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Lipids

Lipids. Socialgather.org. Lipid Hypothesis. The lipid hypothesis states that fats are the cause of many disease processes: Coronary Heart Disease Cardiovascular Disease. Because of this untested hypothesis, lipids have been vilified as a food to be avoided or eaten in great moderation

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Lipids

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  1. Lipids • Socialgather.org

  2. Lipid Hypothesis • The lipid hypothesis states that fats are the cause of many disease processes: • Coronary Heart Disease • Cardiovascular Disease

  3. Because of this untested hypothesis, lipids have been vilified as a food to be avoided or eaten in great moderation The next slide depicts the old food pyramid, determine where it addresses lipids and the differences between recommended lipid intake versus carbohydrate intake

  4. Lipids

  5. Artificial Fat Replacer

  6. Olestra

  7. Olestra Structure • Olestra is a sucrose molecule with 8 fatty acids attached to it • We do not have enzymes that can break these chemical bonds • Therefore it cannot be digested • It is a no calorie fat replacer

  8. Advantages • Because it has fatty acids in it’s structure, texturally it feels like fat • Because we cannot digest it, it has no caloric value

  9. Disadvantages • It can trap fat soluble vitamins and cause deficiencies • It can make the feces very oily, which can lead to spontaneous anal leakage • It can cause gas, cramping and bloating

  10. Lipid Types to Discuss • Fatty Acids: energy fat 9C/g • Triglycerides: energy fat 9C/g • Sterols: structural fat • Phospholipids: structural fat

  11. Energy Fats • Energy fats are considered potential energy • We store this fat in specialized cells within the body • These cells are called adipocytes • They are unique in that we can create more but once we have them, they will not go away…we cannot reduce their # • All we can do is fill and empty them

  12. Adipocytes • University of Illinois

  13. Fatty Acid Structure

  14. Fatty Acids • Long carbon chain molecules with attached hydrogen ions • Each carbon has the 4 bonding sites • In a fatty acid, the C can bind to either another C or an H

  15. Types of Fatty Acids • Saturated Fatty Acid • Monounsaturated Fatty Acid (MUFA) • Polyunsaturated Fatty Acid (PUFA) • Trans Fatty Acid (TFA)

  16. Saturated Fatty Acids 10% • Carry maximal hydrogen • Long chain fatty acid: solid at room temp. • Short chain saturated fats: liquid at room temp. (e.g., coconut oil)

  17. Saturated Fatty Acid

  18. Monounsaturated Fats 10% • Has 1 C=C • Short chain fatty acids = what physical characteristic? • CaproleicAcid • Lauroleic Acid • Myristoleic Acid • Palmoteic Acid • Oleic Acid (Omega 9) • Eruric Acid (Omega 9)

  19. Monounsaturated Fatty Acid • Library.med@utah.edu

  20. Omega 9 Fatty Acids • Terminal double bond at 9 carbon • Not considered essential • b/c no n6 bond….does not promote eicosanoids • Olive oil, canola, rapeseed, mustard oil

  21. Polyunsaturated Fats • Library.med.utah.edu

  22. Polyunsaturated Fats 10% • 2 or more C=C • Contain Essential PUFAs: • Omega 3 • Omega 6

  23. Omega 3 • Alpha Linolenic Acid n-3 • Sources: soybean oil, canola oil, walnuts, wheat germ, flax, fishes, chia, hemp seeds, algaes, leaves • Converted by liver into : • Eicosapantaenic Acid • Docoshexanoic Acid

  24. Functions • Neurological development • Reduce vascular disease • Reduce tumor growth • Reduce inflammation • Reduce CVD • Improved immune function • Cell structure

  25. Omega 6 • Linoleic Acid n-6 • Sources: most vegetable oil, nuts, seeds • Converted by the liver: • Arachidoic Acid • Docosopantanoic Acid

  26. Functions • Promotes dermal integrity • Visual health • Cell structure

  27. Problems Associated • Proinflammatory • Eicosanoid: • Leukotrienes: inflammation • Thromboxane: platelet aggregation • Prostanglandins: immune and inflammation response

  28. Diseases Associated • CVD • CHD • Cancer • Artherosclerosis • Alzheimers • Obesity • Diabetes • ADHD • Stroke • Arthritis • Osteoporosis • ETC!!!

  29. TransFatty Acid (TFA)

  30. Structural Comparison • Trans position • Rigid • Cis-position • Fluid

  31. Naturally Occurring TFA • Ruminants and their lactation: • CLA (conjugated linoleic acid) • Vaccenic Acid • 3-7% total fat

  32. Artificially Occurring • Partial Hydrogenation of Unsaturated Fats • Process was created in 1901 • Proctor and Gamble created Crisco in 1911

  33. Benefits • Increased shelf life • Decreased refrigeration • Lower cost than tallow, palm oil, coconut oil or palm kernel oil (saturated fats) • Solid at room temp. and liquid when heated

  34. Dangers • Promotes increased Coronary Heart Disease (1956) and Cardiovascular Disease by increasing LDL and decreasing HDL • New England Journal of Medicine • National Academy of Science

  35. Recommendations • Non-essential and dangerous…the NAS recommends that we receive ZERO TFA • Labeling: to be ZERO TFA, a product must contain less that 1gr/serving

  36. Triglyceride Structure

  37. Structural Fats Phospholipids and Cholesterol

  38. Phospholipid Structure

  39. Phospholipid Function • We utilize phospholipids in all of our cell (plasma) membranes • It allows cells to selectively determine what enters and exits the cell

  40. LIPID BILAYER

  41. Sterols • Sterols are ring stuctures that we use in many molecules in our bodies • Functionally they create steroids, fat-soluble hormones and are a structural component of our brain and nerves • R.D.A. is no more than 300mg/day

  42. Cholesterol

  43. Fat Digestion

  44. Mouth • Mechanical Digestion • Food mixes with saliva via mastication=bolus • Chemical Digestion: • Lingual Lipase: begins to melt triglycerides

  45. Stomach • Mechanical Digestion: creation of chyme • Chemical Digestion: • Gastric Lipase: acts upon butterfats and other triglycerides

  46. Small Intestines • Chyme squirted into SI • NaHCO3 neutralizeschyme • Bile emulsifies fat into micelles • Pancreatic lipase converts triglycerides into diglycerides • Intestinal lipase converts diglyceridesinotmonoglycerides and fatty acids

  47. Intestinal Mucosa • Absorbs fatty acids and monoglycerides and anabolically makes triglycerides • Absorbs cholesterol and phospholipid • Combines these fats into a chylomicron • Goes to the liver

  48. Liver • Dismantles the exogenous chylomicron • Creates VLDL • Released into bloodstream • VLDL becomes LDL

  49. LDL • High concentration of cholesterol • Attach to cellular cholesterol receptors and release cholesterol in cells • Do this to arterial cells…leads to plaques • Returned to liver to be destroyed

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