important source of energy for all cells and is the preferred energy for nerve cells
(fruits, veggies, and grains)
carbs
the most abundant carb and is produced by plants through photosynthesis
glucose
referred to as sugars and are made of one or two molecules
simple carbs
contain one molecule (glucose, fructose, galactose, and ribose)
monosaccharides
contain two molecules (lactose, maltose, and sucrose)
disaccharides
contain 3 to 10 monosaccharides
complex cards (oligosaccharides)
consist of hundreds to thousands of glucose molecules (starch, glycogen, and most fibers)
polysaccharides
the most abundant monosaccharide
glucose
the sweetest natural sugar
fructose
milk sugar
lactose
table sugar
sucrose
plants store carbs as ___________
starch
straight chain of glucose
amylose
branched chain of glucose
amylopectin
type of fiber composed of glucose molecules linked by beta bonds are largely indigestible (grains, legumes, fruits, veggies)
resistant starch
storage form of glucose for animals (humans) and is not found in food and therefore not a source of dietary carbs
glycogen
stored in the liver and muscles
glycogen
composed of long polysaccharide chains
fiber
non-digestible parts of plants
dietary fibers
non-digestible forms of carbs extracted from plants or manufactured in a lab that have known health benefits
functional fibers
Total fiber =
dietary fiber + functional fiber
type of fiber that dissolves in water and is viscous and gel-forming
soluble fibers
do not dissolve in water, non-viscous
insoluble fibers
regular consumption can reduce risk for cardiovascular disease and type 2 diabetes
soluble fibers
promote regular bowel movements, alleviate constipation, and reduce diverticulosis
insoluble fibers
digestion breaks down most carbs into __________________________
monosaccharides
enzyme that begins starch digestion in the mouth, breaks starch down into maltose
salivary amylase
carb digestion does not occur in the _____________
stomach
_______________ _________ inactivate salivary amylase
stomach acids
majority of carb digestion occurs in the _____________ __________________-
small intestine
enzyme produced in the pancreas and secreted into the small intestine and digests remaining starch to maltose
pancreatic amylase
additional enzymes in the microvilli digest disaccharides to monosaccharides
maltase
sucrase
lactase
absorbed in the mucosal cells lining the small intestine and then enter into the bloodstream
monosaccharides
glucose and galactose are absorbed via ____________ _________________
active transport
fructose is absorbed via ___________________ __________________
facilitated diffusion (slower absorption)
fructose and galactose are converted to _____________ in the __________
glucose, liver
what can provide immediate energy when in the bloodstream?
excess glucose
We do NOT have the enzymes to digest ________.
fiber
___________ remaining in the colon adds bulk to stool and is excreted in feces
fiber
hormones such as insulin, glucagon, epinephrine, norepinephrine, and cortisol help maintain what?
blood glucose levels in a narrow range
secreted by beta cells of the pancreas and stimulates glucose transporters to help move glucose form the blood across the cell membrane
insulin
secreted by alpha cells of the dances and stimulates the liver to convert glycogen to glucose
glucagon
secreted by the adrenal glands and nerve endings when blood glucose is low and are responsible for our "fight-or-flight" reactions in danger
epinephrine and norepinephrine
secreted by the adrenal glands to act on the liver, muscle, and adipose tissue
cortisol and growth hormone
increases gluconeogenesis and decreases glucose use by muscles and organs
cortisol
decreases muscle glucose intake, increases fatty acid mobilization and use, and increases liver glucose output
growth hormone
a food's potential to raise blood glucose
glycemic index
cause sudden surge in blood glucose, triggering a large increase in insulin, which may be followed with a dramatic fall in blood glucose
high glycemic index
cause low to moderate fluctuations in blood glucose
low glycemic index
used to determine the effect of a food on a person's glucose response
glycemic load
how is the glycemic load found?
grams of carbs in a food are x by the glycemic index
higher _________ foods help regulate blood glucose
fiber
each gram of carbs = __ kcal
4
red blood cells only use _____________ for energy
glucose
alternative fuel source for the brain
ketosis
breakdown of stored fat during fasting, low carb intake, or vigorous exercise forms _________________
ketones
excess ketones increase blood acidity (lower pH) and cause ___________________
ketoacidosis
sufficient energy from _________ prevents ketone production
carbs
occurs when the diet doesn't provide enough carbs
gluconeogenesis
may prevent chronic and digestive diseases (colon cancer, heart disease, type 2 diabetes)
fiber
RDA for carbs is ___________ grams/day but this is NOT enough to support daily activities (only enough for the brain)
130
AMDR is ________________ of daily calories
45-65%
contribute to tooth decay, high or low cholesterol levels, etc.
