LIPIDS

1. LIPIDS

2. Lipids • Triglycerides • fats and oils • Phospholipids • Sterol derivatives

3. Storage • Adipose tissue Fat storing Can expand indefinitely by number by size Lipids

4. Lipids • Provides energy • stored fat supplies 60% of energy during rest • prolonged exercise • starvation

5. Lipids • Provide insulation • vital organ protection • nerve impulse transmission • Cell structure • Enhance fat soluble vitamin absorption

6. Lipids • Facilitate weight gain • Found in plants and animals • Visible and invisible (hidden) fats • Body synthesizes all fatty acids except two • 9 kcal/g

7. Lipids • Supply taste and flavor to foods • Post-prandial satiety • Can stay 3 - 4 hours in stomach

8. Lipids • Precursor for synthesis of steroid hormones • prostalandins and actylcholine

9. Triglycerides • Fats and oils • 95% of total fat intake • 3 fatty acids attached to 3 carbon based glycerol • Glycerol is an alcohol • Straight chains • C2 to C20+

11. Fatty Acids • Differ in two ways • Chain length • short- not usually in foods • medium- milk fat, non-dairy creamers • long- meat fats, olive oil, peanut oil • very long- fish oils, some plant oils

12. Fatty Acids • Degree of saturation • Partially determines health impact • Chemical structure • saturated-all single bonds • monounsaturated-one double bond • polyunsaturated-two or more double bonds

13. Linoleic Plant oils Omega 6 Rare deficiency Hormone-like Part of clotting process and immune response Linolenic Fish oils Omega 3 Rare deficiency Hormone-like Part of clotting process and immune response Essential Fatty Acids

14. In the news Research on preventing heart disease Fish oil supplements? Eat the fish! Too much fish oil acts a blood thinner. Dark meat fish or cold water fish. Bass, cod, salmon Linolenic -Omega 3

15. Phospholipids • Glycerol with 2 fatty acids plus choline or similar compound • Lecithin • Supplement not needed • Enough made in liver • Emulsifiers • Major part of cell membrane

16. Phospholipid formed 2 fatty acids & 1 choline

17. Sterols • Cholesterol • Vitamin D • Sex hormones • Adrenocortical hormones

18. Plant sterols • Poorly absorbed • Compete with CHOL absorption • Can decrease CHOL absorption up to 50% • Subject of research & TV ads • Phytoestrogens-hot topic in women’s health

19. Sterols • Cholesterol • made in liver, not essential • part of cell membranes • precursor of bile acids • helps vitamin D be formed • part of hormones

20. Cholesterol • Bile is made from cholesterol • stored in gall bladder • prepares fat for digestion • after fat digestion,some is excreted and some is reabsorbed • CHOL in reabsorbed bile is reused • Medications and dietary fiber is used to bind bile-reduces total CHOL

21. Cholesterol • Some travels in bloodstream as part of lipoproteins • Can become trapped in arteries and contribute to heart disease • High CHOL and high fat diet increased risk of LDL elevation

22. Dietary Fat • Excessive intakes • =obesity • =diabetes mellitus • =cancer • =heart disease

23. Obesity • Imbalance • Too many kcal in • Not enough energy expenditure • Percentage of fat in diet varies • Do not restrict fat until age 2 • Gradually change diet to match dietary guidelines during childhood

24. Cancer • Fat may promote, but does not cause cancer • High fat diets linked to increased risk for • Colon and rectum • Prostate • Endometrium • More research needed

25. Cardiovascular Disease • Leading cause of death • Plaque development causes increased incidence of blood clots • Strongest diet connection • Too much saturated fat in the diet • Polyunsaturated fats have both +/- effects • Monounsaturated fats more beneficial

26. Saturated Fat • Associated with serum CHOL elevation • Main dietary determinant of blood CHOL levels • Omega 3 fatty acids reduce CHOL most • delay cancer development?

27. Polyunsaturated Fat • Associated with total serum CHOL reduction • Reduction LDL-C • Shorter chained, unsaturated fats are softer and melt more easily. • Lard is hard.

28. Monounsaturated Fat • Associated with serum TG reduction • Maintenance of HDL-C • Serum CHOL neutral

29. Fat substitutes • Instead of, not in addition • Long term health effects not known • Simplesse • Olestra • Oatrim

30. Sources • Meats, nuts, seeds, olives, avocados • Ice cream • Bakery products • Salad dressing • Milk • Fried foods

31. Hydrogenated Fats • Unsaturated vegetable oils • Hydrogen bonds have been added • More stable products • More solid products

32. Trans and CIS fatty acids • CIS fatty acid-naturally occurring bond H2 on same side of chain • Trans fatty acid-commercially made bond H2 on opposite sides • makes more solid texture • research says too much will raise serum lipid levels • limit to 5-10% of fat

33. Kcal and Grams • Kcal from fat confusing for many persons • Count fat grams • 20-30% of kcal from fat usually appropriate • X number of kcal by percent of kcal from fat wanted • Divide by 9

34. Dietary guidelines • Total fat <30% • Saturated fat <10% • Polyunsaturated <10% • Monounsaturated <10% • CHOL <300 mg • New TLC diet: 200 mg CHOL, up to 35% fat if mostly monounsaturated