Freethought & Rationalism Archive

Ramen · 04-08-2003, 07:51 PM

How many of you are already aware of the dangers of trans-fats, aka partially hydrogenated oils? I try to stay away from this stuff. This involves label reading and shopping at natual food stores. This also involves avoiding fast food chain French (freedom) fries. I'm in the NW of the USA and if I want fries, I munch on Burgerville fries (no trans-fats). I believe that In-N-Out Burger in California, Nevada & Arizona also don't use trans-fats in cooking their fries.

Quote:

Once considered relatively benign, studies in the last decade have shown that eating trans fat leads to higher low-density lipoprotein (LDL), the "bad" cholesterol, and higher total cholesterol. It may also lower high-density lipoprotein (HDL), the "good" blood fat, although the panel noted that the evidence here isn't consistent.

Since high LDL and total cholesterol are linked to heart disease, scientists believe people who eat foods rich in trans fatty acids are more vulnerable to heart attacks, strokes, and other cardiovascular problems

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Godot · 04-09-2003, 02:46 AM

trans-fatty acids are actually an isomer. The cis- formation occurs naturally and the body can "recognise" it as the type of fatty acid it is (whether that particular molecule alters blood lipids in a positive fashioin, negatively, or is inert). The trans- formation only results from the hydrogenation process. Regardless of the actions of a given fatty acid in the body, if it is present as the trans- isomer, the body treats it as the equivalent of a saturated fatty acid.

Ramen · 04-09-2003, 10:05 PM

The body does not treat trans-fats the same as saturated fat.

Quote:

Basically, trans fatty acids cause alterations to numerous physiological functions of biological membranes that are known to be critical for cell homeostasis, e.g., appropriate membrane transport and membrane fluidity, and these fatty acid isomers produce alterations in adipose cell size, cell number, lipid class and fatty acid composition.

To understand what trans fatty acids are you have to understand what fatty acids are. Fatty acids are basically chains of carbon with a carboxyl group (COOH) at one end that can react (e.g., combine) with another molecule.

When fatty acids are in fats or oils they are combined with glycerol in the proportions of three fatty acid molecules to one glycerol molecule and they form triacylglycerols or in common terminology, triglycerides.

Fatty acids come in different chain lengths ranging from three carbons long (propionic acid) to 24 carbons long (lignoceric acid). These fatty acids are either "saturated" (with an adequate number of hydrogen atoms) and chemically stable, or they are "unsaturated" (missing adequate hydrogens) and chemically unstable.

If the unsaturated fatty acids are altered by partial hydrogenation to straighten the chains so that they have some of the physical packing properties of saturated fatty acids they have had their "cis" double bond changed to a "trans" double bond and they turn a technically mostly unsaturated oil into a solid fat.

The trans fatty acids are the same length and weight as the original "cis" fatty acid they were formed from, and although they have the same number of carbons, hydrogens, and oxygens they are shaped differently in space.

The term that is used is that they are "isomers." The problem arises when a large number of the trans fatty acids are consumed from foods and they are deposited in those parts of the cell membranes that are supposed to have either saturated fatty acids or "cis" unsaturated fatty acids; under these circumstances the trans fatty acids essentially foul up the "machinery."

Although the trans fatty acids are chemically "monounsaturated" or "polyunsaturated" they are considered so different from the "cis" monounsaturated or polyunsaturated fatty acids that they cannot be legally designated, e.g., monounsaturated for purposes of labeling. Most of the trans fatty acids produced by the partial hydrogenation process are chemically monounsaturates.

There have always been small amounts of one kind of trans fatty acids in the human diet from the ruminant fats (dairy, sheep, goat, deer, buffalo, antelope, etc.) because the microorganisms in the rumen try to get rid of the polyunsaturated fatty acids that are found in the plant foods eaten by these animals.

In the early days of trans fatty acid research, the researchers assumed that the trans fatty acids found in ruminant fats were no different than those produced by partial hydrogenation in the factory.

But the studies showed that not only was the amount much smaller (e.g., the fat in butter might be 2-3% of the ruminant trans), the effect on the "machinery" in the cell membranes was not different than without the trans. Yet all studies feeding the trans produced by partially hydrogenating the vegetable oils showed the adverse effect on the cell "machinery."

The various mechanisms through which the trans fatty acids disrupt function are related in part to the ability of trans fatty acids to inhibit the function of membrane related enzymes such as the delta-6 desaturase resulting in decreased conversion of e.g., linoleic acid to gamma-linolenic acid or arachidonic acid; interference with the necessary conversion of omega-3 fatty acids to their elongated tissue omega-3 fatty acids; and escalation of the adverse effects of essential fatty acid deficiency.

click here for the full article.

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04-09-2003, 02:46 AM	#2
Godot Veteran Member Join Date: Mar 2003 Location: Calgary Posts: 1,335	trans-fatty acids are actually an isomer. The cis- formation occurs naturally and the body can "recognise" it as the type of fatty acid it is (whether that particular molecule alters blood lipids in a positive fashioin, negatively, or is inert). The trans- formation only results from the hydrogenation process. Regardless of the actions of a given fatty acid in the body, if it is present as the trans- isomer, the body treats it as the equivalent of a saturated fatty acid.

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