Nutrition Science and Everyday Application - beta v 0.1

274 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
A WORD ABOUT TRANS FATS
The carbon-carbon double bond in an unsaturated fatty acid chain can result in different
shapes depending on whether the fatty acid is in a cis or trans configuration. When the
hydrogen atoms are bonded to the same side of the carbon chain, it is called a cis fatty acid.
Because the hydrogen atoms are on the same side (and repelling one another), the carbon
chain has a bent structure. Naturally-occurring fatty acids usually have a cis configuration.
In a transfatty acid, the hydrogen atoms are bonded on opposite sides of the carbon chain,
resulting in a more linear structure. Unlike cis fatty acids, most trans fatty acids are not found
naturally in foods, but instead are a result of an industrial process called hydrogenation.
Hydrogenation is the process of adding hydrogen to the carbon-carbon double bonds, thus
making the fatty acid saturated (or less unsaturated, in the case of partial hydrogenation).
Hydrogenation creates both saturated and trans fatty acids. Trans fatty acids are actually
unsaturated fatty acids, but they have the linear shape of saturated fatty acids. (The carbon
chains are not bent like naturally-occurring unsaturated fats.) The trans fatty acids formed
through partial hydrogenation have an unusual shape, which makes their properties
and actions in the body similar to saturated fatty acids.