1. The Lipids: Fats & Oils NUT SCI 242 Food & Nutritional Health
© Karen Lacey, MS ,RD, CD

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3. What are Lipids?
Lipids is the name given to a large and diverse group of substances that are not soluble in water.
The family of compounds that includes
Triglycerides (fats & oils)
Fats: lipids that are solid at room temperature
Oils: lipids that are liquid at room temperature
Phospholipids
Sterols (cholesterol).

5. I. A Primer on Fats The Functions of Fat in the Body
Energy source especially for muscles
Serves as an energy reserve
1# body fat contains 3500 kcal
30-50# of stored fat

6. Cont’d Major component of cell membranes Nourishes skin & hair
Insulates the body from temperature extremes
Cushion the vital organs to protect them from shock

9. B. The Functions of Fat in Food
Provide calories (9 per gram)
Provide satiety
Carry fat-soluble vitamins & essential fatty acids
Contribute aroma & flavor

11. Lipid Terminology
Triglycerides: the major class of dietary lipids, including fats & oils
Made up of 3 units known as fatty acids and 1 unit called glycerol (backbone)
Comprise about 95% of lipids in food and the human body

14. Cont’d Phospholipids: Sterols 2nd of three main classes of lipids
similar to a triglyceride, but contains phosphorous
Sterols
3rd of three main classes of lipids;
Cholesterol
one of the sterols
manufactured in the body for a variety of purposes

15. Cont’d
Fatty acids:
basic units of fat composed of chains of carbon atoms
an acid group at one end and hydrogen atoms attached all along their length

17. B. Essential Fatty Acids
Essential fatty acids are those that must be consumed in foods because our bodies cannot make them.
Two fatty acids, linoleic acid (omega 6) and linolenic (omega 3)acid are considered essential

19. Omega - 6 versus Omega - 3
Most Americans get adequate amounts omega-6-fatty acid because we get plenty of vegetable and nut oils such as, soy, peanut, sunflower and safflower oils or use vegetable oil margarines.
Their functions include regulation of gastrointestinal motility, secretory activity, blood clotting, regulate blood pressure, and inflammation.

21. Omega - 6 versus Omega - 3
Omega-3-fatty acid is found in dark, green leafy vegetables, flaxseeds and flaxseed oil, walnuts and walnut oil, canola oil, and soybeans and soybean oil.
Fish, shellfish, and fish oils contain two omega-3 fatty acids, eicosapentanoic acid (EPA) and docohexanoic acid (DHA).
The functions are promoting heart health, the creation of new brain cells and preventing blood clotting

23. II. Characteristics of Fats in Foods
Liquid vs Solid
More saturated a fat is, the more solid it is at room temperature
More unsaturated a fat is, the more liquid it is at room temperature

24. III. A Closer View of Fats
Chain Length (number of carbons linked together)
Shorter = more soluble in water
Saturated vs. Unsaturated (number of hydrogens the chain is holding)
Maximum = saturated
Unsaturated = one or more is missing
Point of unsaturation = site where hydrogen is missing

26. Cont’d
Saturated fatty acid: a fatty acid carrying the maximum possible number of hydrogen atoms
Animal foods such as meat, poultry and full-fat dairy products
Tropical oils such as palm and coconut

28. Cont’d
Unsaturated fatty acid: a fatty acid with one or more points of unsaturation.
Found in foods from both plants & animal sources
Monounsaturated fatty acids (one double bond)
Polyunsaturated fatty acids (two or more)

30. Cont’d
Monounsaturated fatty acid: also called a MUFA; a fatty acid containing one point of unsaturation
Found mostly in vegetable oils such as olive, canola & peanut

31. Cont’d
Polyunsaturated fatty acids: also called a PUFA; a fatty acid in which two or more point of unsaturation occur
Found in nuts, vegetable oils such as safflower, sunflower and soybean, and in fatty fish

33. III. Characteristics of Fats in Foods
Hydrogenation
The process of adding hydrogen to unsaturated fat to make it more solid and more resistant to chemical changes such as spoiling
Increasing a fat’s saturation can cause a fat to lose its unsaturated health benefits

35. C. Trans-Fatty Acids Formed when margarine is processed
Hydrogen molecules are on opposite sides of point of unsaturation
“Partially hydrogenated vegetable oil”
Link between trans fatty acids and heart disease
Table 4-3, page 107
Keep to minimum

