What Are Some Types of Lipids?

The term "lipid" groups together all naturally occurring fat-soluble molecules, such as triglycerides--also known as fats and oils--as well as phospholipids and sterols. The majority of lipids found in foods are fats and oils.

Function

• Lipids are a concentrated energy source, containing nearly twice the amount of energy per gram than protein or carbohydrates. Lipids also carry fat-soluble vitamins in the body, and are involved with many bodily functions, such as insulating the body from temperatures changes in the environment and prolonging the digestive process.

Triglycerides

• Important for fat metabolism and the production of energy, triglycerides are composed of three fatty acids: saturated fatty acids, unsaturated fatty acids including monounsaturated and polyunsaturated fatty acids, and hydrogenated fatty acids. Polyunsaturated acids provide the body with essential nutrients it cannot manufacture on its own. Saturated and hydrogenated fatty acids, however, raise cholesterol levels and increase an individual's risk for heart disease.

Phospholipids

• Phospholipids, also known as phosphatides, are fat derivatives and the main part of cell membranes. Phospholipids also assist in regulating the cell environment.

Sterols

• Sternols are an important group within the broader classification of steroids. They are the essential component of a plant membrane and can be found in grains, fruits, nuts, seeds, vegetables and vegetable oils.

Olestra

• Olestra is part lipid but also part carbohydrate and is sometimes used as a fat substitute in "low-fat" or "fat-free" processed foods and diet products.