What Are Lipids? FaWy Acids Are Key Building Blocks. Lipids Include. Chapter 5 Lipids: Not Just Fat 6/17/16

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1 What Are Lipids? Chapter 5 Lipids: Not Just Fat BIOL 103 Essen@al nutrients Provide energy Help transport fat- soluble nutrients throughout the body Contribute greatly to the flavor and texture of food Lipids Include Triglycerides In body: stored in In food: fats and oils Phospholipids Plant and animal origin Body can make them Soluble in fat and water Sterols Most well known: Cholesterol FaWy Acids Are Key Building Blocks FaWy acid Determines whether a fat is solid or liquid at room temperature Basic structure: (-COOH); (-CH 3 ) 1

FaWy Acids Are Key Building Blocks Chain length FaWy acids differ in chain length Lengths vary from 4 to 24 carbons Grouped as short- chain, medium- chain, and long- chain FaWy Acids Are Key Building

2 FaWy Acids Are Key Building Blocks Chain length FaWy acids differ in chain length Lengths vary from 4 to 24 carbons Grouped as short- chain, medium- chain, and long- chain FaWy Acids Are Key Building Blocks Chain Length Shorter fawy acids remain at room temperature and even with refrigera@on Shorter fawy acids also are more water- soluble FaWy Acids Are Key Building Blocks Satura@on Saturated fa.y acids All bonds between carbons Unsaturated fa.y acids One or more carbon bonds is a bond 1. Monounsaturated fa.y acid (MUFA) 2. Polyunsaturated fa.y acid (PUFA) Fats with more double bonds are generally more 2

inflamma@on, and increase triglycerides in your blood.

3 FaWy Acids Are Key Building Blocks Cis vs. trans Unsaturated fawy acids can vary in shape Cis fa.y acids Trans fa.y acids Produced by hydrogenaaon Trans Fat In health, trans fawy acids are known to raise LDL ( bad ) cholesterol, and lower HDL ( good cholesterol ), promote systemic inflamma@on, and increase triglycerides in your blood. History and how it is made: In Europe (1910): needed a cheaper buwer subs@tute for soldiers In US (1960s): People wanted to eat a healthier and cheaper buwer à food scien@sts decided to hydrogenate vegetable oil to solidify them What are the posi@ve and nega@ve consequences of hydrogena@ng a fat? Oxida@on causes food to spoil and damage Pros Cons 3

FaWy Acids are Key Building Blocks Nonessen@al and essen@al fawy acids 1.

4 FaWy Acids are Key Building Blocks and fawy acids 1. fawy acids Can be made in the body Not to have in your diet FaWy Acids Are Key Building Blocks and FaWy Acids 2. fawy acids Must come from food Cannot be made by the body Two families: Omega- 3 (alpha- linolenic acid) Omega- 6 (linoleic acid) Pre- cursors to eicosanoids Structure Glycerol + 3 fawy acids Most fawy acids exist as part of triglyceride molecules Triglycerides 4

Triglycerides Apple vs. Pear Func@ons 1. Energy source: 9 kcal/g 2. Energy reserve: form of stored energy in adipose @ssue 3. Insula@on and protec@on: 1. Visceral fat 2.

Sensory quali@es (flavor, odor, texture) in food Triglycerides in Food Found in a variety of fats and oils Classified by their most prevalent type Saturated fawy acids: foods and

5 Triglycerides Apple vs. Pear 1. Energy source: 9 kcal/g 2. Energy reserve: form of stored energy in 3. Insula@on and protec@on: 1. Visceral fat 2. Subcutaneous fat 4. Carrier of fat- soluble nutrients 5. Sensory quali@es (flavor, odor, texture) in food Triglycerides in Food Found in a variety of fats and oils Classified by their most prevalent type Saturated fawy acids: foods and tropical oils Polyunsaturated fawy acids: plant or animal based Omega- 3: soybean, flaxseed oils; salmon, tuna Omega- 6: seeds, nuts, corn oil, meat, poultry, eggs Phospholipids Structure Glycerol + two fawy acids + phosphate group Compa@ble with both fat and water: ideal emulsifier Keep fat suspended in water Keep oil and water mixed 5

fluids Selec@vely allow both fawy and water- soluble substances into the cell Store fawy acids temporarily

