ch. 6 nutrition


cheif fxn of fat


energy storage


Cushions skin
Thermoregulation -
insulation blanket to
reduce heat loss/maintain
body temperature
 Gives shape to the body
 Breasts
 Hips
 Tummy
 Thighs
 Buttocks


visible fat


In every cell membrane
Component of myelin
Brain tissue is rich in fat
Shock absorber to protect
organs
Constituent of hormones
and biochemicals
 Vitamin D
 bile


Invisible fat


Usefullness of fats in foods


palatabilitysatiety (stay full longer)better aroma


Fat soluable vitamins


ADEK


3 lipids


Triglycerides (fats and oils) Phospholipids Sterols


are lipids soluable in water?


no


are lipids soluable in organic compounds?


yes


Simple lipids


Fats � solid at room temperature Oils � liquid at room temperature Contain only fatty acids and glycerol


Fats that make adipose tissue and burn for energy
95% of all lipids in foods and the human body; chief form of fat in foods


Triglycerides


Act as tiny rowboats ferrying hormones and fat soluble vitamins through blood and across cell membranes


phospholipids


Fat and alcohol compounds with no calories
Structure similar to cholesterol
Ex: vitamin D, testosterone, cholesterol


Sterols


Breakdown of triglycerrides


three fatty acids and a glyceride


are triglycerides saturated or unsaturated?


both


fxns of tryglyccerides


Energy source and reserve Insulation and protection Carrier of fat-soluble vitamins


An organic compound, three carbons long Serves as the backbone for triglycerides


Glycerol


Organic acids composed of carbon chains
of various lengths
Each has an acid end and hydrogen
attached to all of the carbon atoms of the
chain
Differ on the basis of length and degree of
saturation


Fatty acids


Sources of omega-3 fatty acids



Soybean, canola, walnut, flaxseed oils Salmon, tuna, mackerel


Sources of omega-6 fatty acids



Vegetable oils Nuts and seeds


Every available bond from the
carbons is holding a hydrogen


Saturated fatty acid


Contains one point of
unsaturation


Monounsaturated fatty acid (MUFA)


Contains two or more points of
unsaturation


Polyunsaturated fatty acid (PUFA)


Contain only one double bond


MUFA


MUFA's do what to HDL, LDL, tryglycerides, and VLDL


increase HDL and lower the rest


Sources of MUFA's


Olive oil, canola oil, avocados, pecans, almonds, peanuts,peanut oil


Contain two or more double bonds


PUFAs


PUFA's found in


Corn oil, fish, nuts, seeds, canola oil, sunflower oil, safflower oil


What do PUFAs do to cholesterol and LDL


lower them


Omega-3 and Omega-6 fatty acids
belong to this family


PUFAs


Why are trans/cis fats added to food


to keep them from spoiling...resist oxidation


how much trans fat in margarin


50%


Component of cell membranes
 Lecithin and Sphingomyelin
 Lipid transport as part of lipoproteins
 Emulsifiers
Food sources
 Egg yolks, liver, soybeans, peanuts


phospholipids


Component of cell membranes
Precursor to other substances
 Sterol hormones
 Vitamin D
 Bile acids
 Glucocorticoids
 Synthesis
 Made in the liver
Food sources
 Found only in animal foods
 Forms major parts of plaques that narrow arteries in
atherosclerosis
 The underlying cause of heart attacks and strokes


Sterols


liver uses cholesterol for what?


bile production


cholesterol fxns


Structural component of all cell membranes Enables nerve cells to send/receive messages Precursor for sex hormones (estrogen and testosterone), aldosterone, and bile acids Building block for Vit D Enables gallbladder to make bile acids,digestive chemicals for fat and fat soluble vitamin absorption


Where can you get cholesterol?


animal products


the average person has how many fat cells?


40 billion


excess fat is stored in


lipocytes


Without CHO, the incomplete breakdown of fat produces ketones through


gluconeogenesis


With no gallbaldder what do you have to reduce


fat intake


split fatty acids from glycerol


Triglycerides


?%of dietary fat and ?% of dietary
cholesterol is absorbed


95%10-15%


Once absorbed into the lymphatic system, fats are packaged with protein into


chylomicrons


Chylomicrons transport triglycerides to fat depots in the.. (3)



Muscles Breasts Insulating fat layer under the skin


Serve as transport vehicles for lipids in blood and lymph


lipoproteins


major types of lipoproteins


chylomicrons, VLDLs, LDLs, and HDLs


Carry triglycerides and other lipids made in the liver to the body cells for their use


Very-low-density lipoproteins (VLDL)


Transport cholesterol and other lipids to body tissues
Made from VLDL


Low-density lipoproteins (LDL)


Carry cholesterol from body cells to the liver for disposal
 Acts like Pac-Man


High-density lipoproteins (HDL)


Lipoproteins and
Heart Disease Risk
Risk factors that cannot be changed 3



Increasing age Being male Family history of premature heart disease


Which raises blood cholesteral more, sat. food fats and trans fats or food cholesterol?


sat. food fats and trans fats


What is linoleic acid


omega 6


What is linolenic acid


omega 3


The only PUFA's that cannot be synethesized by the body


omega 3 and 6


eicosanoids
compounds that regulate body functions
Made by?


Omega 3 and 6


Provide raw material for eicosanoids
Serve as parts of cell membranes
Contribute lipids to brain and nerves
Promote normal growth and vision
Maintain outer structures of skin/protect from
moisture loss
Help regulate metabolism
Support immune cell functions


Linolenic and linoleic acid


Necessary for growth, reproduction,
and skin integrity
Essential fatty acid (must come from diet)
Found primarily in:
 Safflower oil, sunflower oil, corn oil,
sesame oil


omega 6


A polyunsaturated fatty acid
Can be used to produce other omega-3 fatty acids
Include eicosapentaenoic (EPA) and docosahexaenoic
(DCA) acids


omega 3


single greatest contributor
of saturated fat in the diet


cheese


Overconsumption of Fat is
Implicated in�


Obesity Hyperlipidemia (elevated blood lipids and triglycerides) Diabetes mellitus Fatty liver Some cancers  1/3rd of deaths due to cancer are attributed to diet and physical activity


effects of too little dietary fat


Fat malabsorption (cystic fibrosis, inflammatory bowel disease) Very low fat diets (<10% calories from fat) Premature infants Severe alcoholics Anorexics


Effects of Too Little Dietary Fat
Deficiency symptoms may occur after a few weeks



Dry, scaly skin Hair loss Impaired growth Impaired wound healing Visual impairment Impaired reproductive ability


Dietary guidlines for fat


Choose a diet that Provides 20%-35% of its calories from fat Keeps saturated fat intake below 10% of caloric intake Keeps trans fat intake below 1% of calories Substitute MUFA�s or PUFA�s for saturated and trans fat Contains fruits, vegetables, and whole grains