Chapter 5: Lipids: Fats, Phospholipids, and oils, nuts, avocados ... fats Saturated fats Monounsaturated fats Omega-3 Omega-6 Industrialized = trans Animal fats Tropical fats Cold-water,

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Text of Chapter 5: Lipids: Fats, Phospholipids, and oils, nuts, avocados ... fats Saturated fats...

  • Chapter 5: Lipids: Fats, Phospholipids, and Sterols

    Copyright 2012 John Wiley & Sons, Inc. All rights reserved.

  • 2012 John Wiley & Sons, Inc. All rights reserved.

    Student learning outcomes: At the end of this chapter, you should be able to:

    Discuss benefits and risks of dietary fats

    Compare and contrast types of fats

    Select foods containing healthy fats and limit unhealthy fats

  • 2012 John Wiley & Sons, Inc. All rights reserved.

    THINK about this then share within a PAIR then SHARE with the class

    Which foods in your diet provide fat?

    Why do you need fat in your diet?

    What are the benefits and consequences of a low-fat diet?

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    Sources of dietary fatsAnimal sources:

    meat, cheese, dairy

    Plant sources:

    vegetable oils, nuts, avocados

    Hidden dietary fat:

    French fries, pizza, pasta dishes, baked goods, salad dressings

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    Benefits of dietary fats

    Provide texture, flavor, aroma to foods

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    Low-fat diets

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    Lipids: a class of large biological molecules

    Lipids

    Triglycerides Phospholipids Sterols

    Unsaturated fats Cholesterol

    Saturated fats

    3 fatty acids + 1 glycerol

    In cell membranes

    In cell membranes

    Starting material

    Called fatsin the diet

    Starting material

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    Glycerol, fatty acids: chains of carbon atoms, acid at end

    Lipid types / Triglyceride

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    Lipid types / Phospholipid

    Phosphate, chains of carbon atoms

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    Lipid types / Sterols

    Multiple chemical rings

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    Carbon bonding

    Carbon can form four bonds

    Carbon

    Carbon Carbon

    Double bondSingle bond

    1

    2 3

    4

    1

    42,3

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    Saturated vs. unsaturated fatty acids

    Saturated fats: carbons are saturated by hydrogens

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    Unsaturated fats: carbons not saturated

  • 2012 John Wiley & Sons, Inc. All rights reserved.

    Saturated vs. unsaturated fats in foods

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    Monounsaturated vs. polyunsaturated fats

    Monounsaturated fats: one double bond

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    Polyunsaturated fats: more than one double bond

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    Types of fatty acids

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    Types of fatty acids

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    Types of Fatty Acids

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    Omega-3 vs. Omega-6 polyunsaturated fats

    Omega-3: first double bond at 3rd bond from omega end

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    Omega-6: first double bond at 6th bond from omega end

    Omegacarbon

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    3rd bond

    6th bond

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    Essential vs. non-essential fatty acidsEssential fatty acids cannot be made in the body, so they are essential in the diet /// Example: omega-3 fatty acids (e.g. alpha-omega-6-fatty acids) and omega-6 (e.g. linoleic acid)

    Sources:

    omega-3 = flaxseed, walnuts, soy (decreases inflammation-blood clotting-blood pressure)

    omega-6 = vegetable oils and meats (increases inflammation-blood clotting-blood pressure)

    Non-essential fatty acids can be made by the body, so they are not essential in the diet

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    Cis vs. trans-fats

    Cis fat: hydrogens on same side (like sisters)

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    Trans fat: hydrogens are across (like a transcontinental flight goes across the US)

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    Cis vs. trans-fats

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    Types of fatty acids

    Fatty acids

    Unsaturated fats

    Polyunsaturated fats

    Saturated fats

    Monounsaturated fats

    Omega-3 Omega-6

    Naturally = cisIndustrialized = trans

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    Trans-fat (trans-fatty acids)Found naturally in small amounts (e.g. dairy products)

    Large amounts created when unsaturated fatty acids are partially converted to saturated fatty acids by the industrialized process of hydrogenation

    Decreases the reactivity of lipids / used to decrease rancidity and increase shelf life

    Most dangerous dietary fat

    Look for hydrogenated oils in ingredients list // avoid this type of fat!!!

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    Trans-fat vs. palm oil

    Trans-fat food labeling led food producers to replace hydrogenated oil with palm oil

    Palm oil is a tropical oil high in saturated fat

    Increased palm oil production led to rainforest destruction

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    Trans-fat (trans-fatty acids)

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    Calculate the trans-fatFood industry able to mislead the consumer // in trans-fat labeling zero actually means 0.4 grams

    A bag of chips has 8 servings and has a trans-fat free label

    Each serving actually has 0.4 g of trans fat (label lists as 0 g of fat)

    If you eat of the bag of chips, how many grams of trans-fat have you consumed?

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    Types of fatty acids

    Fatty acids

    Unsaturated fats

    Polyunsaturated fats

    Saturated fats

    Monounsaturated fats

    Omega-3 Omega-6

    Industrialized = trans

    Animal fats

    Tropical fats

    Cold-water, fatty fish

    Flax seed

    Walnuts

    Vegetable oils

    Nuts

    Baked goods

    Processed foods

    Olive oil

    Canola oil

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    Less healthy to healthier dietary fats

    Polyunsaturated omega-6 fats

    Saturated fats

    Monounsaturated fats

    Industrialized = trans fat

    Polyunsaturated omega-3 fats

    Healthiest

    Least healthy

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    Phospholipids

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