Module 5 - Lipids or Fats - Spring 2020 Notes PDF

Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Lipids Learning Objectives 1. List the categories of lipids. 2. Describe the basic structure of a fatty acid. 3....

Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Lipids Learning Objectives 1. List the categories of lipids. 2. Describe the basic structure of a fatty acid. 3. Compare and contrast the structures of saturated, monounsaturated, polyunsaturated, cis, and trans fatty acids. 4. List common dietary sources of saturated, unsaturated, and trans fatty acids and cholesterol. 5. Describe the effects of saturation on the physical state of fatty acids at room temperature. 1 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Learning Objectives 6. Identify the two essential fatty acids and common dietary sources of each. 7. List the functions of lipids in the body and in foods. 8. Identify the kcal per gram and AMDR for lipids. 9. List 3 types of fat substitutes used in food products. 10. Discuss the side effects taking fat blockers for weight loss Learning Objectives 11. Define atherosclerosis, ischemia, myocardial infarction, stroke, and cardiovascular disease. 12. Identify the type of lipid carried by each of the four lipoproteins. 13. Discuss the functions of LDL and HDL and their impact on heart disease. 14. List the diet and lifestyle recommendations to reduce risk of heart disease. 15. Explain the Dietary Guidelines for Americans 2015 recommendations on fat intake. 2 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Learning Objectives 16. Compare and contrast the Mediterranean diet to the typical Western diet. 17. Discuss the link between dietary fat intake and chronic diseases. The lipids in our food and our bodies Fats, or the scientific term, lipids, are defined as o substances that are soluble in organic solvents (i.e. ether, acetone and chloroform) 3 major categories of lipids : o Triglycerides o Phospholipids o Sterols (ex: cholesterol) 3 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 The lipids in our food and our bodies Lipids are composed of the same elements that are contained in carbohydrates: Carbon (C) Hydrogen (H) Oxygen (O) Difference between lipid and carbohydrate composition? Fatty acids Fatty acid is a chain of carbons linked together. The chain has a carboxyl group on one end and a methyl group on the other The carboxyl group (COOH) hydrophilic The methyl group (CH3) hydrophobic Fatty acids are components in phospholipids triglycerides 4 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Fatty acid saturation refersto whether carbon chain is occupied by all of the hydrogen atoms it can hold If carbon chain is fully occupied by hydrogen atoms, then it is a saturated fatty acid. unsaturated fatty acids fatty acid with one or more double bonds 1. monounsaturated fatty acid fatty acid with one double bond 2. polyunsaturated fatty acid fatty acid with two or more double bonds Fatty acids 1. Saturated solid at room temp. 2. Monounsaturated liquid at room temp. 3. Polyunsaturated liquid at room temp. 5 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Fatty acids in common foods linolenic acid Essential and nonessential fatty acids essential fatty acids cannot be made by the body must be provided in the diet They are in two families of fatty acids: 1. Omega-6 linoleic acid 2. Omega-3 linolenic acid 6 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Omega-3 and Omega-6 fatty acids (linoleic acid) Omega-3 and Omega-6 fatty acids Omega-6 Omega-3 incorporated into cell membranes in cell membranes precursors to compounds involved help prevent tissue inflammation in reproduction and blood flow Eicosapentanoic acid (EPA) ex: arachidonic acid Docosahexanoic acid (DHA) may help prevent heart disease and blood clot formation 7 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Trans fatty acids Hydrogenation: Process of adding hydrogens to unsaturated fats Makes solid at room temp. Common dietary sources store-bought cakes, cookies and crackers; margarine; shortening Trans fatty acid (man-made/synthetic): produced through addition of hydrogen atoms to double bonds of fatty acids Small amount of naturally occurring trans fatty acids are found in: dairy milk and meat 8 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Trans fatty acids Cis vs. Trans fatty acids Only some unsaturated fats converted to saturated fats via hydrogenation: Partially hydrogenated Trans fatty acids Dietary trans fatty acids from hydrogenation are associated with: increased levels of “bad” or low-density lipoprotein (LDL) reduced levels of “good” or high-density lipoprotein (HDL) increased risk for heart disease The American Heart Association recommends 2 