Nutr 132 Chapter 4 Boyle St


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Nutr 132 Chapter 4 Boyle St

  1. 1. Chapter 4: The Lipids Presented by Michelle Loy, MPH, MS, RD
  2. 2. Learning Objectives <ul><li>At the completion of this section, the students will be able to: </li></ul><ul><ul><li>Describe the functions of triglycerides, phospholipids, and cholesterol. </li></ul></ul><ul><ul><li>Differentiate the 3 types of fatty acids </li></ul></ul><ul><ul><li>Define trans fats and explain their effect on human health </li></ul></ul><ul><ul><li>Outline the steps involved in fat digestion, absorption, and transportation </li></ul></ul>
  3. 3. <ul><ul><li>Discuss the roles of fats in the body and in food </li></ul></ul><ul><ul><li>Discuss the relationship between lipids and health (cardiovascular disease, cancer, obesity) </li></ul></ul><ul><ul><li>Review a diet and suggest modifications so that it would meet current recommendations for the types and amounts of fat. </li></ul></ul>Learning Objectives
  4. 4. <ul><ul><li>Define the types of essential fatty acids and their functions </li></ul></ul><ul><ul><li>Differentiate between visible and invisible fats in food </li></ul></ul><ul><ul><li>Identify major sources of saturated, monounsaturated, polyunsaturated, omega-6, omega-3, and trans fatty acids and cholesterol in the diet. </li></ul></ul>Learning Objectives
  5. 5. What Are Fats?
  6. 6. Types of Lipids -- Triglycerides <ul><li>Most commonly found in food and in body storage </li></ul><ul><li>Properties determined by fatty acids they contain </li></ul>
  7. 7. Saturated vs Unsaturated Fatty acids
  8. 8. Different Unsaturated Fatty Acids: Essential Fatty Acids <ul><li>Must be consumed in the diet </li></ul><ul><ul><li>Linoleic acid (  -6) and alpha-linolenic acid (  -3) </li></ul></ul>
  9. 9. Different Unsaturated Fatty Acids <ul><li>The hydrogen atoms at the unsaturated region can be arranged in different positions: </li></ul><ul><ul><li>Cis </li></ul></ul><ul><ul><li>Trans </li></ul></ul><ul><li>Hydrogenation </li></ul>
  10. 10. Foods Contain Varying Amounts of Fatty Acids
  11. 11. Types of Lipids -- <ul><li>Key role in structure of cell membranes </li></ul><ul><li>Manufactured in our bodies so they are not required in our diet </li></ul>
  12. 12. Types of Lipids -- <ul><li>Cholesterol: </li></ul><ul><ul><li>Made only by animals in the liver </li></ul></ul><ul><ul><li>Component of cell membrane and myelin </li></ul></ul><ul><ul><li>Needed for synthesis of vitamin D, bile, and some hormones </li></ul></ul>
  13. 13. <ul><li>Plant sterols and stanols </li></ul><ul><ul><li>Naturally found in some vegetable oils, nuts, seeds, legumes, grain products, fruits, and vegetables </li></ul></ul><ul><ul><li>Have been added to common foods </li></ul></ul><ul><ul><li>Help lower LDL-cholesterol </li></ul></ul><ul><ul><ul><li>2-3 g/d of plant sterols or stanols </li></ul></ul></ul>Types of Lipids --
  14. 14. Digestion of Fats
  15. 15. Roles of fats in the body <ul><li>Energy </li></ul><ul><li>Insulation </li></ul><ul><li>Nerve cell transmissions </li></ul>
  16. 16. Roles of fat in food <ul><li>Nutrient </li></ul><ul><li>Transport </li></ul><ul><li>Appetite </li></ul><ul><li>Flavor and texture </li></ul>