diets high is simple sugars
foods in which nutrients that were lost during processing have been added back so the food meets a specified standard
enriched foods
have nutrients added that did not originally exist in the food
fortified foods
Adequate intake for fiber
____ g for women
____ g for men
or ____ g fro every 1,000 kcal per day
25
38
14
limited use is not harmful and comes in many forms
non-nutritive sweeteners
condition in which the body can no longer regulate normal glucose levels, and hypoglycemia occurs
diabetes
higher than normal levels of blood glucose
hypoglycemia
diabetes that occurs during pregnancy
gestational diabetes
accounts for 10% of diabetes cases and most cases are diagnosed in adolescence
type 1
body does not produce enough insulin and causes hyperglycemia
type 1
is classified as an autoimmune disease and requires insulin injections
type 1
_______________ can trigger a cascade of changes resulting in diabetes
obesity
Cells become less responsive to insulin
insulin insensitivity (insulin resistance)
higher than normal blood glucose
impaired fasting glucose (pre-diabetes)
a cluster of risk factors that increase the risk for type 2 diabetes
metabolic syndrome
low blood glucose that may cause shakiness, sweating, anxiety, and weakness
hypoglycemia
pancreas secretes too much insulin after a high-carb meal
reactive hypoglycemia
pancreas produces too much insulin, even when someone has not eaten
fasting hypoglycemia
insufficient production of lactase to digest lactose-containing foods (GI symptoms: gas, cramping, etc.)
lactose intolerance
recommended in moderation
alcohol
Amount of beverage that provides approximately 0.5 fl. oz of pure alcohol
drink
absorbed directly from the stomach and small intestine then transported to the liver to be metabolized
alcohol
the liver becomes more efficient in its breakdown of alcohol
metabolic tolerance
individuals show few signs of impairment/intoxication, even at high BAC
functional tolerance
a pattern of alcoholic consumption resulting in distress, danger, or harm to one's health, functioning, or relationships
alcohol abuse
consuming 5 or more alcoholic beverages on one occasion for men and 4 for women
binge drinking
a disease characterized by chronic alcohol dependence
alcoholism
symptoms include: craving, loss of control, physical dependence, tolerance ( the need to drink more)
alcoholism
alcohol acts as a sedative, depressant
narcotic effect
high concentrations destroy cells
toxicity risk
lasts up to 24 hours and symptoms include headache, fatigue, nausea, vomiting, extreme thirst, etc.
alcohol hangover
serious metabolic response to vey high intakes and reduces oxygen level reaching the brain; can result in death from respiratory or cardiac failure
alcohol poisoning
causes reduced liver function and increased risk for chronic disease
alcohol abuse
causes malformations of developing fetus' face, limbs, heart, or nervous system (effects are permanent)
fetal alcohol syndrome
diverse group of molecules that are insoluble in water
lipids
the lipid content of diets and foods
fats
the 3 types of lipids found in foods and in body cells and tissues:
triglycerides
phospholipids
sterols
the most common food based lipid and contain three fatty acids and one glycerol molecule
triglycerides
fatty acids are classified by are classified by the type of fatty acids attached to the __________________ ________________.
glycerol backbone
fatty acids can vary by...
carbon chain length
saturation level
shape
6 or less carbon atoms
short-chain fatty acids
6-12 carbon atoms
medium-chain fatty acid
14 or more carbon atoms
long-chain fatty acids
carboxyl end
alpha- carbon
methyl end
omega- carbon
fatty acid chain ____________ determines method of lipid digestion, absorption, metabolism, and use
length
have hydrogen atoms surrounding every carbon in the chain (no double bonds)
saturated fatty acids
lack one hydrogen atom (on double bond)
monounsaturated fatty acids
fatty acids have more than one double bond
Polyunsaturated
form straight, rigid chains, packed tightly together and are solid at room temp.
saturated fatty acids
have kinked fatty acids at double bond and do not pack together tightly and are liquid at room temp.
unsaturated fatty acids
hydrogen atoms are added to unsaturated fatty acids, create trans fatty acids
hydrogenation
cannot be made by the body and must be obtained from food
essential fatty acids
omega-6 fatty acid found in vegetable and nut oils
linoleic acid
omega-3 fatty acid found in vegetables, soy, flaxseeds, and walnuts
alpha-linolenic acid
____________________ contain glycerol backbone, two fatty acids, and a phosphate group
phospholipids
soluble in water and assist in transporting fats in the bloodstream
phospholipids
combine with bile salt and electrolytes to make bile (manufactured in our bodies)
lecithins
contain multiple rings of carbon atoms
sterols
cholesterol is found in animal-based foods as ________________________ ____________
cholesterol esters
___________________ is made in the liver and is not necessary in the diet
cholesterol
fat digestion begins in the ___________ _________________
small intestine
bile is produced in the _________ and stored in the __________________
live, gallbladder
emulsifies fat into small droplets
bile
capture lipid digestion products and transport them to the enterocyte for absorption
micelles
transport lipids into the bloodstream
lipoproteins
lipoproteins produces in the enterocyte to transport lipids from a meal and are soluble in water
chylomicrons
transported out of the enterocyte and then travels through the lymphatic system, and is transferred to the bloodstream through the thoracic duct
chylomicrons
what are absorbed more quickly since they are not arranged into chylomicrons?
short and medium chain fatty acids
triglycerides in chylomicrons must be disassembled by ________________ _________ before they can enter body cells
lipoprotein lipase
what can triglycerides in body cells be used for?
