Vitamins (Exam 1) Flashcards
Are vitamins found in nature?
yes
Are vitamins essential or nonessential?
essential!!!!
Do vitamins yield energy?
no but they do help reactions that do yield energy
The discovery of ___________ gave birth to the field of nutrition
vitamins
Are vitamins coenzymes or cofactors?
coenzymes (cosubstrate or prosthetic group)
Are minerals coenzymes or cofactors?
cofactors
Can you have too many vitamins?
yes
Too much vitamin C may cause chronic ____________
diarrhea
Too much vitamin B6 leads to irreversible _______ damage
nerve
Vitamers are the multiple forms of vitamins. Different vitamers have different bioavailability. In general, vitamers of synthetic forms of vitamins have less bioavailability than nature vitamer forms. What is the exception?
folate (vitamin B9) has higher bioavailability in synthetic form
this is not a good thing bc it can change uracil to thymine and fuel tumors if folate is overactive in the body
What are the fat soluble vitamins?
KADE
Vit K, A, D, and E
Fat soluble vitamins dissolves in fats and usually are found in fats and _______ of food
oil
(so eating a fat free diet or taking meds that strip the fat soluble vitamins makes you deficient in KADE vitamins)
Fat soluble vitamin absorption is increased with what?
dietary lipids (so best to take fat soluble vitamins after you eat)
How are fat soluble vitamins transported in the body?
like fat in chylomicrons, VLDL, LDL or binding proteins
Can fat soluble vitamins be stored in the body?
yes, it tends to be found in lipid portions of a cell but if theres too much it may cause toxicities
Fat soluble vitamins leave the body through?
feces
If fat soluble vitamin absorption mechanism is defective, then deficiency is likely. What are some causes of defective fat soluble absorption?
-fat malabsorption
-drug or alcohol abuse
-intestinal diseases like Crohn’s disease
What are the water soluble vitamins?
all the vitamin B vits + C
1) vit C
2) thiamin (vit B1)
3) riboflavin (vit B2)
4) niacin (vit B3)
5) pantothenic acid (vit B5)
6) pyridoxine (vit B6)
7) biotin (vit B7)
8) folate/ folic acid (vit B9)
9) cobalamin (vit B12)
What is the other name for thiamin?
vit B1
What is the other name for riboflavin?
vit B2
What is the other name for niacin?
vit B3
What is the other name for pantothenic acid?
vit B5
What is the other name for pyridoxine?
vit B6
What is the other name for biotin?
vit B7
What is the other name for folate?
folic acid or vit B9
What is the other name for cobalamin?
vit B12
Which vitamin synthesizes hydroxyproline?
vit C
Which vitamin is involved in decarboxylation reactions?
thiamin/ vit B1
Which vit makes FAD?
riboflavin/ vit B2
Which vit makes NAD (oxidation rxns) and NADPH ((reduction rxns)?
niacin/ vit B3
CoA requires which vit?
vit B5/ pantothenic acid
Which enzyme converts OAA to citrate in TCA?
citrate synthase (this enzyme requires vit B5/ pantothenic acid)
Which vitamin is required for transamination reactions with ALT and AST (aminotransferases)?
Pyridoxine/ vitamin B6
Which vitamins are needed to increase homocysteine (can change back to AAs in the body)?
1) pyridoxine (vit B6)
2) folate (folic acid, vit B9)
3) cobalamin (vit B12)
Which vitamin is required for carboxylation reactions?
Biotin/vit B7
Which vitamin is a carbon donor?
Folate/folic acid/vit B9
Which vitamin is used in RNA and DNA biosynthesis?
Folate/folic acid/ vit B9
Which vitamin is required for odd chain catabolism?
Cobalamin/vit B12
Are water soluble vitamins coenzymes or cosubstrates?
Coenzymes
Are water soluble vitamins absorbed passively, actively, or both?
Both
Are water soluble vitamins transported freely, by carriers, or both?
Both
Most water soluble vitamins can be stored with an adequate amount. What are the exceptions?
