Unit 18 Fats and Cholesterol in Health

Facts about fats Lipids can dissolve in fat, not water Fats- solid at room temperature Oils- liquid at room temperature

Contributions of dietary fats Supply energy We need essential fatty acids (about 1 teaspoon per day) Deliver fat-soluble vitamins to the body Increase flavor and palatability of foods Contribute to the feeling of being full A component of cell membranes

Excess calories are stored as fat Regardless of their source, all extra calories (carbs, protein, fat) are stored as fat. Layer of fat under skin- subcutaneous fat- insulation Fats surround the organs- visceral fat- cushion them Excess fat- visceral fat contributes the most to heart disease (apple vs pear)

Different types of fat Triglycerides Diglycerides Monoglycerides Saturated Monounsaturated Polyunsaturated Cholesterol glycerol

Triglycerides Glycerol + 3- fatty acids = triglyceride fatty acid Glycerol +fatty acid fatty acid

Diglycerides Glycerol + 2 fatty acids = diglyceride fatty acid Glycerol +fatty acid

monoglycerides Glycerol + 1 fatty acid = monoglyceride Glycerol fatty acid

Digestion of Triglycerides Glycerol + 3- fatty acids = triglyceride fatty acid Glycerol +fatty acid = monoglyceride fatty acid

Saturated vs unsaturated fats Saturated- solid at room temperature Unsaturated- liquid at room temperature Unsaturated fat + hydrogenation = saturated fat –Saturated fat has a longer shelf life because it is less likely to oxidize

Cholesterol A fat-soluble, colorless liquid found in animals but not plants Hormones- testosterone and estrogen Component of cell membranes in animals “turns sunlight into Vitamin D” Cannot be used for energy- no calories Major component of nerves and brain

Omega-3 fatty acids Found in fish oils, flax seed, some other foods Lower risk of heart disease

hydrogenation Saturate fats by pumping hydrogen thru them

Trans fatty acids Mirror images of fatty acids found in nature Created during hydrogenation process Associated with an increased risk of heart disease

Which is better for you? Butter- saturated fat, contains cholesterol Stick Margarine- hydrogenated- contains trans fatty acids but no cholesterol Tub margarine- partially hydrogenated- contains some trans fatty acids but no cholesterol

Taking the fat out of foods Adding less fat to foods to processed foods Trimming fat from meats Removing skin from chicken Adding less fat to ground beef Adding water to ham and other meats (cheating)

Fat substitutes Are they safe? Do they replace saturated fats in the diet? What are they made from? –Carbohydrate-based –Protein-based –Fat-based –combinations

Other ways to replace fat in the diet Smaller serving size –Hamburger instead of a Big Mac –Small fries instead of large fries Use different ingredients –Veggie pizza instead of pepperoni Use a low-fat or non-fat version –1% or skim milk instead of whole or 2% Have something else instead –Fruit instead of ice cream

How much fat is in the foods you eat? Read the label Look for key words in the name –With gravy –Cream sauce –Au gratin –With cheese –Fried –Alfredo