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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 transmissionmyelin 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 • Salmon • Mackerel • Sunflower oil • Herring • Corn oil • Trout • Soybean oil • Walnuts • Cottonseed oil • 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 acidsbody 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 • 20-35 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