g of trans fatty acids per day or less < 1% of total calories 9 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Triglyceride Simply stated, a triglyceride is a chemical structure composed of: A three-carbon glycerol backbone Three fatty acids Primary form of lipid found in food and in the body The fatty acids in triglycerides found in the body often reflect dietary fatty acids consumed. Phospholipid phospholipids compounds that assist the body in transporting fat through watery substance Chemically similar to triglycerides Three-carbon glycerol backbone Two fatty acids bound to first two carbons Third carbon has phosphate group bound to it 10 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Phospholipids Phosphate group changes properties of the structure: Phosphate head is hydrophilic Fatty acid tail is hydrophobic Phospholipids function as emulsifiers blending of water and fat components In the body, phospholipids are important component of Cell membrane Lipoproteins transport particles for fats in body Sterols/Cholesterol These groups of lipids are quite different chemically from the other lipids Four-rings Includes cholesterol Sterols are vital to health and basic metabolic functions Examples testosterone estrogen Vitamin D 11 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Sterols/Cholesterol Liver makes most of the cholesterol our bodies contain. Cholesterol is not essential The American Heart Association recommends that dietary cholesterol be kept below 300 mg a day for healthy persons: thought to be associated with heart disease risk the more likely problem: dietary saturated and trans fat LIPIDS FUNCTIONS OF LIPIDS IN THE BODY 12 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Lipid functions Energy source Stored form Primary energy source for heart Concentrated energy source 9 kcal/g fat vs. 4 kcal/g protein or carbohydrate One tablespoon vegetable oil ~120 calories 13 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Supply of essential fatty acids Two essential fatty acids: linoleic acid linolenic acid Both are precursors to eicosanoids that have powerful physiological effects in the body relaxing blood vessels and promoting clotting Absorption and transport of fat-soluble vitamins Fat is required for the absorption of fat-soluble vitamins Vitamins A, D, E and K Fat-soluble vitamin absorption decreases when there is incomplete fat absorption or fat malabsorption. 14 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Organ insulation and protection Fat has an important function in protecting and insulating the vital organs of the body Example: fat deposits located around kidney The fat layer under the skin can also contribute to the insulating effects of fat. Gender differences in body fat composition females have greater % body fat than males Picture source: http://www.britannica.com/science/cell-membrane Cell membrane structure Phospholipids and cholesterol are major components of cell and organelle membranes 15 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Precursor to steroid hormones Cholesterol serves an important role in the body as the precursor to many hormones: estrogen testosterone aldosterone Cholesterol is also a precursor to a fat soluble vitamin that has hormone-like functions: Vitamin D Sensory quality of food and human satiety The role of fat in foods: mouthfeel texture flavor compounds interact with fat molecules in food Fat causes you to feel full longer satiety fat slows stomach emptying enhances flavor compounds dietary fat and weight management? 16 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Primary Sources of Fat in the Human Diet Saturated fatty acids Beef, pork, poultry with skin and other meats Cheese, butter, and other dairy products Palm and coconut oils (tropical oils) Unsaturated fatty acids Vegetable oils Nuts and seeds Fish Cholesterol Only found in animal products Nutrient Content Claims Requirement Fat free < 0.5 g fat per serving Low fat ≤ 3 g fat per serving Light 50% less fat than regular product Saturated fat free < 0.5 g saturated fat and < 0.5 g trans fat per serving Trans-fat free < 0.5 g trans fat per serving Cholesterol free < 2 mg cholesterol and ≤ 2g sat. fat per serving Lean < 10 g fat, 4.5 g sat. fat, and 95 mg cholesterol per 100 g serving (meat, poultry and seafood) 17 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Fat Replacers Fat mimetics 1. Carbohydrate-based Add creaminess, bulkiness, and moistness maltodextrins, modified food starches, cellulose, and gums 1-4 kcal per gram 2. Protein-based denature under high heat used in frozen desserts 4 kcal per gram Fat Replacers Fat substitute 3. Fat-based Non-digestible/partially digested Contribute to taste, texture, and