Fats and cholesterol are necessary for good health. Fats cushion vital organs, are used as stored energy, and serve as an insulator to preserve body heat. The body uses cholesterol to make estrogen, testosterone, vitamin D, and other vital compounds. Cholesterol is so important to our bodies, that the body can actually make all of the cholesterol it needs (about 1000 mg). Most people, however, get some cholesterol from the foods they eat. Only foods from animals, such as meats, dairy and eggs, have dietary cholesterol; plant based foods do not.
Fat and cholesterol are carried through the bloodstream in protein-covered particles called lipoproteins. Low-density lipoproteins (LDL) carry cholesterol from the liver to the rest of the body. When there is too much LDL cholesterol in the blood, it forms deposits or plaques in the artery walls. This plaque narrows the arteries and limits blood flow; heart attacks and strokes are caused when plaque breaks apart. Because of this, LDL cholesterol is often referred to as “bad” cholesterol.
High-density lipoproteins (HDL) are essentially the opposite of LDL cholesterol. High-density lipoproteins go around the body sweeping up as much cholesterol from the bloodstream and artery walls as they can and ferry it back to the liver. HDL also contains antioxidant molecules that help prevent LDL cholesterol from being changed into unhealthy lipoproteins. This is why HDL cholesterol is often referred to as “good” cholesterol.
The types of dietary fat consumed determine, to a large extent, the amount of HDL and LDL cholesterol, as well as total cholesterol in the bloodstream. Monounsaturated and polyunsaturated fats lower disease risk. Saturated and Trans fats increase the risk for disease. Foods high in “good” fats include vegetable oils, nuts, seeds, and fish. Foods high in “bad” fats include red meat, butter, cheese, ice cream, and foods made with partially hydrogenated oil. The key to a healthy diet is to choose foods that have more good fats than bad fats; choose vegetable oils instead of butter, salmon instead of steak and choose foods that don’t contain any Trans fat.