Ch. 5 The Lipids Flashcards
Define the following: lipid, triglyceride, phospholipid, and sterol.
Lipid: family of compounds that include triglycerides (TG), phospholipids, and sterols (cholesterol).
TG: the chief form of fat in the diet and the major storage form of fat in the body
Phospholipids: a compound similar to a triglyceride but having a phosphate group and choline in place of one of the fatty acids.
Sterol (cholesterol): compounds containing a four-ring carbon structure with any of a variety of side chains attached.
List the functions of TG in the diet.
Provide source of essential fatty acids (FA).
Provide fat soluble vitamins (A, B, & K).
Furnish concentrated energy source.
Deliver flavor, texture, tenderness.
Add satiety.
List the role of TG in the body.
Padding.
Store concentrated energy source.
Discuss the structure of a TG. What is it comprised of? How much do TG contributed the fat intake of a typical American individual?
1 Tg = glycerol + 3 fatty acids (FA) –> saturated or monounsaturated or polyunsaturated.
Contribute to majority of fat intake.
List and describe the 3 types of fatty acids found in foods. What are they? How are they relate to TG?
Monounsaturated fat: a fatty acid that lacks two hydrogen atoms and has one double bond between carbons.
Polyunsaturated fat: a fatty acid that lacks four or more hydrogen atoms and has two or more double bonds between carbons.
Saturated fat: a fatty acid carrying the maximum possible number of hydrogen atoms.
Relation to TG: they’re the 3 FA that make up TG
What are the structural differences between saturated and unsaturated fatty acids? What effect do saturated and unsaturated fatty acids have on heart health?
Saturated fat: a fatty acid carrying the maximum possible number of hydrogen atoms.
Unsaturated fat: a fatty acid that lacks hydrogen atoms and has at least one double bond between carbons (includes monounsaturated and polyunsaturated fatty acids).
Saturated fats are worse for heart health than unsaturated fats. Using unsaturated fats instead of saturated reduces LDL cholesterol and lowers the risk of heart disease.
What are examples of saturated, monounsaturated, and polyunsaturated fats?
Saturated fats: butter, lard (pork fat), coconut oil, beef fat, chicken fat.
Monounsaturated fats: olive oil, canola oil, peanut oil
Polyunsaturated fats: corn oil, sunflower oil, safflower oil, soybean oil, cottonseed oil, walnut oil, fish oil, flaxseed oil.
What is hydrogenation? Why is hydrogenation used? What are the dietary sources?
Def: adding Hydrogen to mono or polyunsaturated fatty acids –> reduces the number of double bonds –> becomes more saturated.
Why: makes more resistant to oxidation (prolongs shelf life), makes more solid texture.
Dietary sources: margarine, shortening, pudding (makes pudding creamier)
What are the essential fatty acids and why are they called essential?
Def: fatty acids needed by the body but not made by it in amounts sufficient to meet physiological needs.
–Linoleic Acid [Omega-6]
–Linolenic Acid [Omega-3]
What are omega-3 and omega-6 fatty acids? What are dietary sources? What effect does omega-3 have on heart health?
They’re polyunsaturated fats.
Omega-3: fatty fish (mackerel, salmon, sardines), walnuts, flaxseed.
Omega-6: vegetable oils, meats. [Generally enough in our diet]
They lower TG.
What is the most updated recommendation regarding eating fish?
Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury.
Differentiate between a cis and trans fatty acid. What are dietary sources of trans fat? What effect do trans fats have on heart health?
Cis: A natural fatty acid, in which the carbon parts lie on the same side of the double bond.
Trans: fatty acids with hydrogens on opposite sides of the double bond.
Sources of trans fat: commercial baked goods, partially hydrogenated foods, and has low levels in meat and dairy.
Heart health: increases LDL-chol (bad cholesterol), lowers HDL-chol (good cholesterol).
Describe phospholipids. What is their role in the body? What role do they play in food? What are dietary sources?
A compound similar to a triglyceride but having a phosphate group and choline in place of one of the fatty acids.
Role in body: enable transport of lipids across cell membranes, emulsifier, lecithin made by liver.
Role in food: emulsifier.
Food: eggs, liver, wheat germ, peanuts.
Describe cholesterol. Where is it found? What are dietary sources? What is the recommended limit for dietary intake of cholesterol? What is the recommended fasting blood cholesterol level?
Def: one of the sterols containing a four-ring carbon structure with a carbon side chain.
Found: produced by liver. [endogenous]
Dietary sources: meats, eggs, fish, poultry, dairy. [exogenous]
Provide recommended levels of dietary intake (using the recommendations given in class) for the following: dietary cholesterol, total fat, saturated fat.
Dietary cholesterol: Recommendations are less than 300 mg
Saturated fat: less than 10% of daily energy intake
Total fat: 20-35% of daily energy intake
