1. Chapter 4
Lipids: Fats and Oils

2. Lipids
Fats
Oils
Cholesterol
Lecithin

3. Functions of Lipids Insulation Cushion around critical organs
Provides energy (adipose cells = compact energy storage)
Protein-sparing
Part of all cell membranes
Transport of fat-soluble vitamins
Essential fatty acids

4. In food, fat enhances: Taste Flavor Aroma Crispness Juiciness
Tenderness
Smooth texture
Creamy feeling
Feeling full

5. Triglycerides

6. Types of Fatty Acids

7. Triglycerides in Food Fruits and vegetables
Breads, cereals, rice, pasta, and grains
Dry beans and peas, nuts and seeds
Meat, poultry, fish
Dairy foods
Fats, oils, and condiments

8. 3 Types of Triglycerides
1. Saturated triglycerides (saturated fat)
ANIMAL FOODS
Cheese
Beef
Whole milk
Fats in baked goods
Butter
Margarine

9. 3 Types of Triglycerides
2. Monounsaturated Fats
Olive oil
Canola oil
Peanut oil
Margarine made with canola oil or other highly monounsaturated fat
Olive Oil

10. 3 Types of Triglycerides
Polyunsaturated Fats
Safflower oil
Corn oil
Soybean oil
Sesame oil
Sunflower oil
Nuts and seeds

11. Trans Fatty Acids
Occur naturally at low levels in meat and dairy foods.
Trans fats we eat are often due to hydrogenation of vegetable oils to make shortening, margarine, and fats for frying.
Trans fats raise blood cholesterol levels as much as saturated fat.

12. Main Contributors to Trans Fats in Diet
Cakes, cookies, pies, bread, etc. 40% of
trans fats eaten
Animal products %
Margarine %
Fried potatoes %
Potato chips, corn chips, popcorn 5%
Household shortening %

13. Essential Fatty Acids
Linoleic acid is an omega-6 fatty acid found in vegetable oils, whole grains, and vegetables.
Alpha-linolenic acid is the leading omega-3 fatty acid found in food, and it is found in canola, flaxseed, soybean, walnut, and wheat germ oils. Other good sources include ground flaxseed, walnuts, and soy products.
The body converts alpha-linolenic into DHA and EPA (also omega-3s). DHA and EPA are found in fatty fish such as salmon and mackerel.
Americans get more than enough linoleic, but not enough alpha-linolenic.

14. Essential Fatty Acids (cont’d)
Both EFAs:
Are vital to normal growth and development in infants and children,
Maintain the structural parts of cell membranes
Have a role in the proper functioning of the immune system
Are used to make eicosanoids.
Eicosanoids made from linoleic acid tend to increase blood pressure, blood clotting, and inflammation.
Eicosanoids made from alpha-linolenic acid dilate blood vessels and reduce blood clotting and inflammation.

15. Rancidity
Deterioration of fat, resulting in undesirable flavors and odors.
Saturated fats are more resistant to rancidity than unsaturated fats.
Rancidity is hastened by heat and ultraviolet light.
To prevent rancidity, store fats and oils tightly sealed in cool, dark places.

16. Cholesterol An odorless, white, waxy, powdery substance.
Cholesterol is present in every cell in your body. It is needed to make bile acids, to make cell membranes, many hormones (such as sex hormones), and vitamin D.

17. Cholesterol (cont’d)
Cholesterol is found only in foods of animal origin: egg yolks, meat, organ meats, poultry, fish, milk, and milk products. Lower-fat milk products contain less cholesterol than full-fat milk products.
We take in about 200 to 400 milligrams of cholesterol daily and the liver and body cells also make cholesterol (about 700 milligrams), therefore it is not an essential nutrient.

18. Lecithin A phospholipid.
Functions as a vital component of cell membranes.
Also acts as an emulsifier.

19. Digestion, Absorption, & Metabolism
Mouth – Lingual lipase.
Stomach – Gastric lipase.
Intestine
Bile acids
Pancreatic lipase
Intestinal lipase
Once absorbed, triglycerides are reformed.

20. Lipoproteins
Protein-coated packages that carry fat and cholesterol through the bloodstream.
Chylomicron
Very low-density lipoprotein (VLDL)
Low-density lipoprotein (LDL)
High-density lipoprotein (HDL)

21. Lipids and Health Heart disease
Too much circulating cholesterol leads to plaque and atherosclerosis
Angina
Myocardial infarction
Stroke
Main source of cholesterol buildup: LDL

22. Lipids and Health (cont’d.)
What affects cholesterol levels?
Saturated fat, trans fat, and cholesterol in diet
Mono- and polyunsaturated fat in diet
Weight
Physical activity
Age and gender
Heredity

23. Lipids and Cancer
Cancer is the second leading cause of death in the U.S.
Fat may be involved in certain cancers such as prostate cancer.

24. Dietary Recommendations for Fat
No RDA or AI for total fat (except for infants), saturated fat, cholesterol, or trans fats.
AMDR for total fat
1–3 years old % of kcal
4–18 years old % of kcal
Over 18 years old % of kcal
AI set for essential fatty acids.
DGA and AHA recommend 10% or less from sat. fat, less than 300 mg of cholesterol daily, and replace sat fats with poly and mono fats such as fish and nuts.
If fat intake is higher than 30%, use monounsaturates.

25. Percentage of Kcal From Fat & Percentage of Fat By Weight
Percentage of kcalories from fat
27 kcal from fat x 100 = 19 percent
140 kcal
Percentage of fat by weight

26. Ingredient Focus: Milk, Dairy & Eggs
Cheese
Eggs

27. Fat Substitutes Water Carbohydrate-based Protein-based – Simplesse
Cellulose gel
Carrageenan
Polydextrose
Starch
Modified food starch
Dextrins and maltodextrins
Gums
Protein-based – Simplesse
Fat-based – Olestra

28. Copyright ©2007 John Wiley & Sons, Inc.
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