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Lipids

Lipids. The Good, the Bad and the Truly Ugly!. Lipids. Organic molecules most of which do not dissolve in water. Fats & oils Types of lipids: Fatty acids Glycerides Phospholipids sterols. Fatty Acids. Carbon chains Methyl, acid groups Degree of saturation

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Lipids

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  1. Lipids The Good, the Bad and the Truly Ugly!

  2. Lipids • Organic molecules most of which do not dissolve in water. • Fats & oils • Types of lipids: • Fatty acids • Glycerides • Phospholipids • sterols

  3. Fatty Acids • Carbon chains • Methyl, acid groups • Degree of saturation • Location of first double bond

  4. Types of Fatty Acids

  5. Glycerides The major form of lipid in food and in the body

  6. Phospholipid Lecithin, a common food additive, is a phospholipid. Embedded in cell membranes.

  7. Sterols • Cholesterol: • 90% is found in cell membranes • Produced by the liver • Associated with cardiovascular disease • Produced by animals only. None found in plants.

  8. Fats in the Diet • Typically meats, dairy products, & other animal products are the main source of saturated fatty acids. • Palm, coconut oils are high in saturated fats. • Unsaturated fatty acids tend to come from plant oils: olive, canola, peanut , safflower, sunflower, corn; also fish, nuts

  9. Fats in the Diet

  10. Unsaturated Fats in the Diet Omega-6- Omeg-3- The Good!

  11. Hydrogenated Fats • Hydrogenation of vegetable oils converts some of unsaturated bonds to saturated, trans conformation. • Trans fatty acids extend shelf life, improve margarine, shortening. • Diet high in trans fatty acids risks heart disease, cancer.

  12. Trans Fatty Acids The Truly Awful!

  13. Function of Lipids • Immediate source of energy • Stored form of energy (85% triglycerides) • Protection and cushioning • Eye sockets, heart valves, kidneys, fatty apron • Insulation (temperature regulation)

  14. Adipose Tissue Fat stored in this cell

  15. Fat Storage

  16. Another view….

  17. Fat Storage Area

  18. When there is a bit much…. Abdominoplasty Before After

  19. Function continued • Structural part of cell membranes (phospholipids, cholesterol) • Regulation • Cell communication, neurotransmitter synthesis • Bile salts (from cholesterol), • Hormones (from cholesterol) • Prostaglandins, eicosanoids (from omega-3 & omega-6 fatty acids)

  20. Fat Packed on Heart

  21. How you store fat….and then release it

  22. Essential Fatty Acids • Linoleic, alpha-linolenic acid are essential • Deficiency • Rare because requirement is low • Symptoms: scaly, dry skin, liver abnormalities, poor healing of wounds, growth failure, impaired vision and hearing • Observed in infants, young children fed low-fat diets, adults consuming a weight-loss diet of only nonfat milk

  23. Reduced Fat Foods • Variety of reduced fat and free fat foods are available. • Designed to mimic taste, texture of fat • Low fat may mean low fiber, vit., minerals • Low fat foods are not always low in kcal • In many foods, fats are replaced with other energy-containing nutrients • Regular brownie has 112 kcal; reduced fat brownie has 89 kcal

  24. Low Fat Diet • A diet low in fat & high in simple sugars increases blood triglyceride levels & may increase the risk of heart disease. May increase risk of diabetes. • May not be a healthy diet. • Snacks of fresh fruits instead of these would be much better.

  25. Types of Artificial Fats • Carbohydrate-based fat substitutes • Pectins, gums mimic texture of fat • Oatrim, Nutrim add soluble fiber • Protein-based fat substitutes • Simplesse is fat substitute made from egg white, milk proteins • Used in frozen desserts, cheese foods; 1.3 cal/g • Poorly absorbed fats as fat substitutes • Caprenin consists of glcerol with 3 poorly absorbed fatty acids attached; 5kcal/g • Olestra has fatty acids attached to sucrose; cannot be digested; no absorption

  26. The Good!

  27. The Bad!

  28. The Truly Awful!

  29. The Consequences of Poor Choices! The Ugly

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