I G Energy & Macronutrients (CHO, PRO, FAT) Flashcards
glycolysis vs. gluconeogenesis vs. glycogenesis vs. glycogenolysis**
- glycolysis = glucose –> pyruvate or pyruvic acid for use in Krebs cycle
- gluconeogenesis = conversion of NON-CHO sources into GLUCOSE (from GLYCEROL, AAs)
- glycogenesis = glucose –> glycogen or storage form
- glycogenolysis = glycogen (stored form) –> glucose
the brain uses _____ exclusively as an energy source; uses _____ during starvation**
- glucose = energy source
- ketone bodies = starvation
tissue stores of glucose
- GLYCOGEN - muscle and liver
- fat from adipose tissue
- cellular mass (protein stores)
what is gluconeogenesis?**
conversion of NON-CHO sources INTO GLUCOSE from GLYCEROL AND AMINO ACIDS
homeostasis
state of equilibrium of the internal environment of the body
enzymes are what type of compound?***
PROTEINS
enzymes
organic catalysts that control reactions
what are coenzymes?
enzyme activators; include some vitamins
what coenzymes are needed for energy production?**
1) pantothenic acid
2) thiamin (B1)
3) riboflavin (B2)
4) niacin (B3)
substrate
substrate = substance upon which an enzyme works
cofactor
assist enzymes, minerals
what are hormones?
secretions from endocrine glands, chemical messengers that trigger enzymes
what hormone regulates metabolism and the rate of oxidation?
THYROXINE - influences physical and mental growth
thyroxine stimulates what 2 processes?
liver glycogenolysis (glycogen –> glucose) and gluconeogenesis (creation of glucose from non-CHO sources) = raises blood sugar
anabolism
synthesis of a more complex substance
catabolism
breakdown, uses and releases energy; creates a constant energy deficit which must be supplied by food
3 components of total energy expenditure***
1) basal energy expenditure (BEE)
2) energy expended in physical activity
3) thermic effect of food (TEF)
basal energy expenditure
minimum amount of energy needed at rest in fasting (amount needed to carry out involuntary work of the body, activity of internal organs, internal temperature)
basal energy expenditure is affected by?**
- temperature (hot = 5-20% increase)
- caffeine
- alcohol
- nicotine (all increase 7-15%)
energy expended in physical activity is AKA?
activity thermogenesis
thermic effect of food
energy needed to digest, absorb, and assimilate nutrients (diet-induced thermogenesis or the calorigenic effect of food)
thermic effect of food is greater after what types of nutrients?**
greater after consumption of carbohydrate and protein than after fat
most variable part of total energy expenditure?
physical activity
what is the basal metabolic rate? when is it measured?
measured in morning when reclining, awake, relaxed, at normal body temperature, at least 12 hours after last meal, and several hours after strenuous activity
what does the BMR measure?
oxygen consumed
BMR is primarily affected by?
sex, age, body composition, endocrine glands (thyroid)
how does sex affect BMR?
women have 5-10% lower BMR than men
highest BMR is at what age?***
0-2 y/o
how does old age affect BMR?
less activity, less lean body mass and more body fat = lower BMR
what is PBI? what does it measure?***
protein bound iodine = measures activity of thyroid gland, therefore energy metabolism
associated hormones with PBI
thyroxine (T4) and triiodothyronine (T3)
relationship between PBI and BMR***
when PBI is elevated, BMR is elevated
when is BMR elevated?**
- GROWTH
- PREGNANCY
- LACTATION
- FEVER
- CA & HTN
how much does BMR rise with a fever?***
7% increase for each degree rise in temperature (98.6 is a normal temperature)
BMR can be increased by?
exercise
what is RMR?
resting metabolic rate: energy expenditure measured under similar conditions to BMR after a short rest and controlled intake of caffeine and alcohol
which is more frequently measured - BMR or RMR?***
RMR
what equation BEST predicts closest to indirect calorimetry? (within 10%)***
MSJ (Mifflin St. Jeor)
who should you use the MSJ equation with?***
NORMAL and OBESE individuals
what is the most PRACTICAL way of measuring ENERGY BALANCE?***
following changes in weight
direct calorimetry***
measures heat produced IN a respiration chamber
indirect calorimetry***
measures OXYGEN CONSUMED and CO2 excreted using a PORTABLE MACHINE
benefits of indirect calorimetry?***
PRACTICAL WAY of measuring which nutrients are being used for energy
indirect calorimetry is useful for?***
ATHLETE & CRITICALLY ILL
what is the respiratory quotient?
shows what type of fuel is being metabolized (CO2 expired/oxygen consumed)
RQ for CHO alone***
1
RQ for mixed intake**
0.85
RQ for fat alone
0.7
to decrease RQ, what should be done with nutrient intake?**
INCREASE fat intake
monosaccharides
glucose, fructose, galactose
disaccharides
sucrose, lactose, maltose
name the monosaccharides the following are made of:
- sucrose
- lactose
- maltose
- sucrose = glucose + fructose
- lactose = glucose + galactose
- maltose = glucose + glucose
polysaccharides & examples
complex - starch, cellulose, pectin, glycogen, dextrin
starch is?
glucose chains - 50% of CHO intake
cellulose is?
resistant to digestive enzyme amylase; adds bulk
pectin is?
nondigestible; thickening quality; found in fruits
glycogen is?
animal starch, from glucose; stored in muscle and liver
dextrin is?
intermediate product of starch breakdown
what is sorbitol?
alcohol from glucose
absorption of sorbitol***
absorbed MORE SLOWLY than GLUCOSE by passive diffusion
problem with excess sorbitol***
excess may cause DIARRHEA
carbohydrates in order of sweetness**
1) fructose*** (FIRST/SWEETEST)
2) invert sugar –> sucrose –> glucose –> sorbitol –>
3) mannitol –> galactose –> maltose –> lactose
functions of carbohydrates
- energy
- protein-sparing action (allows PRO to be used for tissue synthesis)
- regulation of fat metabolism - carbohydrate restriction leads to ketosis
chemical makeup of proteins
carbon, hydrogen, oxygen, nitrogen, sulfur
what element comprises most of proteins?**
nitrogen = 16%
what is an amino acid?
an amino group (NH2) as the base + a carboxyl group (COOH)
essential AA are?** (NAME THEM ALL)
TV TILL PMH
- threonine
- valine
- tryptophan
- isoleucine
- leucine
- lysine
- phenylalanine
- methionine
- histidine
what are essential amino acids?