Role in Fat Diges@on and Transport Mouth and Stomach Break fats into @ny par@cles for diges@on Intes@ne Con@nue

6 Phospholipids 1. Perfect structural element for cell membranes Able to communicate with watery environments of blood and cell fluids allow both fawy and water- soluble substances into the cell Store fawy acids temporarily Phospholipids 2. Role in Fat and Transport Mouth and Stomach Break fats for emulsifying fat Blood Coat the surface of the lipoproteins that carry lipid to their in the body Phospholipids Emulsifiers (lecithin) in the human body Lecithin is a phospholipid with choline Role: Forms micelles which are used to emulsify fats during diges@ons 6

7 Phospholipids Emulsifiers (lecithin) in food industry Lecithin is a blend of phospholipids with different nitrogen- containing compounds Func@on: Used as an emulsifier to combine two ingredients that don t ordinarily mix, such as oil and water Can be used in high- fat powered products helps mix fawy compounds with water Phospholipids in Food Occur naturally in plants and animals, but in much smaller amounts than triglycerides Abundant in egg yolks, liver, soybeans, peanuts Not a dietary essen@al A category of lipids that include cholesterol Structural characteris@cs: Mul@ple ring structure Contain no fawy acids Sterols Sterols Cholesterol func@ons: 1. Structural component of cell membranes 2. Precursor to other substances Examples: Cholesterol synthesis in Sterols in food Found only in foods 7

Lipid Diges@on and Absorp@on Diges@on of Triglycerides and Phospholipids Mouth Chewing and lipase Stomach Breaks triglycerides via lipase down

and short- chain fawy acids into the bloodstream Lipid Diges@on and Absorp@on Small Intes@ne (cont.

8 Lipid and of Triglycerides and Phospholipids Mouth Chewing and lipase Stomach Breaks triglycerides via lipase down to diglycerides and free fawy acids Small and lipase emulsify and break down the fats for cells absorb glycerol and short- chain fawy acids into the bloodstream Lipid and Small (cont.) Bile salts form micelles (water- soluble globules with a fawy core) to carry long chain fawy acids to the microvilli Bile salts return to the liver to be used again Enterohepa1c Circula1on 8

Lipid Diges@on Lipid Absorp@on To travel in

lipids from intes@nes to cells and liver

9 Lipid Lipid To travel in the bloodstream, lipids are packaged into lipoprotein carriers Lipoprotein leave the cell as Chylomicron Deliver dietary lipids from to cells and liver Chylomicron goes to lymph system (lacteals) à bloodstream 9

Transporta@on of Lipids in the Body Lipids packaged into

Lipoproteins differ by size, density, and the composi@on of their

Very- Low- Density Lipoproteins (VLDLs) Deliver triglycerides to

Lipoproteins (IDLs) Converted to low- density lipoproteins

10 of Lipids in the Body Lipids packaged into lipoprotein carriers in order to travel in the bloodstream Lipoproteins differ by size, density, and the of their lipid cores: VLDL IDL LDL HDL of Lipids in the Body Very- Low- Density Lipoproteins (VLDLs) Deliver triglycerides to cells of Lipids in the Body Intermediate- Density Lipoproteins (IDLs) Converted to low- density lipoproteins of Lipids in the Body Low- Density Lipoproteins (LDLs) Deliver cholesterol to cells 10

Transporta@on of Lipids in the Body High- Density Lipoproteins (HDL) Pick up cholesterol for removal or recycling Lipids in the Body 1.