Vit B9 and 12
Water soluble vitamins usually don’t have toxicity. What are the exceptions?
Vit B1, B3, B6, B9, and C
How are excess water soluble vitamins removed from the body?
Excreted in urine
Substantial amounts of vitamins are lost by the time a fruit or vegetable is picked, transported, stored, prepared, and cooked. The water soluble vitamins especially ___________________ can be destroyed with improper storage and excessive cooking
thiamine, vit C, and folate
How should you store fruits and veggies with thiamine, vit C, and folate in them?
In a dark cold place
Heat, light, exposure to air, and cooking are all factors that can destroy vitamins, especially vit….
B2
How should you prepare fruits with vit B2?
Wash them and then cut them
What is the best method to preserve vitamins if foods are not eaten freshly picked?
Freezing
Performed vitamin A is the active form. What are the names for active vit A?
Retinoids (retinal, retinol, retinoic acid)
Which vit A important for vision?
Retinal
Which vitamin A are the lipid hormones?
Retinol and retinoic acid
Active vit A is found in what products?
Animal products only
What is the proformed (inactive form or precursor form) of vit A?
Carotenoids (beta or alpha carotene)
Which carotenoids do NOT have vit A activity?
Lutein and lycopene
Spinach is rich in what carotenoid and is known to improve or prevent age related chronic eye diseases?
Lutein
Proformed vit A (carotinoids) must be converted to what form?
Preformed vit A (retinoid form)
What cells in the body can split carotene (inactive form) into two molecules of retinoids (active form of vit A)?
Intestinal cells
Proformed vit A/ carotenoids are found in what products?
Plant products
The enzymes that converts 1 beta carotene into 2 molecules of retinal is found where?
Small intestine or liver cells
Which vitamin A is the storage form?
Retinol
What is the major preformed/active vit A in the food?
esterified retinol (retinyl-ester)
Hydrolyzing retinyl-ester from FAs creates….
vit A
Hydrolyzing retinyl-ester from FAs creates vit A. What is required from the body here?
-bile
-digestive enzymes
-micelles
(dependent on the fat in diet)
What percentage of retinoids can be absorbed into the body?
90%
Intestinal cells can convert carotenoids to retinoids which are then absorbed and transported via ______________ to the __________
chylomicrons, liver
Which organ stores 50-80% of vit A in the body?
test q
liver
(storage in liver should last several months)
How is retinol transported out of the liver to target tissue?
retinol-binding protein
Carotenoids can be transported via ___________ to target tissue
VLDLs
Retinol can be esterified for storage or….
oxidized into retinal and then into retinoic acid
Which vitamin is found structurally in the visual pigments rods and cones?
retinal
Rhodopsin has a protein called __________ attached to 11-cis retinal, which binds to light to absorb protein
opsin
Rods and cones are found in what part of the eye?
retina
Which visual pigment is responsible for vision under bright lights and translates objects to color vision?
cones
Which visual pigment is responsible for vision in dim lights and translates objects to black and white vision?
rods
What is the 1st sign of vit A deficiency?
night blindness
In the visual cycle, rhodopsin absorbs the photon of light and cis-retinal isomerize to trans-retinal. Trans-retinal separates from opsin. Opsin triggers a reaction cascade message and is sent to brain and a cessation of dark current. In the dark, trans-retinal enzymatically converts back to cis-retinal. Opsin and cis-retinal enzymatically combine to regenerate ____________
rhodospin
Retinoic acids and retinol act like a hormone to affect….
gene expression
Retinoic acids and retinol can travel to the nucleus of cells and bind to _____________ receptors on the gene and allow stimulation or inhibition of the gene
retinoic
Retinoic acids and retinol are involved in ______________ synthesis and are necessary for cell aggregation and cell recognition
glycoprotein
note: this can prevent cancer
Which vit A is essential for normal reproduction?
