Ch. 6 Lipids
Added fats and oils
provides most calories for Americans
classification
contain Carbon, Hydrogen, Oxygen
Two classes of water insoluble substances
simple lipids (triglycerides) - occur in food and body
structural lipids: produced by body for specific functions
chemical structure
short-chain fatty acids - less than 6 carbons
medium-chain fatty acids - 6 to 10 carbons
triglyceride = glycerol + three fatty acids
long-chain fatty acids - 12 or more carbons
diglyceride = glycerol + two fatty acids
monoglycerides = glycerol + one fatty acid
fatty acids
most saturated fatty acids - solid at room temp
short chain fatty acids - liquid at room temp (oils)
milk fat - large # of short chain saturated fatty acids
phospholipids
phosphourous and nitrogenous base + fatty acids and glycerol
fat absorption and transport of fats in blood
lecithin - most widely distributed
cephalin - necessary for blood clotting
lipoproteins
transports insoluble fats in bloods
compound lipids composed of: triglycerides, phospholipids, and cholesterol combined with proteins
4 different types: HDLs, LDLs, VLDLs, chylomicrons
physiologic roles
palatability
complementary relationships
satiety value
fat storage
energy
dental health
dietary fats essential for oral health, incorporated into tooth structure
oral food retention reduced by fat intake
delay gastric emptying
bacteria from dental plaque biofilm can cause blood clots
overconsumption
blood lipid levels (hyperlipidemia)
cancer - possible link to high fat diet, but research continues
obesity - excessive fat stores is a common disorder
Ch. 7 Metabolism and Balance
role of liver in metabolism
detoxifies drugs
glycogen can be broken down into glucose and released into the circulating blood as needed
regulation
role of kidneys in metabolism
controls nutrients in blood
filtration and reabsorption
removes waste products from the blood
helps maintain nutrient balance in body
carbohydrate metabolim
hyperglycemia - high blood glucose
hypoglycemia - low blood glucose
liver closely monitors glucose levels
glycemic index (GI) measures the effect of different carb foods on BG levels
monosaccharides transported through portal vein to the liver for glycogenesis
lipid metabolism
lipolysis breaks down fat
oxidation process of hydrolyzing triglycerides to enter Krebs cycle for energy production
lipogenesis converts glucose to fat
carbohydrates play a dominant role in heavy exercise when the muscle's oxygen supply is limited
liver regulates fat metabolism
metabolic interrelationships
excessive intake of nutrients results in excess energy being stored as adipose tissue
catabolism involves oxidation through TCA cycle to produce energy
fat is good source of energy, but carbs is preferred fuel
energy production
ATP - instant source of cellular energy for mechanical work; transport of nutrients and waste products, and synthesis of chemical compunds generated from the Krebs cycle
Basal Metabolic Rate (BMR)
energy required for involuntary physiologic functions to maintain life (respiration, circulation, and maintenance of muscle tone and body temp
can be measured in clinical setting using indirect calorimetry
amount of energy required when the body is in postabsorptive state
factors affecting BMR
age
pregnancy and lactation
sleep
surface area
state of health
body composition and gender
endocrine glands: chemical messengers
temperature
fasting and starvation