The Function of Lipids: An In-depth Explanation of These Fats

We often associate the term "lipids" with the term "fats." In some ways that association is correct, in others it's wrong. The evil that comes from defining the term "lipids" as "fats" is that we tend to think of fats as bad things. Thus lipids are bad, and really they aren't bad at all. While lipids are classified as a group of "fats," not all lipids are fats; and all lipids perform essential body functions. In fact, we need lipids to survive and function on a normal everyday basis. Perhaps instead of group defining the term "lipids" we should more closely at what exactly it is that lipids do within the body.

There are several different forms of lipids in the body, and each serve a specific and very important purpose. The first group of lipids is a group devoted to the storage of energy. When we think energy we often think carbohydrates, and while it is true that carbohydrates provide energy for the body, it is the lipids which play an essential role in storing that energy for a later time. Lipids are able to store more energy per gram of their mass than carbohydrates and protein. (Ophardt, 2003). Without lipids, we wouldn't have enough energy to do more than an hour of activity!

Aside from storing energy, lipids also form the membrane of body cells. The membrane, also known as the plasma membrane, is made up of a bilayer of lipids. This lipid layer serves as a means of keeping bad things from entering the cell and is what is referred to as "semi-permeable," which means it can select what enter and what doesn't. Additionally, the lipid bilayer membrane serves to hold the cell together and keep organelles safely inside the cell. Additionally, the cell membrane serves to recognize necessary enzymes, transports food sources into the cell, and contains specific sites for hormone recognition. (Purves, Sadava, Orians, and Heller, 2001).