Fats and Cholesterol in Health

1. Fats and Cholesterol in Health Unit 18

2. Changing Views about Fat • Type of fat is more important than total fat • Excess calories cause weight gain, not fat • Healthy diets provide 20-35% of calories from “healthy” fats

3. Facts about Fats • Fats are a subcategory of lipids • Lipids • Compounds that are insoluble in water and soluble in fat • Includes triglycerides, saturated and unsaturated fats, oils, cholesterol, and essential fatty acids

4. Key Terms • Essential fatty acids • Components of fats required in the diet • Linoleic and alpha-linolenic acids

5. Functions of Dietary Fats • Energy source • 9 calories/gram • Carriers of fat-soluble nutrients • Essential fatty acids • Fat soluble vitamins (D,E,K,A)

6. Energy stores Excess calories are converted to triglycerides 1 pound body fat ~ 3500 calories Functions of Dietary Fats

7. Cushion and protect internal organs Provide insulation against cold Functions of Dietary Fats

8. Functions of Dietary Fats • Increase flavor and palatability of food • Contribute to the sensation of feeling full • Components of cell membranes, vitamin D, and sex hormones

9. Functions of Dietary Fats

10. There are many types of fat in food and in our bodies Varieties of Fats

11. Varieties of Fats

12. Make up 98% of our fat intake and most of our body’s fat store Transported in blood attached to protein carriers Used for energy and tissue maintenance Triglycerides

13. Saturated and Unsaturated Fats • Saturated fats • Carbon chains saturated with the maximum number of hydrogen atoms (all single bonds) • Solid at room temperature • Found in animal products • Unsaturated fats • Monounsaturated: One double bond • Polyunsaturated: Two or more double bonds

14. Saturated and Unsaturated Fats

15. Fat Profiles of Foods

16. Essential Fatty Acids • Linoleic acid • Omega-6 fatty acid • Component of all cell membranes, especially in nerves and brain • Required for growth, skin, reproductive system • Factor in regulation of blood pressure, clotting • In sunflower, safflower, corn, and soybean oils

17. Essential Fatty Acids • Alpha-linolenic acid • Omega-3 fatty acid • Component of all cell membranes, especially in nerves and brain • Has opposite effects of linoleic acid on regulation of blood pressure and clotting • In walnuts, dark green leafy vegetables, flaxseed, canola, and soybean oils

18. Other Omega-3 Fatty Acids • EPA (eicosapentaenoic acid) • Precursor of compounds used for blood clotting and blood pressure regulation • Limits damage from inflammatory and oxidative reactions • DHA (docosahexaenoic acid) • Needed for brain and eye formation

19. EPA and DHA • EPA and DHA are found in fish and shellfish • Adequate intake for adults: 500mg/day • 8 oz fatty fish (2 meals) per week • Reduces risk of heart disease and stroke • Improves fetal development • Limit fish oil supplements to 2 grams/day

20. EPA and DHA in Seafoods

21. EPA and DHA Fortified Foods • Fish oils are now added to many foods and animal feeds • In juices, dairy, eggs, meat • Confirm that foods contain EPA and DHA • Sources of omega-3s other than fish oils do not contain EPA and DHA

22. Hydrogenated Fats • Hydrogenation is used to transform unsaturated fats into saturated fats • Turns liquid oils into solid fats • Extends shelf life of processed foods • Hydrogenation • Addition of hydrogen to unsaturated fatty acids • Converts natural cis form into trans fat

23. Cis Fatty Acids • Cis fatty acids • The most common, naturally-occurring form of unsaturated fatty acid • Contain hydrogens located on the same side of doubly-bonded carbons

24. Trans Fatty Acids • Trans fatty acids • Unsaturated fatty acids in fats that contain atoms of hydrogen attached to opposite sides of carbon atoms joined by a double bond • Trans fats • Fats containing fatty acids in the trans form

25. Trans and Cis Fatty Acids

26. Trans Fats • Trans fats produced by hydrogenation: • Raise blood cholesterol levels more than any other type of fat • Increase risk of heart disease, stroke, sudden death from heart disease, type 2 diabetes • As little as 2.2 grams/day increases risk • Trans fat content required on labels

27. Trans Fats in Foods

28. Trans Fats on Labels

29. Cholesterol is found only in animal products Checking Out Cholesterol

30. 2/3 of cholesterol is produced by the liver The rest is obtained from the diet Sources of Cholesterol

31. Contributions of Cholesterol • Cholesterol: • Is found in all cell membranes • Is a major component of nerves and brain • Is needed to produce estrogen, testosterone, and vitamin D • Cannot be used for energy

32. Finding Fat Content of Food • Where fat contents of foods are listed: • Food composition tables, Diet Analysis Plus Program software, nutrition labels on foods • To calculate % of calories from fat: • Grams fat x 9 calories/gram = fat calories • Fat calories/total calories x 100 = % of total calories from fat

33. Fat Labeling • Food labels must specify fat, saturated fat, trans fat, and cholesterol content • Any claims must adhere to standard definitions for “low fat” or “fat-free”

34. Cholesterol Claims

35. Changes in Recommendations • New recommendations have been developed for intakes of fat and cholesterol • Diets relatively high in “good” fats reduce risk of heart disease, stroke, obesity

36. High in “good” fats Reduces risk of stroke and heart disease Mediterranean Diet

37. “Good” Fats, “Bad” Fats • “Bad” fats • Include trans fats, saturated fats, cholesterol • Elevate total cholesterol and LDL levels • Solid at room temperature (fats) • “Good” fats • Lower total cholesterol and LDL levels • Raise HDL levels • Liquid at room temperature (oils)

38. “Good” Fats, “Bad” Fats

39. Current Recommendations • Adults: 20-35% of total calories from fat • AIs • Linoleic acid: 5 g/day (men), 12 g/day (women) • Α-linolenic acid: 1.6 g/day (men), 1.1 g/day (women)

40. Current Recommendations • Trans fat and saturated fat intake: • As low as possible with a nutritious diet • Cholesterol: < 200 mg/day • EPA and DHA • Increase consumption by eating fish