Balancing Your Saturated Fats & Unsaturated Fats
What do a stick of butter and a bottle of olive oil have in common? They’re both fat and provide 9 calories per gram or 252 calories per ounce – about 85 calories per tablespoon. But olive oil is much better for you than butter.
Most animal fat, for example butter or the white fat around beef, is solid at room temperature. In contrast, vegetable fat, more specifically vegetable oil, is liquid at room temperature. It’s obvious why nutritionists call animal fat “hard fat” and vegetable oil “soft fat.”
Saturated and unsaturated fats differ in their chemical structure. The terms saturated and unsaturated refer specifically to their chemical structure or molecular configuration. Chemists tell us the structure of highly saturated or hard fat is dense and uniform because the molecular linkages holding the carbon atoms together are all used up. In contrast, vegetable oils are not dense and uniform. The linkages holding their carbon atoms together are not used up. The spaces in their molecular structure are open and reactive. When you see “hydrogenated vegetable oil” on a label, it means hydrogen was added to those open spaces, which turns the oil into a solid fat. Olive oil, a monounsaturated fatty acid (MFA), is an excellent example of an oil that has only one open space. MFA oils are liquid at room temperature, tend to be amber in color, and are somewhat thick or moderately viscous.
Beef lard is a saturated fatty acid (SFA). SFAs are not liquid at room temperature; they are white and hard. This is true of most animal fat.
Sunflower oil is a polyunsaturated fatty acid (PUFA) – an oil that has many open spaces. PUFA oils vary in their degree of saturation. The more unsaturated they are, the lighter in color and the more fluid they are. Some are nearly as clear as water.
PUFAs help keep blood pressure normal. In fact, some of these oils can help reduce blood pressure. Vegetable oil supplies linoleic acid, a plant oil essential for health. Linoleic acid is the raw material for prostaglandin number 2 (PG2), a substance the body produces. PG2 and other materials produced from it are important in the relaxation and contraction of the muscles that line the arterioles. Therefore, linoleic acid has a metabolic effect that helps to maintain normal blood pressure.
PUFAs also reduce blood pressure by reducing blood viscosity. Remember that reduced viscosity decreases total peripheral resistance to blood flow, and decreased resistance means lower blood pressure.
Saturated fats have a tendency to increase blood pressure by increasing blood viscosity. Increased viscosity contributes to total peripheral resistance, and that increases blood pressure. Obviously, the dietary objective should be to reduce saturated fat; emphasize the unsaturated fat in the diet; and obtain sufficient amounts of a special PUFA, called the omega-3 oils, from fish and vegetable sources. These changes are achieved by shifting emphasis from meat and butter to foods that contain unsaturated fats.