Discuss the functions of lipids in the body. What is the role of the liver in metabolizing and processing fats?

Question

What will be an ideal response?

Answer 1

First and foremost, triglycerides—either from food or from the body's fat stores—provide the cells with energy. When a person dances all night, her dinner's triglycerides provide some of the fuel that keeps her moving. When a person loses his appetite, his stored triglycerides fuel much of his body's work until he can eat again.

Linoleic acid is an essential fatty acid and the primary member of the omega-6 fatty acid family. When the body receives linoleic acid from the diet, it can make other members of the omega-6 family—such as the 20-carbon polyunsaturated fatty acid, arachidonic acid. Should a linoleic acid deficiency develop, arachidonic acid, and all other omega-6 fatty acids that derive from linoleic acid, would also become essential and have to be obtained from the diet. A nonessential nutrient (such as arachidonic acid) that must be supplied by the diet in special circumstances (as in a linoleic acid deficiency) is considered a conditionally essential nutrient. Normally, vegetable oils and meats supply enough omega-6 fatty acids to meet the body's needs.

Linolenic acid is an essential fatty acid and the primary member of the omega-3 fatty acid family. Like linoleic acid, linolenic acid cannot be made in the body and must be supplied by foods. Given the 18-carbon linolenic acid, the body can make small amounts of the 20- and 22-carbon members of the omega-3 family, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), respectively. These omega-3 fatty acids play critical roles in the optimal structure and function of cells. Found abundantly in the eyes and brain, the omega-3 fatty acids are essential for normal growth, visual acuity, and cognitive development. They may also play an important role in the prevention and treatment of heart disease.

The body uses the longer omega-3 and omega-6 fatty acids to make substances known as eicosanoids. Eicosanoids are a diverse group of more than 100 compounds. Sometimes described as "hormonelike," eicosanoids differ from hormones in important ways. For one, hormones are secreted in one location and travel to affect cells all over the body, whereas eicosanoids appear to affect only the cells in which they are made or nearby cells in the same localized environment. For another, hormones elicit the same response from all their tar- get cells, whereas eicosanoids often have different effects on different cells.