retinol
(if theres not enough then there will be impaired embryonic development and can lead to spontaneous abortion)
Which vit A is critical for bone development and function bc it stimulates the synthesis of osteocalcin in osteoblast cells?
retinoic acids (note: vit A, K, and D are all important for this)
What 3 vitamins are important for bone development?
vit A, K, and D
Which vit A is important for immune function (mucus formation) and is known as an anti infection vit bc of its role in mucus formation?
retinoic acids and retinol
Which vitamins have antioxidant activity?
vit A, C, E, and s (selenium)
Retinoids have a role in cell development and immune system. Increased retinoids would lower the risk of epithelial type cancers, especially…
breast, lung, and prostate cancer
Are megadoses of vit A recommended?
NO it can be extremely harmful especially to smokers it can increase chances of lung cancer, but eating foods with vit A and phytochemicals will help as opposed to supplement)
What are the food sources for preformed/active vit A?
-liver
-fish oils
-milk
-eggs
(contributes to half of all the vit A intake)
What are the food sources for proformed vit A/carotenoids?
-dark leafy greens
-yellow-orange vegetables and fruits
Are vitamin A supplements necessary?
no
What is the fancy word for night blindness?
nyctalopia
Which vitamin is required for the visual process?
vit A
Deficiency of what vitamin leads to the inability to regenerate visual pigments?
vit A
What is xerophthalmia?
-pathological dryness of the conjunctiva and cornea
-if left untreated then it can lead to irreversible blindness
-decreased mucus production leads to bacterial invasion in the eye
-providing a megadose of vit A to an “at-risk” patient population can prevent blindness caused by xerophthalmia
What is follicular hyperkeratosis?
-keratin protects the inner layers of the skin and maintains moisture
-keratinized cells replace the normal epithelial cells in the underlying skin layers
-hair follicles become plugged, leading to bumpy, rough, and dry skin
-basically matures cells and overproduces keratin
-result of vit A deficiency
Follicular hyperkeratosis is the result of which vitamin deficiency?
vit A
Eating a whole polar bear liver can give you a toxic amount of which vitamin?
vit A
What is the acute form of vit A toxicity?
-usually eating too many animal products
-ingestion of LARGE doses of vit A within a short period
-ex: a whole polar bear liver (bc polar bears eat a lotttttttt of fish)
-will result in intestinal upset, headache, blurred vision, and muscular incoordination
-will also form pseudo tumor cerebri which is a fake tumor in the brain and increases pressure in the skull
Which vit A toxicity causes pseudo tumor cerebri?
acute toxicity (animal form)
What is the chronic form of vit A toxicity?
-caused by large intake of synthetic form of vit A over a long period of time
-bone and muscle pain
-loss of appetite
-skin disorders
-headache
-dry skin
-hair loss
-increased liver size
-vomiting
-increased risk of hip fractures
-discontinue supplement is recommended
-possible permanent damage to the liver
Which vitamin can cause this toxicity?
-teratogenic
-excessive vit usage can produce physical defects in fetus development
-spontaneous abortions or birth defects
-this vit is used to treat severe acne so a pregnancy test must be taken before, during and after treatment
vit A
What is hypercarotenemia?
-high amounts of carotenoids in the bloodstream
-excessive consumption of carrots/squash/beta-carotene foods turn the skin a yellow orange color
-this is not harmful bc carotenoids are the inactive form of vit A
Which vitamin is recommended to take in a supplement for everyone because 75% of the American population is deficient, especially people with darker skin color?
vit D
Which vitamin is known for strong bones while also preventing DM and cancers?
vit D
Early in the 20th century, it was shown that a fat soluble factor could prevent rickets in the diet or body exposure to UV light. The emphasis was placed on the dietary factor; therefore, any compound with a curative action on rickets was designated as vit _____
D
Vit D is an essential hormone needed for normal ______________ homeostasis. Through the years, it has been associated with skeletal growth and strong bones
calcium/phosphate
Vitamin D is a steroid hormone derived from….
cholesterol
Vitamin D comes from 2 sources. What are they?
endogenous (cholesterol through skin during sun exposure) and exogenous (through diet)
Which UV can penetrate glass?
