Nutr 132 Chapter 4 Boyle St
- 1. Chapter 4: The Lipids Presented by Michelle Loy, MPH, MS, RD
- 2. Learning Objectives At the completion of this section, the students will be able to: Describe the functions of triglycerides, phospholipids, and cholesterol. Differentiate the 3 types of fatty acids Define trans fats and explain their effect on human health Outline the steps involved in fat digestion, absorption, and transportation
- 3. Discuss the roles of fats in the body and in food Discuss the relationship between lipids and health (cardiovascular disease, cancer, obesity) Review a diet and suggest modifications so that it would meet current recommendations for the types and amounts of fat. Learning Objectives
- 4. Define the types of essential fatty acids and their functions Differentiate between visible and invisible fats in food Identify major sources of saturated, monounsaturated, polyunsaturated, omega-6, omega-3, and trans fatty acids and cholesterol in the diet. Learning Objectives
- 6. Types of Lipids -- Triglycerides Most commonly found in food and in body storage Properties determined by fatty acids they contain
- 7. Saturated vs Unsaturated Fatty acids
- 8. Different Unsaturated Fatty Acids: Essential Fatty Acids Must be consumed in the diet Linoleic acid ( -6) and alpha-linolenic acid ( -3)
- 9. Different Unsaturated Fatty Acids The hydrogen atoms at the unsaturated region can be arranged in different positions: Cis Trans Hydrogenation
- 10. Foods Contain Varying Amounts of Fatty Acids
- 11. Types of Lipids -- Key role in structure of cell membranes Manufactured in our bodies so they are not required in our diet
- 12. Types of Lipids -- Cholesterol: Made only by animals in the liver Component of cell membrane and myelin Needed for synthesis of vitamin D, bile, and some hormones
- 13. Plant sterols and stanols Naturally found in some vegetable oils, nuts, seeds, legumes, grain products, fruits, and vegetables Have been added to common foods Help lower LDL-cholesterol 2-3 g/d of plant sterols or stanols Types of Lipids --
- 15. Roles of fats in the body Energy Insulation Nerve cell transmissions
- 16. Roles of fat in food Nutrient Transport Appetite Flavor and texture
- 17. Recommendations The Acceptable Macronutrient Distribution Range (AMDR) for fat: _________% of calories should be from fat Cholesterol <_____ mg/d for a healthy adult population <200 mg/d for adults with elevated blood LDL-cholesterol levels
- 18. Recommendations The type of fat consumed is important. Saturated fat should be no more than ___% of total calories. Trans fatty acids should be reduced to the absolute minimum . Most fat in our diets should be from monounsaturated fats.
- 19. Dietary Guidelines When selecting and preparing meat, poultry, dry beans, and milk or milk products, make choices that are lean, low-fat, or fat-free. Limit intake of fats and oils high in saturated and/or trans fatty acids, and choose products low in such fats and oils Recommendations
- 20. Mostly found in animal products Fatty cuts of meat Poultry with skin Lard Whole milk dairy products (whole or 2% milk, yogurt, cheese, ice cream) Butter Tropical oils (palm, palm kernel, coconut) Food Sources of Fat
- 21. Food Sources of Fat Found in greatest amounts in food from plants Olive, canola, sunflower, peanut oils Olives Nuts Avocados Found in great amounts in food from plants Safflower, canola, sunflower, corn, soybean, flaxseed, and cottonseed oil Nuts
- 22. Major sources of trans fats in the diet
- 23. EPA and DHA Seafood – fatty, coldwater fish Salmon, mackerel, herring 12-14 oz of fish/week ALA Flaxseeds, flaxseed oil Walnuts Soybean and canola oil (small amount) Food Sources of Fat
- 24. Food Sources of Fat Dietary cholesterol Only found in animal foods Sources Egg yolk, beef, poultry, cheese, milk, shellfish, organ meat
- 25. Food Sources of Fat Fats we can see in our foods or knowingly add to foods Fats hidden in foods Naturally occurring or added during processing
- 26. Lipids and Health Too little fat: Essential fatty acid deficiency Too much total fat and too much “bad” fat Cardiovascular disease Cancer Obesity
- 27. Dietary Fat and Heart Disease Buildup of fatty material in the artery walls cause atherosclerosis
- 28. Risk factors for cardiovascular disease
- 29. Cardiovascular Disease Blood lipids include Triglycerides Chylomicrons VLDLs – very low-density lipoproteins LDLs – low-density lipoproteins “ bad cholesterol” HDLs – high-density lipoproteins “ good cholesterol”
- 30. Dietary Factors That Promote Heart Disease Dietary Cholesterol Gene-dependent Increases LDL cholesterol in the blood Increases blood LDL cholesterol levels Lower HDL cholesterol levels Excess Energy Increases body fat
- 31. Dietary Factors That Protect Against Heart Disease -6 fatty acids Lower both LDL and HDL cholesterol -3 fatty acids Lower LDL cholesterol Other benefits Monounsaturated fat Decrease LDL cholesterol Plant foods Fiber and antioxidants B vitamins Decrease blood homocysteine level Moderate alcohol consumption
- 32. Dietary Fat and Cancer Diets high in fat and low in fiber and plant foods are correlated with the incidence of cancer. Breast cancer Colon cancer
- 33. Dietary Fat and Obesity A high-fat meal contains more kcalories than a low-fat meal of the same volume. Energy from fat is less satiating than energy from carbohydrates. It takes less energy for the body to use fat as an energy source. However , fat content is unlikely the reason for the high obesity rate in the U.S.
- 34. Reasons to keep fat intake low Diets lower in fat are generally lower in calories and thereby help achieve and maintain healthy body weight Diets low in saturated and trans fats reduce the risk of heart disease Diets lower in fat, particularly saturated fat, may lower the risks of some cancers Diets with fewer calories from fat have more room for health promoting foods
- 35. Translating recommendations into healthy diets Read food labels Choose added fats carefully Limit amounts Choose healthier fats Choose protein sources wisely Substitute low-fat ingredients for high-fat ingredients in recipes Choose leaner cooking methods Choose smaller portions of higher fat items Reduce frequency of consumption of higher fat items Increase vegetables and fruits
- 36. How to Choose Fats Wisely
- 37. Assignment On at least one day this week: Incorporate at least 1 source of healthy fat Reduce at least 1 source of unhealthy fat