A Comparison of Saturated and Unsaturated Fats
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Butter versus Margarine
Based on findings, the distinguishing characteristic between margarine and butter is not the caloric content, as they are about equal, but the composition of their fatty acids. About 62% of the fatty acids in the butter are saturated compared with 20% in margarine. During the manufacturer of margarine and some other vegetable shortenings, unsaturated corn, soybean, or sunflower oil is partially hydrogenated---a process called hydrogenation wherein hydrogen is added to the oil.
This causes the chemical structure of the original polyunsaturated oil to be arranged to a liquid not found in nature that is more hardened (saturated) but not as hard as butter. When one of the hydrogen atom along the carbon chain moves from its naturally occurring position(cis position) to the opposite side of the double bond that separates two carbon atoms (trans position), the restructured fatty acid is referred to as a trans unsaturated fatty acid. From 17 to 25% of the fatty acids in margarine are trans unsaturated fatty acids, compared with only 7% in butter fat.
The fact that margarine is made from vegetable oil, it contains no cholesterol; butter, on the other hand, is made from a dairy source and contains between 11 to 15 mg of cholesterol per teaspoon. The current controversy over margarine versus butter centers on the possible detrimental health effects of trans, unsaturated fatty acids. A diet high in margarine and other foods containing partially hydrogenated vegetable oils increases LDL cholesterol concentration to about same degree as a diet high in saturated fat. Unlike saturated fats, however, they also decrease the concentration of the beneficial HDL cholesterol. Scientists estimate that the dietary trans unsaturated fatty acids do contribute to increased risk for heart disease.
Since there seems to be a controversy over whether a diet high in margarine can increase LDL cholesterol to approximately the same degree as a diet high in saturated fat, and that it may also cause a reduction of good (HDL) cholesterol, the best advice here is to use margarine in moderation. Better yet, instead of using butter or margarine, you can use olive oil to lightly sprinkle your toast and vegetable oil to cook or bake. You may also baste roasted food with tomato juice, pureed vegetables or fruits, in place of oil.
Chemical Structure of Saturated and Unsaturated Fats