Module 5: Lipids Objectives Flashcards
Describe the three types of lipids.
Lipids include triacylglycerols, phospholipids, and sterols; triacylglycerols are the most common lipid in food and in the body.
Compare and contrast the structure of the following types of fats:
- triacylglycerols (including saturated, monounsaturated, polyunsaturated, cis, trans, omega-3, and omega-6 fatty acids)
- phospholipids
- sterols
-Triacylglycerols (also known as triglycerides) make up more than 95 percent of lipids in the diet and are commonly found in fried foods, vegetable oil, butter, whole milk, cheese, cream cheese, and some meats. The most common type of fat in the body, composed of one glycerol molecule and three fatty acid molecules. (Also called Triglycerides.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).
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.
-Phospholipids are lipids that have a glycerol backbone attached to two fatty acids and a phosphate group.They are emulsifiers that are amphiphilic (likes and dislikes water) Bind together to form cell membranes and allow transport of water and fat through the membrane.Phospholipids are diglycerides with a phosphate group in place of the third fatty-acid chain.
Sterols are the least common type of lipid. Cholesterol is the most well know and common sterol in the diet. It is produced by the body and animal fats from the diet. Since the body makes it, it is not essential to get it from diet. Cholesterol is an important component of the cell membrane and is required for the synthesis of sex hormones, vitamin D, and bile salts.Sterols have a very different structure from triacylglycerols and phospholipids. Most sterols do not contain any fatty acids but rather are 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. Although cholesterol has a bad reputation when it comes to heart health, it is a vital substance in the body that poses a concern only when there is excess accumulation of it in the blood.
Summarize the steps in lipid digestion and absorption.
In the stomach fat is separated from other food substances. In the small intestines bile emulsifies fats while enzymes digest them. The intestinal cells absorb the fats.
Explain how lipids are used for energy and stored in the body.
When the body has used all of its calories from carbohydrates (which can occur after just twenty minutes of exercise), it initiates fat usage. A professional swimmer must consume large amounts of food energy to meet the demands of swimming long distances, so eating fat-rich foods makes sense. In contrast, if a person who leads a sedentary lifestyle eats the same fat-rich foods, they will likely get more fat calories than their body requires. Excess energy from food is stored as adipose tissue in the body.
List and describe functions of lipids in the human body.
Fats within the body are critical for storing energy, maintaining body temperature, cushioning vital organs, regulating hormones, transmitting nerve impulses, and transporting fat-soluble nutrients.
List and describe the role of lipids in food.
Fats in food provide a condensed energy source, enhance the texture and flavor of food, and promote satiety.
Describe the current recommended intake levels for lipids.
The recommended fat intake for adults is 20–35% of your total caloric intake. Saturated fat should be less than 10% of your total caloric intake and trans fat should be less than 1% of total caloric intake.
Recognize sources of saturated, trans, unsaturated, and essential fatty acids.
Saturated Fat animal products, dairy products, palm and coconut oils, and cocoa butter
Trans Fat stick/tub margarines, fast foods, commercial baked goods, some snack foods
Cholesterol animal products, liver, eggs, dairy products
Monounsaturated Fat nuts (almonds, cashews, pecans, peanuts, and walnuts) and nut products, avocados, extra virgin olive oil, sesame oil, high oleic safflower oil, sunflower oil, and canola oil
Polyunsaturated Fat nuts (walnuts, hazelnuts, pecans, almonds, and peanuts), soybean oil, corn oil, safflower oil, flaxseed oil, canola oil, and fish (trout, herring, and salmon)
Essential Fatty Acids
Omega-3 Fatty Acids (alpha-linolenic acid) canola oil, flaxseed oil, soybean oil, olive oil, nuts, seeds, whole grains, legumes, green leafy vegetables, cod liver oil, and fatty fish (tuna, herring, mackerel, salmon, and trout)
Omega-6 Fatty Acids (linoleic acid) eggs, poultry, most vegetable oils, wheat germ oil, whole grains, baked goods, cereals, nuts and seeds (flaxseeds, sunflower seeds, sesame seeds)
Compare and contrast the roles of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) in your body.
LDL, or “bad” cholesterol, has low protein composition and high cholesterol content. High levels of LDL have been shown to increase the risks for heart disease.
HDL or “good’’ cholesterol has a larger proportion of protein and a small cholesterol composition. HDL scavenges excess cholesterol and returns it to the liver for reuse or disposal. A high level of HDL reduces the risk for heart disease.
Identify healthy blood lipid profile ranges.
Cholesterol less than 200
LDL less than 100 (optimal)
HDL 60 or higher (considered protective)