  17. 17. Recommendations <ul><li>The Acceptable Macronutrient Distribution Range (AMDR) for fat: </li></ul><ul><ul><li>_________% of calories should be from fat </li></ul></ul><ul><li>Cholesterol <_____ mg/d for a healthy adult population </li></ul><ul><ul><li><200 mg/d for adults with elevated blood LDL-cholesterol levels </li></ul></ul>
  18. 18. Recommendations <ul><li>The type of fat consumed is important. </li></ul><ul><ul><li>Saturated fat should be no more than ___% of total calories. </li></ul></ul><ul><ul><li>Trans fatty acids should be reduced to the absolute minimum . </li></ul></ul><ul><ul><li>Most fat in our diets should be from monounsaturated fats. </li></ul></ul>
  19. 19. <ul><li>Dietary Guidelines </li></ul><ul><ul><li>When selecting and preparing meat, poultry, dry beans, and milk or milk products, make choices that are lean, low-fat, or fat-free. </li></ul></ul><ul><ul><li>Limit intake of fats and oils high in saturated and/or trans fatty acids, and choose products low in such fats and oils </li></ul></ul>Recommendations
  20. 20. <ul><ul><li>Mostly found in animal products </li></ul></ul><ul><ul><ul><li>Fatty cuts of meat </li></ul></ul></ul><ul><ul><ul><li>Poultry with skin </li></ul></ul></ul><ul><ul><ul><li>Lard </li></ul></ul></ul><ul><ul><ul><li>Whole milk dairy products (whole or 2% milk, yogurt, cheese, ice cream) </li></ul></ul></ul><ul><ul><ul><li>Butter </li></ul></ul></ul><ul><ul><ul><li>Tropical oils (palm, palm kernel, coconut) </li></ul></ul></ul>Food Sources of Fat
  21. 21. Food Sources of Fat <ul><ul><li>Found in greatest amounts in food from plants </li></ul></ul><ul><ul><ul><li>Olive, canola, sunflower, peanut oils </li></ul></ul></ul><ul><ul><ul><li>Olives </li></ul></ul></ul><ul><ul><ul><li>Nuts </li></ul></ul></ul><ul><ul><ul><li>Avocados </li></ul></ul></ul><ul><ul><li>Found in great amounts in food from plants </li></ul></ul><ul><ul><ul><li>Safflower, canola, sunflower, corn, soybean, flaxseed, and cottonseed oil </li></ul></ul></ul><ul><ul><ul><li>Nuts </li></ul></ul></ul>
  22. 22. Major sources of trans fats in the diet
  23. 23. <ul><ul><li>EPA and DHA </li></ul></ul><ul><ul><ul><li>Seafood – fatty, coldwater fish </li></ul></ul></ul><ul><ul><ul><ul><li>Salmon, mackerel, herring </li></ul></ul></ul></ul><ul><ul><ul><ul><li>12-14 oz of fish/week </li></ul></ul></ul></ul><ul><ul><li>ALA </li></ul></ul><ul><ul><ul><li>Flaxseeds, flaxseed oil </li></ul></ul></ul><ul><ul><ul><li>Walnuts </li></ul></ul></ul><ul><ul><ul><li>Soybean and canola oil (small amount) </li></ul></ul></ul>Food Sources of Fat
  24. 24. Food Sources of Fat <ul><li>Dietary cholesterol </li></ul><ul><ul><li>Only found in animal foods </li></ul></ul><ul><ul><li>Sources </li></ul></ul><ul><ul><ul><li>Egg yolk, beef, poultry, cheese, milk, shellfish, organ meat </li></ul></ul></ul>
  25. 25. Food Sources of Fat <ul><ul><li>Fats we can see in our foods or knowingly add to foods </li></ul></ul><ul><ul><li>Fats hidden in foods </li></ul></ul><ul><ul><li>Naturally occurring or added during processing </li></ul></ul>
  26. 26. Lipids and Health <ul><li>Too little fat: </li></ul><ul><li>Essential fatty acid deficiency </li></ul><ul><li>Too much total fat and too much “bad” fat </li></ul><ul><ul><li>Cardiovascular disease </li></ul></ul><ul><ul><li>Cancer </li></ul></ul><ul><ul><li>Obesity </li></ul></ul>
  27. 27. Dietary Fat and Heart Disease <ul><li>Buildup of fatty material in the artery walls cause atherosclerosis </li></ul>