UVA (UVB cannot)
To get vit D through the skin, what UV do you need- UVA or UVB?
UVB
Skin has to be exposed to sunlight (ideally in 60 degrees F or more) directly to make vit D, but UVB also causes sunburn so its best to go outside in the morning. What is the difference between light and dark skin tones here?
light skin people need 15ish min to make vit D
dark skin people need 40+ min to make vit D
What molecule is synthesized by the action of UVB light on cholesterol in the sebaceous glands of the skin?
7-dehydrocholesterol
7-dehydrocholesterol is synthesized by the action of UVB light on cholesterol in the sebaceous glands of the skin. Most of it is isomerized within 2-3 days into vit _____ also known as cholecalciferol
D3
note: D3 is hydrophobic bc its derived from a lipid molecule
Cholecalciferol diffuses from the skin into the capillaries and is transported via _________________ to peripheral tissues (liver)
vit D binding protein (DBP)
What are the 2 types of dietary vit D?
ergocalciferol/ D2 and cholecalciferol/D3
Which vit D is better for you because its plant based?
cholecalciferol/D3
50-80% of vit D consumed is incorporated into ___________ and is absorbed in the ____________
micelles, small intestine
Where is vit D absorption most rapid?
duodenum
Where is the majority of vit D absorbed (think specifics)?
distal ileum
Dietary vit D is transported via ________________ via the lymphatic system to the blood stream to the liver
chylomicrons
What are the food sources of vit D?
major forms:
-fatty fish (salmon, herring, mackerel)
-fish liver oils
-liver from animals
less major:
-fortified milk
-fortified margarines
-fortified cereal
-mushrooms
What foods are good for vit D3?
-fatty fish (salmon, herring, mackerel)
-fish liver oils
-liver from animals
What food is good for vit D2?
mushrooms
Cholecalciferol reaches the liver via ______________ (diet) or __________ (sun)
chylomicron remnants, DBP
Vit D2 gets converted to what when it reaches the liver?
vit D3
Vit D is activated by what organs?
liver and kidneys
Vit D3 is activated in the liver with 25 hydroxylase to make 25-OH-D3 also known as….
calcidiol
25 hydroxylase adds 1 OH to C25, so now calcidiol has 2 OHs
Vit D3 is activated in the kidneys with alpha 1 hydroxylase to make 1,25- (OH)2 D3 also known as…..
calcitriol (has 3 OHs)
What is the other name for 25 OH D3 and 25 hydroxycholecalciferol?
calcidiol
Where is calcidiol stored?
in adipose tissue (very little in the liver)
note: the storage form is created in the liver but most is stored in fat
What is the storage form of vit D3?
calcidiol
What is the active form of vit D3?
calcitriol
What is the other name for 1, 25- (OH)2 D3 and 1,25 dihydroxycholecalciferol?
calcitriol
Which hormone activates vit D when calcium is inadequate?
parathyroid hormone (PTH)
Excretion of vit D is mainly via….
bile
Can you get toxic effects from vit D naturally or through supplements?
no for both UNLESS you have kidney or liver issues
its not toxic bc vit D is inactive until it reaches liver or kidney
if theres liver or kidney issues then vit D cannot be activated and this will cause vit D deficiency which will make bones weak and this is called bone denomination bc of the fragility
vit D3 is also the precursor for prohormone so the other exception is that itll only be toxic if you take or consume excessive amounts of calcium or magnesium
One of the functions of vit D is to regulate blood calcium and phosphate levels. What are the 3 tissues involved?
bone, intestine, and kidney
One of the functions of vit D is to regulate blood calcium and phosphate levels. What are the 3 hormones involved?
