Polyunsaturated fat

Alternative names

Saturated fat; Diet - fat; Fat; Monounsaturated fat; Lipids

Definition

Fats are organic compounds that are made up of carbon, hydrogen, and oxygen; they are the most concentrated source of energy in foods. Fats belong to a group of substances called lipids. Fats come in liquid or solid form. All fats are combinations of saturated and unsaturated fatty acids. Fats can be called very saturated or very unsaturated depending on their proportions.

Function

Fat is one of the three nutrients (along with protein and carbohydrates) that supply calories to the body. Fat provides 9 calories per gram, more than twice the number provided by carbohydrates or protein.

Fat is essential for the proper functioning of the body. Fats provide the "essential" fatty acids, which are not made by the body and must be obtained from food. Linoleic acid is the most important essential fatty acid, especially for the growth and development of infants. Fatty acids provide the raw materials that help in the control of blood pressure, blood clotting, inflammation, and other body functions.

Fat serves as the storage substance for the body's extra calories. It fills the fat cells (adipose tissue) that help insulate the body. Fats are also an important energy source. When the body has used up the calories from carbohydrate, which occurs after the first 20 minutes of exercise, it begins to depend on the calories from fat.

Healthy skin and hair are maintained by fat. Fat helps in the absorption, and transport through the bloodstream of the fat-soluble vitamins A, D, E, and K.

Food Sources

• Saturated fats: These are the biggest dietary cause of high LDL levels ("bad cholesterol"). When looking at a food label, pay very close attention to the % of saturated fat and avoid or limit any foods that are high (for example, over 20% saturated fat). Saturated fats are found in animal products such as butter, cheese, whole milk, ice cream, cream, and fatty meats. They are also found in some vegetable oils - coconut, palm, and palm kernel oils. (Note: most other vegetable oils contain unsaturated fat and are healthy.)
  
• Unsaturated fats: Fats that help to lower blood cholesterol if used in place of saturated fats. However, unsaturated fats have a lot of calories, so you still need to limit them. There are two types: mono-unsaturated and polyunsaturated. Most (but not all!) liquid vegetable oils are unsaturated. (The exceptions include coconut, palm, and palm kernel oils.)
  
• Mono-unsaturated fats: Fats that help to lower blood cholesterol if used in place of saturated fats. However, mono-unsaturated fats have a lot of calories, so you still need to limit them. Examples include olive and canola oils.