chapter 5 the lipids: fats, oils, phospholipids, and sterols

Chapter 5Chapter 5

The Lipids: Fats, Oils, The Lipids: Fats, Oils, Phospholipids, and SterolsPhospholipids, and Sterols

Nutrition: Concepts & Controversies, 12e Nutrition: Concepts & Controversies, 12e Sizer/WhitneySizer/Whitney

Learning ObjectivesLearning Objectives

Describe how and where dietary lipids are broken down and absorbed during digestion and how they are transported throughout the body.

Describe the significance of the blood tests for HDL and LDL cholesterol.

Describe the roles of omega-3 and omega-6 fatty acids in the body, and discuss which may be too low in some people’s diets and how they can increase their intakes.

Learning ObjectivesLearning Objectives

Develop a diet plan that provides enough of the right kinds of fats within calorie limits.

Discuss evidence for the benefits and drawbacks of specific dietary fats in terms of their potential effects on human health.

Introduction Introduction

Diet moderate in fats Lipids are necessary and valuable Lipids can harm health

Three classes of lipids Triglycerides Phospholipids Sterols

Usefulness of Fats in the BodyUsefulness of Fats in the Body

Chief storage form of energy Provides most energy for body’s work

Adipose tissue Secretes hormones

Purposes of fat Shock absorbers, insulation, cell

membranes Fat-soluble substances

A Fat CellA Fat Cell

Triglycerides: Fatty Acids and Triglycerides: Fatty Acids and GlycerolGlycerol

Triglycerides Glycerol backbone Three fatty acids

Fatty acid differences Chain length Saturation

Animal species make triglycerides

Saturated Versus Unsaturated Saturated Versus Unsaturated Fatty AcidsFatty Acids

Saturation Hydrogen atoms

Levels of saturation Saturated Unsaturated

PolyunsaturatedMonounsaturated

Three Types of Fatty AcidsThree Types of Fatty Acids

Phospholipids and SterolsPhospholipids and Sterols

Phospholipids Glycerol, two fatty acids, and a phosphorus

moleculeSoluble in water and fat

Emulsifier Sterols

Roles in the body Plant sterols

Digestion and Absorption of FatsDigestion and Absorption of Fats

Digestion Stomach Small intestine

Bile Pancreas

The Process of Lipid Digestion The Process of Lipid Digestion and Absorptionand Absorption

Storing and Using the Body’s FatStoring and Using the Body’s Fat

Body conserves fat molecules Fat depots Excess carbohydrate

Call for energy Dismantle stored triglycerides

Release fatty acids into blood Carbohydrate’s role

How to use more fat for energy…

Dietary Fat, Cholesterol, and Dietary Fat, Cholesterol, and HealthHealth

Heart and artery disease Saturated and trans fats Beneficial fats

Cancer Diet high in saturated fats

Obesity Overconsumption of calories

Lipoproteins and Heart Disease Lipoproteins and Heart Disease RiskRisk

Lipoprotein movement in the body Liver

Types of lipoproteins Chylomicrons Very-low-density lipoproteins (VLDL) Low-density lipoproteins (LDL) High-density lipoproteins (HDL)

LipoproteinsLipoproteins

Lipoproteins and Heart Disease Lipoproteins and Heart Disease RiskRisk

LDL and HDL difference Size and density Delivery and

scavenging Inflammation Heart attack risk

Oxidation of LDL Phytochemicals

Food Fat, Saturated Fat, and Food Fat, Saturated Fat, and CaloriesCalories

Top Contributors of Saturated Top Contributors of Saturated Fats to the U.S. DietFats to the U.S. Diet

The Need for Essential Fatty The Need for Essential Fatty AcidsAcids

Essential fatty acids Linoleic acid and

linolenic acid Functions

Eicosanoids

DRI recommendations Deficiencies

Omega-6 and Omega-3 Fatty Omega-6 and Omega-3 Fatty Acid FamiliesAcid Families

Linoleic Omega-6 fatty acid Arachidonic acid

Linolenic acid Omega-3 fatty acid DHA and EPA

Heart diseaseBrain function and vision Inflammation

Fish Oil Intakes and Fish Oil Intakes and Cardiovascular Death Rates Cardiovascular Death Rates

Recommendations for Omega-3 Recommendations for Omega-3 Fatty Acid IntakeFatty Acid Intake

Competition for metabolic enzymes Consumption levels

Lacking omega-3 fatty acids Fish oil supplements

Health concerns with fish oil supplements Omega-3 enriched foods Flaxseed

Mercury in Fish SpeciesMercury in Fish Species

Effects of Processing on Effects of Processing on Unsaturated FatsUnsaturated Fats

Hydrogenation Effects on fats

Oxidation of unsaturated oils Hydrogenation of oils

Benefits of hydrogenation Nutrient losses Alternatives to hydrogenation

Hydrogenation Yields Both Hydrogenation Yields Both Saturated and Trans-Fatty AcidsSaturated and Trans-Fatty Acids

Effects of Processing on Effects of Processing on Unsaturated FatsUnsaturated Fats

Trans-fatty acids Polyunsaturated fats

Change in chemical structure

Health effects LDL and HDL cholesterol Similarities with saturated fat

Trans fat in foods

Fat in the DietFat in the Diet

Meat, poultry, fish, dried peas & beans, eggs, & nuts Four categories for meat Limit intake to 5 to 7 ounces per day Choosing low-fat meats

Ground turkey or chicken vs. beef

Milk, yogurt, and cheese Foods not included in this category

Grains

Calories, Fat, and Saturated Fat Calories, Fat, and Saturated Fat in Cooked Ground Meat Pattiesin Cooked Ground Meat Patties

Lipids in Milk, Yogurt, and CheeseLipids in Milk, Yogurt, and Cheese

Lipids in Bread, Cereal, Rice, and Lipids in Bread, Cereal, Rice, and PastaPasta