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

• Avocados

• Canola oil

• Hazelnuts

• Peanut oil

• Almonds • Cashews

• Sesame oil

• Sesame seeds

• Grapeseed oil

• 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 • 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