  28. 28. Risk factors for cardiovascular disease
  29. 29. Cardiovascular Disease <ul><li>Blood lipids include </li></ul><ul><ul><li>Triglycerides </li></ul></ul><ul><ul><li>Chylomicrons </li></ul></ul><ul><ul><li>VLDLs – very low-density lipoproteins </li></ul></ul><ul><ul><li>LDLs – low-density lipoproteins </li></ul></ul><ul><ul><ul><li>“ bad cholesterol” </li></ul></ul></ul><ul><ul><li>HDLs – high-density lipoproteins </li></ul></ul><ul><ul><ul><li>“ good cholesterol” </li></ul></ul></ul>
  30. 30. Dietary Factors That Promote Heart Disease <ul><li>Dietary Cholesterol </li></ul><ul><ul><li>Gene-dependent </li></ul></ul><ul><ul><li>Increases LDL cholesterol in the blood </li></ul></ul><ul><ul><li>Increases blood LDL cholesterol levels </li></ul></ul><ul><ul><li>Lower HDL cholesterol levels </li></ul></ul><ul><li>Excess Energy </li></ul><ul><ul><li>Increases body fat </li></ul></ul>
  31. 31. Dietary Factors That Protect Against Heart Disease <ul><li> -6 fatty acids </li></ul><ul><ul><li>Lower both LDL and HDL cholesterol </li></ul></ul><ul><li> -3 fatty acids </li></ul><ul><ul><li>Lower LDL cholesterol </li></ul></ul><ul><ul><li>Other benefits </li></ul></ul><ul><li>Monounsaturated fat </li></ul><ul><ul><li>Decrease LDL cholesterol </li></ul></ul><ul><li>Plant foods </li></ul><ul><ul><li>Fiber and antioxidants </li></ul></ul><ul><li>B vitamins </li></ul><ul><ul><li>Decrease blood homocysteine level </li></ul></ul><ul><li>Moderate alcohol consumption </li></ul>
  32. 32. Dietary Fat and Cancer <ul><li>Diets high in fat and low in fiber and plant foods are correlated with the incidence of cancer. </li></ul><ul><ul><li>Breast cancer </li></ul></ul><ul><ul><li>Colon cancer </li></ul></ul>
  33. 33. Dietary Fat and Obesity <ul><li>A high-fat meal contains more kcalories than a low-fat meal of the same volume. </li></ul><ul><li>Energy from fat is less satiating than energy from carbohydrates. </li></ul><ul><li>It takes less energy for the body to use fat as an energy source. </li></ul><ul><li>However , fat content is unlikely the reason for the high obesity rate in the U.S. </li></ul>
  34. 34. Reasons to keep fat intake low <ul><li>Diets lower in fat are generally lower in calories and thereby help achieve and maintain healthy body weight </li></ul><ul><li>Diets low in saturated and trans fats reduce the risk of heart disease </li></ul><ul><li>Diets lower in fat, particularly saturated fat, may lower the risks of some cancers </li></ul><ul><li>Diets with fewer calories from fat have more room for health promoting foods </li></ul>
  35. 35. Translating recommendations into healthy diets <ul><li>Read food labels </li></ul><ul><li>Choose added fats carefully </li></ul><ul><ul><li>Limit amounts </li></ul></ul><ul><ul><li>Choose healthier fats </li></ul></ul><ul><li>Choose protein sources wisely </li></ul><ul><li>Substitute low-fat ingredients for high-fat ingredients in recipes </li></ul><ul><li>Choose leaner cooking methods </li></ul><ul><li>Choose smaller portions of higher fat items </li></ul><ul><li>Reduce frequency of consumption of higher fat items </li></ul><ul><li>Increase vegetables and fruits </li></ul>
  36. 36. How to Choose Fats Wisely
  37. 37. Assignment <ul><li>On at least one day this week: </li></ul><ul><ul><li>Incorporate at least 1 source of healthy fat </li></ul></ul><ul><ul><li>Reduce at least 1 source of unhealthy fat </li></ul></ul>