38. V. Phospholipids
A lipid consisting of a water-soluble head and a fat-soluble tail
Contain phosphorous
Component of cell membranes
Serve as emulsifiers (allow fats and water to mix and travel in and out of cells into watery fluid on both sides)

40. Cont’d Lecithin is a common phospholipid
Often used as an emulsifier in foods such as margarine, chocolate & salad dressings

41. V. Cholesterol – a Sterol
Found only in animal products
Also made & used in the body:
Structure of cell membranes
Used to make bile for digestion
Bile: a mixture of compounds, made by the liver, stored in the gallbladder, & secreted into the small intestine
Emulsifies lipids to prepare them for enzymatic digestion & helps transport them into the intestinal wall cells

42. Cont’d Used to make the sex hormones estrogen & testosterone
Made into vitamin D with the help of sunlight
Deposited in the artery walls leading to plaque buildup & heart disease

45. VI. How the Body Handles Fat
Digestion
Emulsification
Absorption

54. VII. Lipids & Health Good vs. Bad Cholesterol

57. B. Lowering Blood Cholesterol Levels
Eat no more than 30% of calories from fat
Eat no more than 8-10% of calories from saturated fat
Eat no more than 10% of calories from PUFAs
MUFAs should make up 10-15% of total calories
Limit daily cholesterol intake to no more than 300 milligrams

58. VIII. Diet & Heart Disease
Risk Factors
High cholesterol
High blood pressure
Smoking
Diabetes
Lack of exercise
Stress
Obesity
Unhealthy diet
Age
Gender
Genetics

59. Cont’d Ways to Reduce Risk:
Limit intake of cholesterol & saturated fat
Quit smoking
Maintain a healthy weight
Eat high fiber foods
Increase physical activity
Increase fruit & vegetable consumption
Limit alcohol consumption

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61. IX. Fat in the Diet Food Guide Pyramid
3 groups traditionally account for nine-tenths of the fat in the U.S. diet
Fats, oils & sweets group
Meat, poultry, fish, dry beans, eggs & nut group
Milk, yogurt & cheese group
Most of the fat in our diets comes from animal products

63. B. Fat Substitutes Carbohydrate-based Protein-based
Help retain moisture to maintain the juiciness or creaminess that is lost with fat reduction
Carrageenan, fruit purees, gelatin, gums, starches & products made from fiber
Protein-based
Proteins are cooked & blended to form tiny round particles that trap water to maintain the mouth feel of fat
Whey protein concentrate (Dairy-Lo), or milk & egg white protein (Simplesse)

64. Cont’d
Fat-based
Are either only partially digestible or completely undigestible to prevent absorption of fat
Caprenin (substitute for cocoa butter in candy), Salatrim (found in low fat baking chips), and olestra (often found in fat free potato chips)

65. C. At the Grocery Store
Read labels to determine both the amounts & types of fat contained in foods

67. D. In the Kitchen Use canola & olive oil for baking & cooking
Prepare lean cuts of meat
Bake, broil & steam instead of frying
Use low-fat or fat-free dairy products & dressings
Season with herbs & spices rather than with fats
Incorporate plant-based protein sources such as soy & legumes

68. E. At the Table Eat more fresh fruits & vegetables
Use jam instead of butter
Limit use of high-fat condiments including mayo, butter & sour cream or use low-fat varieties
Use mostly monounsaturated vegetable oils such as olive or canola
Eat fewer high-fat desserts

69. F. Recipe Modification Egg whites Fat-free evaporated milk
Fat-free sour cream
Fruit purees
Fat-free cream cheese
Oils

70. Class Presentation Assignment
What is a heart attack? What causes a heart attack? What are the signs of a heart attack? Steps to take for avoiding a heart attack.
What is normal blood pressure? What is high blood pressure? Who is at risk of having high blood pressure? How do you know if you have it? What is the danger if high blood pressure? How can it be prevented?
What is Cholesterol? What are the dangers of having high Cholesterol? Describe how to lower high cholesterol.
What is a stroke? What are the causes of strokes? What are the signs of a stroke? Steps to take to avoid a heart attack.
What is Transient Ischemic Attack (TIA)? What are the causes and signs of TIA? Steps to take for avoiding TIA.
What is cardiovascular disease? What are the types of cardiovascular diseases? What are the causes? What are the possible treatments? How can it be prevented?
Describe the steps for Basic CPR. Include as much information as possible.