Lipids Triglycerides –Fats and oils Phospholipids –Lecithin Sterols –Cholesterol

Objectives After reading Chapter 4, class discussion and learning activities, you will be able to –Identify types (classification) of lipids –Describe the role of lipids in the body –Discuss lipid digestion, absorption and transport –Calculate calories from fat

Objectives Identify food sources of different types of fats Discuss the health related effects of lipids Provide recommended intakes of different types of fats Identify ways to improve the type of fat consumed Identify ways to reduce saturated and trans fat intake

4 Triglycerides p. 128 Fig 4-1 glycerol

Triglycerides glycerol + 3 fatty acids  triglyceride

Fatty Acids Length of fatty acid –18-24 carbons in length Degree of “Hydrogen” Saturation p. 129

Omega # Point - Location of unsaturation –Omega-3 fatty acid –Omega-6 fatty acid

Fats-Oils Vary % weight of different chain combinations Canola Oil –62% monounsaturated, 32% polyunsaturated, 6% saturated Butter Fat (cow) –56% saturated, 29% monounsaturated, 2% polyunsaturated

Unsaturated Fats Plant; soft or liquid Monounsaturated Fats –(Up to 15% of total calories) –Canola –Olive –Peanut oil, peanuts and peanut butter –Avocado –Almonds, cashews, hazelnuts, pecans, pistachios

Unsaturated Fats Polyunsaturated Fats (Up to 10% of total calories) –Safflower –Soy –Corn –Sesame –Sunflower –Walnuts –Seeds –Whole grains –Fish oils –Flax

Hydrogenated-Trans Fats Plant oils Processed to alter hydrogen bonds, add hydrogen Creamy, solid fat –Taste, mouth feel –Extend shelf-life ? how body uses…. –Lipase does not digest, transport, process

Trans Fat Food Sources Shortening Stick margarine Processed foods –Crackers, cookies, frosting, breading, creamers Restaurants, fast food, movie theater popcorn, frozen custards Vegan religious foods – Kosher, Islamic, Seventh Day Adventist “hydrogenated” or “partially hydrogenated” on ingredient list “0 Trans Fat” – can still contain up to 0.5 grams

Essential Fats Body can not produce Omega-3 and omega-6 fats Functions: –Decrease inflammation responses –Decrease blood clots –Reduces blood triglycerides –Regulate blood pressure –Boost immune system Prostaglandins, leukotrienes –Protect cell membranes –Regulate hormones –Skin health –Brain, eye, lung development in babies –On and on and on……

Omega 3 Fatty Acids Average intake low Types –EPA (eicosapentanoic acid) Fish, fish oil supplements –DHA (docosahexanoic acid) Fish, eggs, breastmilk –Alpha-Linolenic acid Flaxseed, canola oils Walnuts, wheat germ, soybeans

Flaxseed Up to1 tablespoon oil a day Ground flaxseed Fortified foods Flaxseeds- fiber

Omega-6 Fatty Acids Linoleic Plant oils, olive oil, whole grains, beef/poultry, nuts, seeds Average intake adequate

Saturated Solid Animal or tropical oils (< 10% of total calories) Food Sources –Beef –Pork, bacon –Poultry (skin) –Butter, lard –Cheese, whole milk, cream, half-n-half –Coconut and palm oils

Degree of Saturation Determines: –Firmness –Stability Oxidation

Rancidity Deterioration of fat; resulting in undesirable flavor/odor –Hydrolytic: Separation of glycerol from fatty acids Butter –Oxidative: Loss of hydrogen in presence of air/heat Polyunsaturated fatty acids

Fat Digestion Triglycerides  monoglycerides, fatty acids, glycerol Mouth –Melting –Lingual Lipase Stomach –Churning and mixing –Gastric Lipase

Fat Digestion Small intestine –Gallbladder releases bile –Bile emulsifies fat so it can be more fully digested Pancreatic lipase Intestinal lipase

Fat Digestion

p.142

Protein carrier of fats/oils, cholesterol EFA, unsaturated, sat fats to cells; unused trans & saturated to liver Unused & trans to VLDL To fat stores LDL taken up by cells LDL taken up by blood vessel HDL picks up plaque, To liver for disposal.

Lipid Transport Lipoproteins –Chylomicrons –VLDL = very-low-density lipoproteins –LDL = low-density lipoproteins –HDL = high-density lipoproteins

Lipid Transport Lipoproteins and health –LDL: carries cholesterol from liver to the cells of the body High=Less healthy –HDL: carries cholesterol from the cells back to the liver High=More healthy

Lipid Transport

Sterols Found in plants and animals Cholesterol is most abundant Found in animals only Found in every cell in man’s body Body makes ~700mg/day Dietary intake 300 mg/day

Dietary Cholesterol

Sterols Roles of sterols –Manufacture bile acids –Make hormones Estrogen and testosterone –Make Vitamin D –Maintain cell membranes

Phospholipids Emulisifiers Lethicin

Functions of Triglycerides Fat stores –Energy- 9 calories/gram –Protection –Insulation Provide essential fatty acids Insure efficient use of protein and carbohydrate Flavor, satiety

Health Effects of Lipids Risks from trans fats –Alter blood cholesterol like saturated fats –Raise LDL cholesterol –Lower HDL cholesterol at high intakes –Increase inflammation & insulin resistance –AI = 5 gm/day Risks from cholesterol –Beware cholesterol sensitivity Limit intake <300 mg/day

Health Effects of Lipids Benefits from monounsaturated fats –Lowers LDL and total cholesterol –Lowers blood clotting factors –Lowers blood pressure –Provides phytochemicals which act as antioxidants

Health Effects of Lipids Benefits from omega-3 fats –Prevent arrhythmias –Lower blood pressure –Improve blood vessel function –May ease inflammation –Prevent repeat heart attack 1 gm supplement daily for 3 years Balance omega-6 and omega-3 intakes

DRI Recommended Intakes 20-35% of total calories from total fat About grams (2000 calories) Up to 15% of total calories from monounsaturated 33 grams or less (2000 calories) Up to 10% of total calories from polyunsaturated 10% or less of total calories from saturated fat 22 grams or less each (2000 calories)

Recommended Intakes of Fat 1-2% of calories or less from trans fats 2-4 grams or less Cholesterol: mg/day Linoleic acid AI –12-17 grams Linolenic acid AI – grams

Calculating % Calories From Fat 85 grams total fat, 1860 calories 85 x 9 calories/gram = 765 calories  1860 = 41% of total calories from fat 36 grams saturated fat, 1860 calories 36 x 9 calories/gram = 324 calories  1860 = 17% of total calories from saturated fat

Calculating Fat Grams Calorie goal, % fat goal –1600 calories, 25% of calories from fat 1600 x.25 =400 calories  9 calories/gram = 44 grams a day

Fat Distribution in Diet

Generally…What To Do…… Variety of oils –Increase monounsaturated –Moderate poly –Lower saturated –Trans fat as low as possible Increase omega 3 when you can Type Amount

Choose The Most Unsaturated Possible

Oil Blends

Ingredient Guidelines Limit added fats Use reduced/low fat –Butter/margarine –Sour cream –Cheese sauces –Cream sauces

Ingredient Guidelines Use fat free milk and milk products Limit cheese Part skim milk cheese

Ingredient Guidelines Use meat sparingly Use lean meats Use meat alternatives

Changing Guidelines for Fat Intake

Changing Guidelines Cook with olive oil or canola oil Monounsaturated fatty acids Nibble on nuts Omega-3 polyunsaturated fatty acids Feast on fish Marine omega-3 PUFA But beware of mercury