.
"This is the first time that trans fatty acids have been shown to interfere with yet another part of the blood-flow process," said Kummerow.
He said that the study adds another piece of evidence to a long list that points to trans fats as significant contributors to heart disease.
The study appears in the August 2009 issue of the international journal Atherosclerosis.