11 of Lipids in the Body High- Density Lipoproteins (HDL) Pick up cholesterol for removal or recycling Lipids in the Body 1. Very- low- density lipoproteins (VLDL): Deliver triglycerides to cells 2. Intermediate- density lipoproteins (IDL) Returns to liver and is converted to LDL 3. Low- density lipoproteins (LDL) Deliver cholesterol to cells, which body uses to synthesize membranes, hormones, etc. Returns to liver aoerwards 4. High- density lipoproteins (HDL) Pick up cholesterol for removal or recycling Lipoprotein Pathway Summary for Fat Intake Recommended intake Reduce saturated fat, trans fat, and cholesterol Total fat: 20 35% of calories Less than 10% of calories from saturated fat 2010 Guidelines: Less than 300 mg per day of cholesterol 11

12 for Fat Intake fawy acid requirements Linoleic acid/omega- 6 fawy acids should provide about 2% of calories Requirements for omega 3 fawy acid is less well known Omega- 6 and omega- 3 balance Ra@o of omega- 6 to omega- 3 fawy acids Why would it be bad to consume too much omega 3 fawy acids? Recommenda@ons for Fat Intake Role of fat replacers Different types of composi@on Olestra: Sucrose + fawy acids Indiges@ble provides no calories Reduces absorp@on of fat- soluble vitamins 1. Heart disease/cardiovascular Diseae Leading cause of death in US (1 death/ minute) Major risk factors: High blood cholesterol (High LDL, low HDL) Smoking High blood pressure 12

13 2. Obesity Determined by excessive of body fat leading to a body weight in rela@on to height that is significantly greater than some accepted standard. High- fat diets promote weight gain Significant within the U.S. popula@on 34.9% of American adults 17% of American children and adolescents 3. Metabolic syndrome Affects ¼ of American adults Cluster of at least three symptoms: Excess abdominal fat High blood glucose High serum triglycerides Low HDL cholesterol High blood pressure 4. Cancer Results from complex mix of lifestyle, hereditary, and environmental factors Role of nutri@on and diet complex Evidence suggests 30-40% are due to poor food choices and physical inac@vity Some dietary factors act as promoters, while others serve a protec@ve role Cancer Dietary and lifestyle factors for reducing cancer risk Maintain a healthful weight Adopt a physically ac@ve lifestyle Consume a healthy diet Limit alcohol consump@on 13

14 Reducing heart disease risk AHA diet and lifestyle Consume an overall healthy diet Aim for a healthy body weight Aim for a desirable lipid profile Aim for normal blood pressure Aim for normal blood glucose levels Be physically ac@ve Avoid use of and exposure to tobacco products Reducing heart disease risk AHA recommenda@ons Balance calorie intake and physical ac@vity to achieve or maintain a healthy body weight Consume a diet rich in fruits and vegetables Choose whole- grain, high- fiber foods Consume fish, especially oily fish, at least twice a week Limit your intake of saturated and trans fat and cholesterol Reducing heart disease risk AHA recommenda@ons (cont.) Minimize your intake of beverages and foods with added sugars Choose and prepare foods with liwle of no salt If you consume alcohol, do so in modera@on Follow the AHA recommenda@ons when ea@ng outside of the home Puung It All Together Healthy People 2020 objec@ves target reducing deaths from heart disease and stroke and reducing the number of adults with high blood cholesterol levels 14

What Are Lipids? Fa\y Acids Are Key Building Blocks. Lipids Include. Chapter 5 Lipids: Not Just Fat 2/21/17

$What Are Lipids? Fa\y Acids Are Key Building Blocks. Lipids Include. Chapter 5 Lipids: Not Just Fat 2/21/17$ What Are Lipids? Chapter 5 Lipids: Not Just Fat BIOL 103 SP2017 EssenBal nutrients Provide energy Help transport fat- soluble nutrients throughout the body Contribute greatly to the flavor and texture