Fats

Functions of Fats in the Body Protect vital organs Digestion-fat in food is digested and absorbed into adipose, or fatty, tissue Energy provider and reserve- helps the body maintain a constant temperature Production and regulation of steroid hormones Maintaining nerve impulse transmission- myelin sheath Major component of cell membranes Transport the fat-soluble vitamins A, D, E, and K

Functions of Fats in Foods Energy-9 kcal/gram Essential nutrients Flavor and satisfaction Fat substitutes are not absorbed and therefore do not provide energy or essential nutrients but may provide flavor and satisfaction Engineered fats –Simpless –Olestra –Carrageenan –Guar gum

Classes of Fats Lipids Glycerides Triglycerides Fatty acids –Saturated –Monounsaturated –Polyunsaturated Lipoproteins

Lipids Organic substance made from carbon, oxygen, and hydrogen Hydrophobic-do not dissolve in water General term for a group of compounds: -Oils, fats, waxes, and cholesterol

Triglycerides Basic unit of fat and are composed of three ("tri-") fatty acids individually bonded to three carbons of glycerol Comes from the diet (meats and plant oils) and our liver Found in the blood stream-blood fats Lipids are primarily stored as triglycerides in adipocytes Elevated levels linked to Coronary Artery Disease

Fatty Acids Saturated Fatty Acid: –Filled or “saturated” with hydrogen Unsaturated Fatty Acid: –Not completely filled with hydrogen atoms; less heavy and dense: Monounsaturated: –One unfilled spot Polyunsaturated: –Two or more unfilled spots

Saturated Fatty Acids State of being filled; fat is harder and solid. It’s structure is filled with all the hydrogen atoms it can hold.

Saturated Fats Examples of saturated fats: –Butterfat, coconut oil, palm oil, palm kernel oil, animal fat (bacon, lard, egg yolk, dairy fat, fatty meat)

Foods High in Monounsaturated Fatty Acids Olive oil Canola oil Peanut oil Sesame oil Grapeseed oil Avocados Hazelnuts Almonds Cashews Sesame seeds Pumpkin seeds Macadamia nuts

Foods High in Polyunsaturated Fatty Acids Safflower oil Sunflower oil Corn oil Soybean oil Cottonseed oil Salmon Mackerel Herring Trout Walnuts Sunflower seeds

Most foods contain a combination of saturated, monounsaturated and polyunsaturated fats: Corn Oil-59% polyunsaturated and 24% monounsaturated fatty acids Olive Oil-74% monounsaturated and 8% polyunsaturated fatty acids Peanut Oil- 46% monounsaturated and 32% polyunsaturated fatty acids Butter-62% saturated fatty acids Coconut Oil-86% saturated fatty acids

Essential Fatty Acids Polyunsaturated fatty acids –Linoleic (omega-6) –Alpha-linolenic (omega-3) These fats MUST come from the foods we eat. We cannot produce these as we can the other types of fatty acids (saturated, monounsaturated and cholesterol) 10% of a daily dietary intake needs to come from essential fatty acids

Essential Fatty Acids Functions: –Reduces inflammation –May prevent risk factors associated with chronic diseases such as heart disease, cancer, and arthritis –Aids in brain memory, performance, and behavioral function –Infants who do not get enough omega-3 fatty acids from their mothers during pregnancy are at risk for developing vision and nerve problems –Symptoms of omega-3 fatty acid deficiency may include fatigue, poor memory, dry skin, heart problems, mood swings or depression, and poor circulation

Linoleic (omega-6) Food Sources Safflower oil (richest natural source) Sunflower oil Soybean oil Cottonseed oil Evening primrose oil Borage oil Meat, poultry, and eggs

Alpha-linolenic (omega-3) Food Sources Flaxseed oil (highest linolenic content of any food), flaxseeds, and flaxseed meal Soybean oil, canola oil, and wheat germ oil Hempseed oil and hempseeds Walnuts, pumpkin seeds, brazil nuts, and sesame seeds Vegetables: grape leaves, kale, spinach, mustard greens, turnip greens, arugula, brussel sprouts, asparagus, cabbage, artichokes, broccoli, squash, sweet peppers, avocados, okra, peas Salmon, herring, mackerel, sardines, anchovies, albacore tuna, and caviar

Lipoproteins Combinations of triglycerides, cholesterol, and fat soluble vitamins, and proteins Transport lipids and cholesterol in the blood They vary in density according to the fat load they carry –Low Density Lipoproteins (LDL’s) Carry cholesterol from the liver to cells of the body –High Density Lipoproteins (HDL’s) Collect cholesterol from the body's tissues, and bring it back to the liver

Cholesterol Not a fat A fat related compound Soft waxy substance found in the bloodstream Liver makes about 2 grams per day No cholesterol in plant foods Functions: –Production of testosterone and estrogen –Synthesis of Vitamin D –Formation of Bile-aids in fat digestion Food sources: –Dairy, meat, liver, kidneys, and eggs Limit intake to less than 300 mg daily

Healthy Cooking Oils Olive oil Canola oil Flax seed oil Peanut oil Safflower oil Sunflower oil Corn oil Bad Cooking Oils Vegetable shortening Hard margarine Butter Palm oil Palm kernel oil Coconut oil

Hydrogenation Process of forcing hydrogen atoms into the holes of unsaturated fatty acids Turns liquid fat (oil) into solid fats-longer shelf life and creamier Destroys essential fatty acids This process creates a new fat called trans fatty acids- body cannot use this fat and is deposited into arterial walls Heart disease risk Trans fatty acids are found in margarine, shortening, commercial baked foods like cookies, crackers, muffins, and cereals Trans fat is similar to saturated fat because it tends to increase LDL cholesterol levels, but dissimilar because it also lowers HDL cholesterol levels as well

Digestion of Fats The primary digestion action occurring in the mouth is mechanical. Foods are broken up into smaller particles through chewing and moistened for passage into the stomach Little, if any, chemical fat digestion takes place in the stomach Small Intestine –Fat digestion occurs here –Enzymes from the pancreas –Bile from the gallbladder Fat emulsifier: breaks fat into smaller particles allowing enzymes to penetrate it –Absorption

Dietary Fat Requirements percent of your daily calories Less than 10% from saturated fat Linoleic acid (omega-6): –17 g/day for men –12 g/day for women Linolenic acid (omega-3): –1.6 g/day for men –1.1 g/day for women Dietary cholesterol be limited to 300 mg/day Trans Fat as low as possible Fat contains 9 calories per gram

Assignment Refer to page 43 Answer questions Critical Questions 1, 3, and 4