Trans Fats and why to Avoid them

I would be remiss if I talked about butter vs margarine and oils and whatnot and I didn’t mention Trans Fats which is one of the hot button topics du jour.

Fats are hydrocarbons (like oil and gasoline) meaning they are built upon a backbone of Carbons and hydrogens.  If you have a single bond between the carbons then each carbon has 2 hydrogens attached to it (if it’s in the middle of the chain, 3 if its on the end).  -H2C-CH2- for example.  This is called a saturated hydrocarbon, since every available spot has a hydrogen.  If you have a double bond between the carbons there is one less spot for hydrogens and the carbons around the double bond with only have 1 hydrogen each. -HC=CH- for example.  This is called being unsaturated.

Fatty acids in food are made of of a glycerol molecule with three hydrocarbon tails.  Different combinations of saturated and unsaturated tails give the fats their characteristics and why some fats (beef fat, pork fat, vegetable shortening) are solid and some fats (olive oil, peanut oil, etc) are liquid.

I can’t draw it here, but the hydrogens can be in two configurations around the double bond.  The “cis” configuration means that both hydrogens are on the same side off the double bond.  Both top, or both bottom.  This causes a bend in the carbon chain.  In the “trans” configuration they are opposite each other.  One top and one bottom.  This keeps the chain straight.  Trans fats are very rare in nature although they do occur in animal fats in very very small quantities.  The bent chains can’t stack on top of each other, which is what keeps unsaturated fats liquid.

When they hydrogenate unsaturated vegetable oils, they break the double bonds and add hydrogens in the empty spots.  This turns an unsaturated fat into a saturated fat.  This in itself is not a problem, however some forms of hydrogenation have been known to form small amounts of trans fats where the hydrogens get switched around but they don’t break the double bonds.

Why is this bad? The reason this is bad, is because the now straightened chains will stack in with the other saturated fats.  Your body will see them as saturated and store them as such.  This leads to a problem where you have double bonds in with saturated fats and some chemicals can break these double bonds and oxidize them (hence why we eat antioxidants) and this can lead to cancer.

Is this something you should worry about? At this point, no probably not.  The swift actions of food companies have pretty much eradicated them from the food supply and also they won’t really hurt you in small quantities.  Both of the margarines I have in my fridge have Zero Trans Fats.  I have seen some products with 0.5 to 1 g of trans fats but I’m sure before long those will be gone.

Our college professors told us to never use Wikipedia as a source, but it’s easier to access online then trying to scan in a textbook, so for more info on Fatty Acids check out http://en.wikipedia.org/wiki/Fatty_acid

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  • About Me

    I am a recent graduate in Food Science (NC State, 2009) and I work for a major food manufacturing company. I love food, but I can no longer eat anything that crosses my path. About 24 months ago I begin a serious struggle to get my obesity under control and reduce my chances of developing Type II diabetes. Since September of '09 I have lost 50 pounds and I still have a long ways to go. I've started eating better and exercising more, including taking up running.