1) parathyroid hormone (PTH)
2) calcitriol
3) calcitonin
blood calcium contributes to what?
blood clotting
Which hormone regulates calcium reabsorption and bone denomination?
parathyroid hormone (PTH)
Which hormone increases calcium and phosphate absorption and regulates bone denomination?
calcitriol
If you take vit D supplements, when is the best time to take it?
after eating, especially after eating foods rich in calcium and magnesium
tofu and eggs are rich in calcium
dark grean leaf veggies are rich in magnesium
Blood calcium levels drop during exercise. Is this an acute or chronic response?
acute
______________ creates a supersaturated calcium and phosphate solution. This causes calcium and phosphate to deposit in the bones and strengthen bones
Calcitriol
What disease is caused by low vit D in kids?
rickets (soft bones)
What disease is caused by low vit D in adults?
osteomalacia (soft bones, decreased bone density)
______________ can influence the differentiation and function of some cells by interacting with cell membrane receptors and nuclear vit D receptor proteins
Calcitriol
Adequate vit _____ status is linked to a reduction in breast, colon, and prostate cancer development
D
_______________ is a steroid hormone. So far, more than 50 genes are known to be regulated by it
Calcitriol
Which vitamin deficiency is most common?
vit D
What are the 6 risk factors for vit D deficiency?
1) inactive
2) slender (usually have smaller bones= less room for calcium and magnesium)
3) menopause
4) smoking
5) kidney/liver dysfunctions
6) fat free diet
Infants are born with enough vit D to last 4-6 months. After supplements are recommended for what benefits with baby?
increase brain function and calmness
Is breast milk a good source of vit D?
no
What is the tell-tale sign of rickets?
bowed legs
Only the active form of vit D can be toxic. The active form is calcitriol. What are the toxic effects here?
hypercalcemia (increased calcium in blood) and hypercalciuria (increased calcium in urine)
-kidney stones
-vomiting
-bone and muscle pain
-brain damage
-heart damage, irregular heart beat
-calcinosis (calcium deposit in soft tissues)
What is calcinosis?
calcium deposit in soft tissues (result of too much calcitriol)
Active forms of which vitamins in large amounts are lethal?
vit A and D
What is vit D resistance?
-lack of vit D synthesis in the kidneys or inability of vit D to bind to its nuclear receptors
-tx is to give a large dose of vit D but this will not help with the nuclear receptor problem
Which vit is the most important water soluble vit?
vit C
Vit ______ has 8 vitamers: 4 tocopherols (saturated side chains) and 4 tocotrienols (unsaturated side chains with double bonds)
E
The amount of vit E absorbed is dependent on…..
-fat intake/absorption
-bile and pancreatic enzyme activity
Which vitamer of vitamin E has the highest activity?
test q
alpha tocopherol
What is the most important fat soluble antioxidant?
test q
alpha tocopherol (a vitamer of vit E)
Which vitamin is a redox agent, meaning it can donate electrons to an oxidizing agent?
vit E
Which vitamin protects cells from attack of free radicals, prevents the alteration of the cell’s DNA and risk for cancer development, protects PUFAs within the cell membrane and plasma lipoproteins?
vit E
Vit E is incorporated into ________________ to the liver, then incorporated into ___________________
chylomicrons, lipoproteins
Which vitamin is found in cell membranes and all of the plasma lipoproteins?
test q
vit E
Where is vit E stored?
test q
adipose tissue, liver, and muscle
***mostly stored in adipose
Which vitamin neutralizes free radicals to make phospholipid bilayer more stable?
vit E
Glutathione (GSH) is made up of what AAs?
gly-cys-glu
Which enzyme is this?
-selenium containing enzyme
-helps breakdown peroxided (bad/rancid) FAs (that tends to form free radicals)
-lessens the burden of vit E
glutathione peroxidase
Which enzymes are this?
-reacts with hydrogen peroxide and single oxygen (free radicals)
-reduces free radical activity
superoxide dismutase (SOD) and catalase
Free radicals production is normal as a result of cell metabolism and immune function. Destructive to cells, sets off a chain reaction leading to lipid peroxidation. More vit E is found in the ____________ to protect them against oxidation and subsequent injury
lungs
What causes significant oxidative damage?
smoking
T/F: the combination of various antioxidants is more effective
true, megadose of one antioxidant may interfere with the action of another, so diversifying them and combining is good
What are the food sources of vit E?
