Nutrition Science and Everyday Application - beta v 0.1

Lipid Types and Structures
Lipids are a family of organic compounds that are mostly insoluble in water, meaning
they do not mix well with water. There are three main types of lipids: triglycerides,
phospholipids, and sterols. On this page, we’ll learn about the structures of these three
types of lipids, as well as their functions in the body and where you can find them in foods.
TRIGLYCERIDES
Triglycerides are the main form of lipids in the body and in foods. More than 95 percent of
lipids in the diet are in the form of triglycerides, some having a visible presence and some
hidden in foods. Concentrated fats (butter and vegetable oil, for example) and marbling of
fat in meat are obviously visible. But fat can also be hidden in foods, as in baked goods, dairy
products like milk and cheese, and fried foods. Naturally occurring triglycerides are found in
many foods, including avocados, olives, corn, and nuts. We commonly call the triglycerides
in our food “fats” and “oils.” Fats are lipids that are solid at room temperature, whereas oils
are liquid. The terms fats, oils, and triglycerides are often used interchangeably. In this unit,
when we use the word fat, we are referring to triglycerides.
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