Chapter 3


Learning Objectives:

  • Identify how fats are classified

  • List the major functions of fats both in the diet and in the body

  • Discuss the relationships to health of cholesterol, saturated fat, polyunsaturated fat, trans-fatty acids, and monounsaturated fat.

  • List three current recommendations of the Food and Nutrition Board of the National Research Council that pertain to fat.

Fats:

  • Lipids: Include true fats and oils, and fat like sompounds like lipoids and sterols.

  • Fats are a major source of fuel for the body

  • Dietary fat: Is found in both animal and plant products.

  • Animal fats: which consist of a larger content of saturated fats. And have a higher melting point.

  • Plant derived fats: Are normally in the form of oils, lave a lower melting point and comprising more unsaturated fats than animal products

  • Lipids are insoluble in water and greasy to the tough.

Terms:

  • Lipids are composed of carbon, hydrogen, oxygen.

  • True Fats: Is one molecule of glycerol joined to one, two, or three fatty acids molecules.

  • Glycerol is the backbone of a fat molecule

  • A Fatty Acid is composed of a chain of carbon atoms with hydrogen and few oxygen atoms attached

  • The chain joined to the glycerol molecule vary in length and composition

Monoglyceride: When a single fatty acid is joined to a glycerol molecule, the resulting fat is called a monoglyceride.

Diglyceride: When two fatty acids are joined to a glycerol molecule.

Triglycerides: When three fatty acids are joined to a glycerol molecule.

  • Most the fat in our diets and body is in the form of triglycerides.

  • Excess is stored in the Adipose Cells

  • The body has virtually unlimited capacity to store fat.

Length of Fatty Acid Chain:

  • Vary in length of chains

  • Carbon atoms present range from 2-24

Degree of Saturation:

  • Degree of saturation depends on the extent to which hydrogen is joined to the carbon atoms

  • Saturated fatty acid is filled with as many hydrogen atoms as the carbon atoms can bond with and has no double bounds

  • Double bond describes the type of chemical connection between two neighboring carbon atoms

  • Unsaturated Fatty Acids: The carbon atoms are joined together by one or more of these double bonds.

  • Monounsaturated: A FA with only one carbon to carbon double bond.

  • Polyunsaturated: A FA with more than one carbon to carbon bond

Physical Properties and Food Sources:

Saturated Fats:

  • Likely solid at room temp

  • Found usually in animal products

  • Also in tropical coconut, palm kernel oils, and cocoa butter,

  • More chemically stable than unsaturated seats

  • Become rancid slowly

  • Long shelf life

  • Table of food sources included

Unsaturated Fats:

  • Likely liquid at room temp

  • Plant origin

  • Rancid quickly

  • Examples: Corn, cottonseed, soybean, and sunflower oils.

Hydrogenation:

  • The process of adding hydrogen to a fat

  • Done to extend the fats shelf life or harder at room temp

  • Trans Fatty Acids: Produced by the partial hydrogenation of unsaturated veritable oils.

  • FDA regulates fewer than .5g per serving be allowed to claim 0 trans fats

  • Detrimental to health

  • List of foods with trans fats

Functions of Fats:

  • Fuel and vehicles for fat soluble vitamins

Fuel Source:

  • Major dietary source of fuel

  • Greater potential for release of energy with more carbon and less O2

  • Furnish twice as many cals g for g as CHO

  • 1g or fat is 9cals

Vehicle for Fat-Soluble Vitamins:

  • fats act as a vehicle for vitamins A,D,E, and K

Satiety Value:

  • Fats add flavor, value, and texture to foods.

  • They leave the stomach slower so you feel more full longer

Sources of Essential Fatty Acids:

  • Fats contain the essential fatty acids: linoleum, arachidonic, and linoleum acid.

  • Linolenic acid is sub divided into alpha and gamma, Also called omega-6


Fats in the Body:

  1. Supply fuel to most tissues

  2. Function as an energy reserve

  3. Lubricate body tissues

  4. Support and protect vital organs

  5. Insulate the body

  6. Form an integral part of cell membranes

  7. Serve as a carrier for the absorption of fat soluble vitamins

Fuel Supply:

Fuel Reserve:

Lubrication:

Organ Protection:

Insulation:

Cell membrane Structure:

Carrier for Fat-Soluble Vitamins:

Cholesterol:

  • Not a true fat but a sterol.

  • Body makes 1000mg a day mainly in the liver

Functions:

  1. A component of bile salts that aid digestion

  2. An essential component of all cell membranes

  3. Found in brain and nerve tissue and in the blood

  4. A precursor for the production of steroid hormones

  • Necessary in producing: Cortison, Adrenaline, Estrogen, and Testosterone

  • Hormone: Is a substance produced by the endocrine glands and secreted directly into the bloodstream

Food Sources:

  • Only found in animal foods

  • No one food is bad for containing cholesterol

Dietary Recommendations Concerning Fat:

  • Box 3.1 discusses the acceptable

Dietary Fat Intake and Health:

Key Points:

  1. The group name for all fats is lipid

  2. Hydrogen oxygen and carbon are the primary elements and fat

  3. Gram gram fats contain more than twice the calories of carbohydrates

  4. Fats are labeled according to the amount and type of fatty acids they contain as saturated, unsaturated, mono, saturated, poly unsaturated, and trans fatty acid

  5. Fats serve many important functions in our diets and our

  6. A balanced intake of carbohydrate and fat is essential for optimal health excess fats in our diet are associated with cardiovascular disease, obesity, diabetes, and some types of

  7. Cholesterol is a fat like substance that is present an animal food sources, and produced by

  8. Many Americans would benefit from decreasing their intake of saturated fat

  9. The national academic and science current dietary reference intake for macro nutrients recommends that adults consume between 20% and 35% of their

  10. Dietary guidelines for Americans recommends a saturated fat intake of fewer than 10% of all calories when consuming a healthy eating pattern each day.