-plant oils
-wheat germ (most cereals)
-peanuts
-maragine
-nuts and seeds
***actual amount of vit E conc. is dependent on harvesting, processing, storage, and cooking
What is the most concentrated source of vit E?
wheat germ (most cereals)
What is the healthiest option to increase vit E intake?
nuts and seeds
What are the signs and symptoms of vit E deficiency?
test q
-hemolytic anemia (RBC hemolysis)
-peripheral neuropathy
Is vit E deficiency common?
no its rare
Who is at risk for vit E deficiency?
premature infants and people with fat malabsorption
toxicity of vit ___= deficiency of vit _____
E, K
toxicity of vit E inhibits vit K metabolism and anticoagulants (pt would bleed out)
Koagulation is a mnemonic for
vit K is responsible for coagulation
What are the 3 types of vit K?
-phylloquinone (K1, from plants)
-menaquinones (K2, from bacteria)
-menadione (K3, synthetic form)
Where is phylloquinone (K1) found/ derived from?
derived from plants, found in dark green leafy veggies (bc they have lots of photosynthesis)
What is menaquinones (K2) synthesized from?
bacteria, so found in natto, cheese, miso, fermented foods
What is the synthetic form of vit K?
menadione (K3)
What percentage of dietary vitamin K is absorbed?
40-80%
Is vit K1 actively or passively absorbed?
actively absorbed into mucosal cells
What is required for vit K1 to be absorbed?
bile and pancreatic enzymes
Where is vit K1 stored?
liver
Vit K1 can easily be excreted so its only stored for _____ days
2-3
(excretion is primarily via the bile)
What are the 2 coagulation pathways?
1) extrinsic pathway
-tissue injury causes initiation of the clotting cascade by releasing certain blood proteins
-vitamin K acts at one of the steps in this pathway
2) intrinsic pathway
-blood vessel damage causes initiation of the clotting process
-vitamin K acts at 2 of the steps in this pathway
Vit K is required for the activation of what blood clotting factors?
test q
2, 7, 9, and 10
T/F: vit K activates clotting factors, it does not make clotting factors
true
Which vitamin is required for gamma-carboxylation of the glutamyl residues?
vit K
______________ inhibits the gamma carboxylation of glutamate
Warfarin
Prothrombin is synthesized by what vitamin?
vit K
Warfarin inhibits what cycle?
vit K cycle
What is warfarin?
blood thinner, prevents clotting
too much can cause internal bleeding
What are the vitamin K dependent proteins in skeletal tissues?
GLA protein (osteocalcin) and matrix GLA protein
In the mid 70s, severe cases of bone malformation were reported in newborns of women who had ___________ therapy during their pregnancy
warfarin
Low intake of vit K is associated with an increased risk of….
test q
hip fractures
Adequate amounts of vitamins __________________ are essential to prevent hip fractures. Synthesis of osteocalcin and matrix GLA protein is stimulated by 1, 25 (OH)2 D3 and retinoic acid.
A, D, and K
Which vitamin increases bone density?
vit D
Which vitamins are needed for strong bones?
A, D, and K
People taking _____________ will have decreased vit K reactivation, decreased blood clotting process, and monitor vitamin K intake
anticoagulants
People taking ______________ will destroy their intestinal bacteria, inhibit vit K synthesis and absorption, and there is a potential for excessive bleeding
antibiotics
Who is at risk for vit K deficiency?
new born babies (intestinal bacteria hasn’t been colonized yet) and fat malabsorption
What are the food sources for vit K?