mouthfeel Ex: Olean (Olestra), Salatrim, Caprenin Side effects o reduced vitamin A, D, E and K absorption o loose stools o abdominal cramps 18 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Fat Blockers Marketed as weight loss drugs o Alli® - over-the-counter oXenical, Orlistat - prescription o disrupt intestinal fat absorption inhibit digestive enzyme that breaks down triglycerides Side effects: o anal leakage o reduced fat soluble vitamin A, D, E & K absorption o malabsorption of oral contraceptives LIPIDS LIPIDS AND HEALTH 19 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Heart Disease Leading cause of death in U.S. men and women Modifiable risk factors high blood pressure high cholesterol cigarette smoking diabetes poor diet and physical inactivity overweight and obese Heart Disease Risk and Diet Risk by excess consumption of nutrients that raise blood cholesterol o total fat o saturated fat o trans fat Dietary cholesterol has less significant impact on blood cholesterol level. 20 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Cardiovascular Diseases Primary type of heart disease linked with fat intake is atherosclerosis o Build up of fatty deposits and streaks in the arteries May reduce blood flow to areas of the heart causing ischemia. Artery becomes completely blocked: myocardial infarction or heart attack Stroke: blockage of artery supplying blood to brain Lipoproteins Lipoproteins are spherical structures that are composed of lipids and proteins. Transport lipid particles in body Outer shell is monolayer o proteins o phospholipids What property of these molecules allow them to transport lipids in the body? 21 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Lipoproteins Lipoproteins The blood contains four types of lipoproteins. 1. Chylomicrons 2. VLDLs 3. LDLs 4. HDLs Chylomicrons o made in cells of small intestine otransport dietary lipids to the liver Very low-density lipoproteins (VLDLs) o synthesized in the liver o contain both triglycerides and cholesterol o deliver triglycerides to other tissues 22 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Lipoproteins Low-density lipoproteins (LDLs) oformed after VLDLs deposit triglycerides in other tissues ocholesterol rich odeliver cholesterol to other tissues, including blood vessels “Bad Cholesterol” High-density lipoproteins (HDLs) omade mostly in the liver, but also in the small intestine oremoves excess cholesterol from cells oreturn to liver for elimination “Good Cholesterol” Functions of Lipoproteins 23 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Recommendations for Dietary Intake of Fats USDA’s 2015 Dietary Guidelines for Americans o 20 - 35% of daily calories from fat ofat intake below range not recommended decreased absorption of fat-soluble vitamins Childrenunder age 2 o 30–35 % calories from fat o growth and nervous system development depend on adequate fat intake Recommendations for Dietary Intake of Fats Saturated fat ≤ 10 % of total calories o replace with: polyunsaturated and monounsaturated fatty acids Minimize trans fat and products with hydrogenated fat Found in: Crackers Snack foods Ready made cakes, cookies Margarine, shortening 24 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Recommendations for Dietary Intake of Fats Consume less: o high fat meat, pork, lamb, poultry with skin on o cheese and whole fat dairy o processed meats o butter, margarine Consume more: o fruits, vegetables, whole grains o nuts, seeds o low fat or non-fat dairy o liquid vegetable oils o lean meat, pork, lamb, poultry without skin and fatty fish Other recommendations to reduce heart disease risk Physicalactivity o 150 min. of moderate or 75 min. of vigorous activity each week Maintain or attain a healthy weight Stop smoking Alcohol in moderation o 1-2 drinks for males daily o 1 drink for females daily 25 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Mediterranean Diet Pyramid Obesity Is the obesity epidemic in the United States and other industrialized nations connected with an increased fat intake? % of calories from fats in our diet has decreased over the last two decades. Low fat diets may promote weight loss. Those who follow Mediterranean Diet are generally less obese. o diet is not lower fat o ~35% of calories from fat 26 Rebecca A Creasy, PhD, NSCA-CPT 02/03/2020 NFSC 202 Cancer Inconclusiveevidence regarding diets high in total calories from fat and cancer incidence Type of fatty acids consumed influences cancer risk o High levels of saturated fat linked to incidence breast, ovarian, colon and prostate cancers o Consumption of fatty fish and fish oil high in omega-3 fatty acids associated with incidence colon, breast, lung, esophageal, skin and pancreatic cancers 27