used immediately for energy
used to make lipid-containing compounds
stored in muscle and adipose tissues
roles of fat
____________ density
major fuel at ________
_________________ exercise
_____________ energy
essential _________ _________
fat-soluble _________________
regulates _________ function
maintained ________________
_______________ the body
provides
energy
rest
endurance
stored
fatty acids
vitamins
cell
protects
flavors, textures
satiated
AMDR of fat is ________________ of calories
20-35%
fats we add to foods (butter, cream, mayo, salad dressings)
visible fats
fats hidden in our foods (baked goods, dairy, meats, fast foods)
invisible fats
used to lower fat content of foods
fat replacers
leading cause of death in the US
heart disease
increases the risk for heart attack or stroke
hypertension
decrease the removal of LDLs from the blood, increase blood cholesterol levels, and contribute to the formation of plaques that can block arteries
diets high in saturated fats
can raise blood levels of LDL cholesterol as much as saturated fat, and are abundant in hydrogenated vegetable oils
diets high in trans fatty acids
endogenous cholesterol synthesis inhibitors
statins
medicines to help reduce risk of cardiovascular disease
statins
bile acid sequestrates
nicotinic acid (not good)
what three cancers have been studied for their possible link to dietary fat intake?
breast cancer
colon cancer
prostate cancer
large, complex molecules found in tissues of all living things, dictated by DNA
proteins
contain carbon, hydrogen, and NITROGEN; made from 20 amino acids
proteins
cannot be produced in sufficient quantities to meet physiological needs and must be obtained from food
nine essential amino acids
can by synthesized in sufficient quantities within the body
eleven nonessential amino acids
transfer amine group from an essential amino acid to a different acid group and side chain
transamination
occurs when a nonessential amino acid becomes essential
conditionally essential amino acid
tyrosine becomes a conditionally essential amino acid that must be provided by the diet
phenylketonuria (pku)
proteins are long chains of?
amino acids
join amino acids together forming dipeptides, tripeptides, oligopeptides, and polypeptides
peptide bonds
the process by which cells use genes to make proteins
gene expression
the segment of DNA that serves as the template of the synthesis of a particular protein
gene
made up of chemical compounds and proteins that can attach to DNA and direct such actions as turning genes off, and controlling the production of proteins in particular cells
epigenome
messenger RNA copies the genetic info from DNA in the nucleus
transcription
the genetic info carried by mRNA is translated into the amino acid sequence of a protein at the ribosome
translation
existing proteins are degraded to provide the building blocks for new proteins
protein turnover
includes amino acids from food and cellular breakdown
amino acid pool
protein organization determines ______________
function
spiral shape from twist in amino acid chain
secondary structure
unique three-dimensional shape maintained by hydrogen bonds and disulfide bridges; determines protein's function
tertiary structure
polypeptides bond to form larger proteins
quaternary structure
proteins uncoil and lose their shape (function is lost; heat, acid, base, heavy metal, alcohol)
protein denaturation
for ______________ _____________, all essential amino acids must be available to the cell
protein synthesis
essential amino acid that is missing or in the smallest supply
limiting amino acid
insufficient essential amino acids
incomplete protein (low quality)
sufficient amounts of all nine essential amino acids (derived from animal and soy protein)
complete protein (high quality)
combine two or more incomplete protein sources to make a complete protein
mutual supplementation
two or more foods are combined to supply all nine essential amino acids for a complete protein
complementary protein
protein digestion begins in the ________________-
stomach
enzyme that begins breakdown of proteins into short polypeptides and amino acids
pepsin
hormone that controls hydrochloric acid production and pepsin release
gastrin
complete protein digestion
proteases
cells of the small intestine have different sites that specialize in transporting certain types of amino acids, dipeptides, and tripeptides
special sites
comparison of the amount of the limiting amino acid in a food to the amount in a reference food
chemical score
used to calculate a value for protein quality
protein digestibility corrected amino acid score
__________ protein and many soy products are highly digestible (90% absorption)
animal
functions of proteins
_______ growth, repair, and maintenance
enzymes and _______________
fluid and electrolyte _____________
acid-base __________________
_________________ system
____________ source
nutrient _______________ and _____________
neurotransmi
cell
hormones
balance
balance
immune
energy
transport, storage
blood
determines protein needs
nitrogen balance
consuming more nitrogen than is excreted (during times of growth or pregnancy, recovery)
positive nitrogen balance
excreting more nitrogen than is consumed (starvation or low-energy diets)
negative nitrogen balance
intake equals excretion
in nitrogen balance
recommended percentage of energy is ______ of total energy intake from protein
10-35%
high protein diets of mostly animal sources are associated with higher blood cholesterol levels, which often leads to?
heart disease
high protein diets can increase risk of ____________ __________ is susceptible people
kidney disease
restricting the diet to foods of plant origin
vegetarianism
disorder caused by inadequate protein and energy intake
protein-energy malnutrition
grossly inadequate energy, protein, and nutrient intake (anemia)
marasmus
disease resulting from low protein intake (distention of the belly)
kwashiorkor
phenylketonuria, sickle cell anemia, and cystic fibrosis are all examples of ?
genetic disorders caused be defective DNA