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You've heard all the terms, but what do they mean?
Polyunsaturated, Monounsaturated, Saturated,
Essential fatty acid, Trans fatty acid, Hydrogenated fatty acid,
Cholesterol, Omega-3 fatty acids, Omega-6 fatty acids
We're getting quite used to the advise to lower our dietary fat. In fact this is one of the recommendations from the National Cancer Institute and the American Cancer Society for reducing risk of cancer as well as one of the recommendations from the American Heart Association for reducing risk of heart disease.
There are many types of fats among the foods we eat. Let's take a closer look at the terminology. The dietary fats that we eat are mostly made up of different proportions of three categories of fatty acids, monounsaturated, polyunsaturated, and saturated fatty acids.
Monounsaturated fatty acids are missing a hydrogen pair giving them one double bond in their chemical structure. Olive oil, canola, and nut oils are high in monounsaturated fatty acids. Foods high in monounsaturated fatty acids are liquid at room temperature.
Polyunsaturated fatty acids are missing two or more hydrogen pairs, or have two or more double bonds in their chemical structure. Oils high in these fats are also liquid or soft at room temperature. Examples of oils high in polyunsaturated fatty acids are corn, safflower, soybean, and sunflower.
Saturated fatty acids have no double bonds and have all the hydrogen that they can hold onto, making these fats very stable. They are solid or firm at room temperature. These fatty acids come mainly from animal sources such as meat and dairy products. Non animal sources of saturated fats are coconut, palm and palm kernel oils. Generally harder and more stable fats are more saturated, such as butter, stick margarine, shortening, and the fat in cheese and meat.
Omega-3 fatty acids are types of highly polyunsaturated fatty acids. They are most abundant in cold water fish such as mackerel, salmon, albacore tuna, sardines, lake trout and many others. Canola oil, soybean oil and some nuts and seeds also contain some omega-3 fatty acids.
Omega-6 fatty acids are types of highly polyunsaturated fatty acids found abundantly in polyunsaturated vegetable oils.
Hydrogenated fats are unsaturated fats that have undergone a process to add hydrogen to their double bonds, making their chemical structure more stable. The fat becomes solid at room temperature and foods made with these fats have a longer shelf life.
Trans fatty acids are a type of fatty acid most commonly found in the diet when polyunsaturated fats are hydrogenated.
Cholesterol is not a fat, but it is a fat-like, waxy substance. There are two types of cholesterol, the type found in the body and the type found in foods. Dietary cholesterol is found only in foods of animal origin, such as eggs, meat, poultry, fish, and dairy foods. Cholesterol is part of every cell in the body and has many important functions. Serum or blood cholesterol is mainly produced by the liver, but a high saturated fat diet and a high dietary cholesterol intake can elevate blood cholesterol in some people.
Essential fatty acids are fatty acids that your body cannot make. They are required for particular metabolic processes and must be obtained from dietary sources. Linoleic acid and alpha-linolenic acid are essential fatty acids; they are both polyunsaturated fatty acids. Linoleic acid is an omega-6 fatty acid that is found in vegetable oils and from animal sources such as fish oils, meat, and milk. Alpha-linolenic acid is an omega-3 fatty acid found in fish, canola oil, leafy green vegetables, nuts, seeds, and soybeans. The essential fatty acids are adequately supplied by a varied diet.
More information about the different types of fat and what they mean to you and your food selections will follow in the next few weeks.
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