List three classes of lipids found in the body and in foods. Describe the features that fats bring to foods. Discuss their functions in the body.
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What is the role of bile in fat digestion? Define the term emulsifier.
Emulsifier: substance that helps water-soluble and water-insoluble compounds mix with each other
Where is cholesterol found in the diet? Do we get calories from cholesterol?
Although triglycerides are widespread in foods, cholesterol is found only in animal foods. Egg yolk, liver, meat, poultry, whole milk, cheese, and ice cream are rich sources of cholesterol. Cholesterol is a sterol, a more chemically complex type of lipid
What types of fats have the most negative effect on blood lipids?
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Describe features that distinguish fatty acids from each other. Which fatty acid has one double bond? What determines a lipid's degree of saturation?
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Define "omega" with respect to fatty acids. Describe the roles of the omega fatty acids in disease prevention.
Cannot be made by the body!
- Linoleic Acid and the Omega-6 Family
� Can make arachidonic acid, which is a
conditionally essential fatty acid
� Supplied by vegetable oils and meats
- Linolenic Acid and the Omega-3 Family
� Must be supplied by food
� Can m
Compare the differences between saturated, trans, unsaturated, monounsaturated, and polyunsaturated fats and know food sources of each.
A saturated fatty acid has each carbon within the fatty acid chain completely fi lled with hydrogen atoms. An unsaturated fatty acid has two neighboring carbons within the chain that are missing two hydrogen atoms. Monounsaturated fatty acids have one dou
Describe the structure of a triglyceride, diglyceride, and monoglyceride.
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Describe the process of hydrogenation and what it does to fat. Define trans-fatty acids and discuss how they influence heart disease. How do we find trans fats on a food label?
Most of the trans fat in processed food results from the hydrogenation process. Partial hydrogenation is a food manufacturing process that adds hydrogen atoms to some unsaturated fatty acids in liquid vegetable oil. The hydrogenation process also converts
Compare the differences between the structures of phospholipids and triglycerides. Compare these structures to the structure of cholesterol. Discuss how these differences in structure affect function.
Phospholipids have a choline or other phosphorus-containing acid in place of one of the fatty acids enabling them to function as emulsifiers in the body. The phospholipid allows the fatty acids to dissolve in water. Cholesterol is a sterol, and its C, H,
Identify the steps in fat digestion, absorption, and transport. Describe the routes cholesterol takes in the body. What part of the GI tract is the site of dietary fat hydrolysis?
Lipid digestion and absorption. Pancreatic lipase and bile facilitate lipid digestion. After lipids enter absorptive cells of the small intestine, triglycerides are re-formed. Triglycerides and other lipids are coated with a layer of protein, phospholipid
Describe the functions of lipoproteins. Compare the differences between the chylomicrons, VLDL, LDL, and HDL.
Composed of triglycerides, cholesterol, phospholipids, and proteins, lipoproteins transport lipids in the body. Chylomicrons are the largest of the lipoproteins, formed in the intestinal wall following fat absorption, and they contain mostly triglycerides
What are the normal levels for HDL, LDL, TG and total cholesterol in the blood?
� Desirable levels:
-Total cholesterol < 200 mg/dL
-LDL cholesterol < 100 mg/dL
-HDL cholesterol ? 60 mg/dL
-Triglycerides < 150 mg/dL
List the fatty acids that are essential. Name their chief dietary sources.
� Omega
- Refers to position of the first double bond
� Omega-3 Fatty Acid
- Location of double bond in the third position
- Example is linolenic acid
� Omega-6 Fatty Acid
- Location of double bond in the sixth position
- Example is linoleic acid
Describe how excessive fat intake influences health. List factors that influence LDL, HDL, and total blood cholesterol.
Factors that lower LDL and raise HDL:
-Weight control
-Replace saturated fat with monounsaturated fat and polyunsaturated fat in the diet
-Soluble fibers
-Phytochemicals
-Moderate alcohol consumption
-Physical activity
List the dietary recommendations regarding fat and cholesterol intake. List ways to reduce intake.
� DRI: 20% - 35% of energy intake
� Daily Values
- 65 g fat based on 30% of 2000-kcal diet
- 20 g saturated fat based on 10% of 2000-kcal
diet
- 300 mg cholesterol
� USDA Food Guide considers saturated fats
discretionary kcalories.
� Too little fat can be
Calculate the Daily Value for fat (based on a 2,000 kcalorie diet). Describe what this number represents.
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What foods and oils are highest in monounsaturated fats? Polyunsaturated fats? Saturated fats? Trans fats?
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Where do we get omega-3 fats and omega-6 fats in the diet?
The body cannot synthesize two polyunsaturated fatty acids, alpha-linolenic acid and linoleic acid. These lipids are essential fatty acids because they must be supplied by the diet. Alpha-linolenic acid is an omega-3 fatty acid. The "3" refers to the posi
How are fats digested and absorbed?
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A meal providing 900 kcal contains 8g saturated fat, 10g monounsaturated fatty acids (MUFA), 15g polyunsaturated fatty acids (PUFA). What is the percent of energy supplied by lipids?
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What is olestra? Are there any drawbacks?
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What is the macronutrient distribution range for fat intake?
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What percentage of kcals should come from saturated fats? Total fat?
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