In what food source is the nutrient found?

Unsaturated fat can be either monounsaturated or polyunsaturated. These fats come mostly from plant sources and are liquid at room temperature. Foods high in monounsaturated fat include avocados, olives, and peanuts. Canola, olive, almond, hazelnut, and peanut oils are also high in this type of fat. Foods high in polyunsaturated fat include fatty fish, nuts and vegetable oils such as safflower and sunflower.

Omega-3 fatty acids are polyunsaturated fatty acids. They are found in certain cold-water fish such as salmon, mackerel, albacore tuna, sardines, and lake trout. Omega-3 fatty acids may help prevent heart disease because they lower triglycerides and reduce blood clotting. They may also lower blood pressure and prevent arrhythmias.

Trans fats are also known as trans fatty acids. They are formed when vegetable oils are processed into margarine or shortening through a process called hydrogenation. Hydrogenation makes the fat solid at room temperature. Stick margarine and vegetable shortenings are examples of hydrogenated products. Foods high in trans fatty acids include french fries, donuts, crackers, and cookies.

How does the nutrient affect the body?

Both kinds of unsaturated fat can be used in place of saturated fat in the diet. This substitution helps to lower levels of total and LDL cholesterol in the blood. All types of fat should be eaten in moderation.

The effect of monosaturated fats was studied in the DELTA Study. DELTA is short for Dietary Effects on Lipoproteins and Thrombogenic Activity. When monosaturated fats replace saturated fat in the diet, they improve cholesterol levels. They reduce triglycerides, total cholesterol, and LDL, which is also known as the bad carrier for cholesterol. They increase HDL, known as the good carrier for cholesterol.

Polyunsaturated fats supply essential fatty acids, or EFAs. The body does not make these fatty acids and must get EFAs from food. EFAs are needed for normal growth and development in children and for healthy skin. EFAs are vital to the human brain and central nervous system. They also produce hormone-like substances that help regulate blood pressure, blood clotting, and the immune system.

Trans fats raise LDL cholesterol levels and may also lower HDL cholesterol in the blood. They tend to raise total blood cholesterol levels but not as much as more saturated fatty acids.