There is only one kind of cholesterol, and it does far more good than harm. When the popular press refers to "good" and "bad" cholesterol, it is actually referring to droplets in the blood called lipoproteins, which are a complex of cholesterol, fat, phospholipids, and protein. So-called bad cholesterol refers to low-density lipoprotein (LDL), which has a high ratio of lipid to protein and contributes to cardiovascular disease. So-called good cholesterol refers to high-density lipoprotein (HDL), which has a lower ratio of lipid to protein and may help to prevent cardiovascular disease. Even when food products are advertised as cholesterol-free, they may be high in saturated fat, which stimulates the body to produce more cholesterol. Palmitic acid seems to be the greatest culprit in stimulating elevated cholesterol levels, while linoleic acid has a cholesterol-lowering effect. Both are shown in figure 2.19. Cardiovascular disease is further discussed at the end of chapter 19, and LDLs and HDLs are more fully explained in chapter 26.
Table 2.7 Some Lipid Functions
Figure 2.21 A Prostaglandin. This is a modified fatty acid with five of its carbon atoms arranged in a ring.
Fatty acids Triglycerides
Eicosanoids Fat-soluble vitamins
Steroid hormones Bile acids
Precursor of triglycerides; source of energy
Energy storage; thermal insulation; filling space; binding organs together; cushioning organs
Major component of cell membranes; aid in fat digestion
Chemical messengers between cells Involved in a variety of functions including blood clotting, wound healing, vision, and calcium absorption
Component of cell membranes; precursor of other steroids
Chemical messengers between cells Steroids that aid in fat digestion and nutrient absorption
Saladin: Anatomy & I 2. The Chemistry of Life I Text I I © The McGraw-Hill
Physiology: The Unity of Companies, 2003 Form and Function, Third Edition
Was this article helpful?
Discover secrets, myths, truths, lies and strategies for dealing effectively with cholesterol, now and forever! Uncover techniques, remedies and alternative for lowering your cholesterol quickly and significantly in just ONE MONTH! Find insights into the screenings, meanings and numbers involved in lowering cholesterol and the implications, consideration it has for your lifestyle and future!