1. Fats and Cholesterol in Health
Unit 18

2. Important Facts 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 Lipids
Compounds that are insoluble in water and soluble in fat
Includes triglycerides, saturated and unsaturated fats, oils, cholesterol, and essential fatty acids

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

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

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

7. 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

8. Functions of Dietary Fats

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

10. Triglycerides
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

11. Saturated and Unsaturated Fats

12. Saturated and Unsaturated 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

13. 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

14. 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

15. 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

16. 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

17. Trans Fatty Acids Trans fatty acids Trans fats
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

18. Trans and Cis Fatty Acids

19. 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

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

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

22. Contributions of 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

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

24. “Good” Fats, “Bad” Fats “Bad” fats “Good” 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)

25. “Good” Fats, “Bad” Fats