nnaise in Two Minutes or Less”
Author: J. Kenji López-Alt
Published on Aug 12, 2016
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Sterols have a very different structure from triglycerides and phospholipids. Most sterols do not contain any fatty acids but rather multi-ring structures. They are complex molecules that contain interlinking rings of carbon atoms, with side chains of carbon, hydrogen, and oxygen attached. Cholesterol is the best-known sterol because of its role in heart disease. It forms a large part of the plaque that narrows the arteries in atherosclerosis. In stark contrast, cholesterol does have specific beneficial functions to perform in the body. Like phospholipids, cholesterol is present in all body cells as it is an important substance in cell membrane structure. Approximately 25 percent of the cholesterol in the body is localized in brain tissue. Cholesterol is used in the body to make a number of important things, including vitamin D, glucocorticoids, and sex hormones, progesterone, testosterone, and estrogens. Notably, the sterols found in plants resemble cholesterol in structure. However, plant sterols inhibit cholesterol absorption in the human body, which can contribute to lower cholesterol levels.
Although cholesterol is preceded by its infamous reputation, it is clearly a vital substance in the body that poses a concern only when there is an excess accumulation of it in the blood. The body synthesizes the majority of the cholesterol present in our body
- Three fatty acids combine with one glycerol to make a triglyceride, the body’s storage form of fat.
- The carbon chain in fatty acids can be saturated (filled with hydrogen), monounsaturated (with one point of unsaturation and possessing one carbon-carbon double bond), or polyunsaturated (with more than one point of unsaturation and possessing two or more double-carbon bonds)
- The structure and length of a fatty acid determine whether it is solid or liquid at room temperature.
- Essential fatty acids cannot be synthesized by the body and must be included in the diet. Omega-3 and omega-6 fatty acids have opposing functions and must be consumed in proper balance to promote health.
- Fatty acids in food influence the composition of fatty acids in the body.
- Phospholipids are diglycerides with a phosphate-nitrogen group in place of the third fatty-acid chain. They are ideal emulsifiers as they keep oil and water mixed.
- Sterols contain a multi-ring structure. Cholesterol serves important body functions such as vitamin D and hormone synthesis and is important in the cell membrane and brain structure.
- List the oils, snacks, spreads, or sauces in your home. Do they contain saturated or unsaturated fatty acids?
- Name the characteristic that differentiates a triglyceride from a phospholipid. Describe the properties of phospholipids. Discuss their role in forming cell membranes. Explain their role as an emulsifier.
- Think about your favorite restaurant and the food you like to order there. What type of fatty acids does a typical meal that you eat there have? Discuss the health benefits and possible drawbacks. What foods would you add to enhance your meal? What foods should you consider avoiding?
- Consider ways you could substitute saturated fats for unsaturated fats in your diet. Give specific examples.