INDISPENSABLE, needed for WOUND healing
what AA are essential during catabolic stress?***
arginine, glutamine
________ (AA) is a precursor for serotonin and niacin
tryptophan
phenylalanine is converted to __________; methionine is converted to _________
- phenylalanine –> tyrosine
- methionine —> cysteine
what is a complete protein?***
ALL essential amino acids in sufficient quantity and ratio to maintain body tissues and promote growth
what is HBV?***
high biological value = aka complete AA
what type of proteins should be given in a low protein diet?**
give mostly HBV = 75%
incomplete protein
deficient in one or more essential amino acids
simple protein
amino acids
conjugated protein vs. derived protein
- conjugated = simple + non-protein substance (ex: lipoprotein)
- derived = fragments from simple and conjugated (peptide)
sources of protein
meat, poultry, fish, eggs, milk, legumes
can proteins function as an energy source?***
inefficient energy source- nitrogen must be removed first (58% of protein can be converted to glucose)
functions of protein
tissue synthesis, maintains growth, regulates body processes
diet requirements for protein
0.8 g/kg body weight (10-15% total intake)
soybeans are low in what AA?
methionine
quality of soy protein
equivalent in protein quality to animal protein
legumes are low in what AA?
methionine, cystine, tryptophan
gelatin - low in what AA? has NO of AA?*
- low = methionine, lysine
* **HAS NO TRYPTOPHAN
simple fat
triglycerides = 3 FA + 1 glycerol
phospholipids**
- in cell membranes
- control what passes IN and OUT of cell
- functions in transport and utilization of FA and cholesterol through enzyme LCAT (lecithin cholesterol acyltransferase)
what are saturated fatty acids?***
single bonds, all are filled with HYDROGEN; solid and hard at room temperature
unsaturated fatty acids
one or more double bonds
monounsaturated vs. polyunsaturated
- mono = one double bond
- poly = 2 or > double bonds
most polyunsaturated oil? most unsaturated oil?**
- polyunsaturated = safflower
- unsaturated = canola
linoleic vs. linolenic acid***
- linoleic = omega 6
- linolenic = omega 3
deficiency of omega 6 will result in?**
POOR GROWTH RATE
- also eczema, petechiae
if linoleic acid replaces CHO, what happens?***
lower LDL and higher HDL
if linoleic acid replaces saturated fat, what happens?***
total cholesterol decrease, lower HDL
best source of linoleic acid?***
safflower
function of omega 3s***
- BRAIN DEVELOPMENT
- retinal function
deficiency of omega 3s results in?
neurological changes- numbness, blurred vision
main sources of linolenic acid***
FISH OILS (EPA eicosapentaenoic acid, DHA docosahexaenoic acid), WALNUTS, FLAXSEED, CANOLA
effects of linolenic acid on lipid profile**
- DECREASES hepatic production of TGs (inhibits VLDL synthesis)
- LITTLE EFFECT on total cholesterol levels
structure of fatty acids***
straight hydrocarbon chains terminating in a carboxyl group (COOH) at one end and a methyl group (CH3) at the other end
what does the omega sign designate?**
location of the first double bond counted from the METHYL end
what is hydrogenation?
process of adding hydrogen (at the double bond) to unsaturated fatty acids to increase saturation and stability
what are trans fatty acids?
hydrogens are across from each other, packed tightly; intake could influence membrane fluidity and could be harmful to function
where are trans fatty acids found?***
margarines, shortenings, frying fats (as partial hydrogenation of PUFA)
cis fatty acids
(also a product of hydrogenation) hydrogens are on the same side of the double bond
BEST source of saturated fats***
1) coconut oil
THEN in order or predominance:
palm kernel –> cocoa butter –> butter –> beef tallow –> palm oil
what are MCTs?
medium-chain triglycerides –> saturated fatty acids between 6-12 carbons found in milk fat, coconut oil, palm kernel oil
BEST sources of monounsaturated fats?***
1) olive
THEN: canola –> peanut –> sunflower
BEST sources of polyunsaturated fats?***
1) safflower
THEN: corn –> soybean –> cottonseed –> sunflower
BEST sources of fats in butter? margarine?**
butter: SAT, MUFA, PUFA
margarine: PUFA, MUFA, SAT
functions of fat
energy, insulation and padding
function of fat in digestion***
fat DEPRESSES GASTRIC SECRETION, THEREFORE delaying emptying
why does fat provide more energy than carbs or protein?***
has less oxygen, MORE CARBON ATOMS FOR OXIDATION
alcohol energy
7 kcal/g
kcal from alcohol
.8 x proof x ounces
–AND–
proof = % alcohol x 2
what are winterized oils? properties?***
- found in SALAD DRESSINGS
- DO NOT CRYSTALLIZE WHEN COLD
color of winterized oil?***
CLEAR NOT CLOUDY
types of winterized oils
corn, soy, cottonseed; NOT olive
