Fatty acids are made of carbon atom chains with hydrogen atoms attached. When the carbon chain is full of hydrogen, it is a saturated fat. When unsaturated fatty acids undergo hydrogenation, their chemical structure is changed, which creates a trans fat, similar in shape to a saturated fat.
Unsaturated Fats
Unsaturated fatty acid chains have one or more points of unsaturation where a double carbon bond exists. In chemistry, this usual shape of the double bond is in cis formation.
Saturated Fats
Saturated fats contain no double carbon bonds. Each carbon is surrounded by hydrogen, preventing double bond formation.
Hydrogenation
The chemical process of adding hydrogen to unsaturated fatty acids produces a trans formation, which is more stable than the cis formation.
Trans Fats
Trans fats in foods make them more stable, increase their shelf life and allow them to be heated to higher temperatures. However, they can negatively affect heart health by raising "bad" cholesterol (low-density lipoprotein [LDL]) and lowering "good" cholesterol (high-density lipoprotein [HDL]).
Food Sources of Fats
Saturated fats generally come from animal sources such as meat and dairy, whereas unsaturated fats generally come from plant sources such as nuts, olives and avocado. Trans fats can be found in fast foods and in processed baked goods such as chips, cookies and pies.
References
- "Advanced Nutrition and Human Metabolism;" Sareen S. Gropper, Jack L. Smith, James L. Groff; 2005
- "Nutrition Concepts and Controversies;" Frances Sizer, Ellie Whitney; 2006
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