By Michelle Bohan Brown, PhD

When discussing diet and heart health, one usually hears “Eat less saturated fat per day,” “Eliminate trans fat,” and “The fat you eat should be rich in mono- and polyunsaturated fats.” All of these fats can be found listed on nutrition labels, but what are they, and what does research show about the relationships between these fats and cardiovascular disease?

What do trans, saturated, mono- and polyunsaturated fat mean? Their names refer to the chemical structure of their fatty acid (“fat”).  Saturated fats only have single bonds between each carbon, represented by the single lines. Unsaturated refers to a double bond between each carbon represented by two lines. Mono unsaturated fats have only one double bond and polyunsaturated fats have two or more double bonds. Trans fats are mono- and polyunsaturated fats that have the double bond in a trans orientation. The other orientation that a double bond can be in is the cis bond. Both the trans and cis orientations are shown. Trans fats look and behave like saturated fats. Below are examples of each of the categories of fat described above.