-liver
-green leafy veggies like spinach
-broccoli
-peas
-green beans
T/F: vit K is resistant to cooking losses
true
Is vit K stored in the body?
yes but limited
Is breast milk a good source of vit K?
no, so babies are injected with vit K
T/F: vit K1/2 is toxic
false, very unlikely bc its easily excreted
Which vitamin removes CO2?
thiamine/B1
Thiamine is absorbed from the proximal SI by ___________ transport (low doses) and ___________ transport (high doses)
active, passive
What transport mechanism is inhibited in alcoholics and makes them have thiamine deficiency?
active transport
90% of thiamine is carried to the liver as….
thiamine pyrophosphate (TPP, which is a coenzyme)
Thiamine is stored in low amounts in what tissues?
-muscle
-heart
-brain
-liver
-kidney
Which vitamin is destroyed by alkaline environment and heat?
thiamine
How many ATPs are made per glucose when theres no thiamine?
2 ATP
How many ATPs are made per glucose when there is thiamine?
36-38 ATP
Is thiamine pyrophosphate (TPP) a coenzyme or cosubstrate?
coenzyme
Thiamine pyrophosphate (TPP) is necessary for several important steps in CHO and AA metabolism during decarboxylation. What 4 enzymes require thiamine?
1) pyruvate dehydrogenase (PDH)
2) alpha KG dehydrogenase
3) branch chain ketoacid dehydrogenase
4) transketolase (cytosolic enzyme in the hexose monophosphate shunt)
If someone is deficient in branch chain ketoacid dehydrogenase, then they have what disease?
maple syrup urine disease
BCAAs are important for what organs?
brain and heart
What are the food sources of thiamine?
test q
-whole grains (wheat germ, cereals)
-pork
-nuts
-yeast
Thiamine is found in a wide variety of foods at _______ concentrations. Yeast, whole grain, and pork are thiamines most highly concentrated sources but removal of the outer layer of grain in the refining process significantly lowers the thiamine content
low
What is the most common cause of thiamine deficiency?
alcohol abuse
What enzyme destroys thiamine and causes thiamine deficiency? Its found in raw fish, shellfish, cabbage, and brassicas
thiaminase
What is the phytochemical called that binds thiamine and causes thiamine deficiency? It is found in teas, coffee, and betel nuts
tannins
Ruminants is bacterial contamination of rumen (seen in cattle and sheep, mad cow disease) and causes _____________ deficiency
Thiamine
Eyelid swelling indicates issues of what organ?
kidney
What is wet beri-beri?
-blood pools in the legs and causes inflammation and fluid retention
-SOB + cardiovascular failure
-due to thiamine deficiency
What is dry beri-beri?
-peripheral nerves are damaged due to thiamine deficiency and causes numbness in hands and feet
-peripheral neuropathy
-if left untreated then it will lead to severe muscle weakness, difficulty walking, and even paralysis
What is Wernicke’s encephalopathy (also known as Wernicke- Korsakoff syndrome)?
-brain energy levels decrease and leads to speech problem due to thiamine deficiency
-dementia
-ataxia
-memory loss
-neuropathy
-the mammillary bodies are atrophic and discolored brown
-common in alcoholics
-if left untreated then it will result in irreversible brain damage and brain bleeds which is life threatening
-capillary proliferation, gliosis, neuronal loss and hemorrhage
What is the 3rd most common cause of dementia?
alcohol abuse
Marginal deficiency occurs when iron stores are depleted, but hemoglobin concentrations remain normal. This is common with what vitamin deficiency?
thiamine
1000x nutritional needs of what vitamin has been found to suppress the respiratory center causing death?
thiamine
What are the coenzyme forms of riboflavin/B2?
FAD, FADH2, FMN, and FMNH2
these are all the coenzyme form and they’re prosthetic groups, located in ETC inner membrane
Riboflavin/B2 participates in what reactions?
redox reactions
Urine will have a bright yellow color after consuming foods with what vitamin?
riboflavin/B2
Which vitamin is fluorescent and sensitive to UV radiation (easily destroyed)?
boards q
riboflavin/B2
FMN and FAD absorb only after ____________ cleavage of free riboflavin from its _____________________
hydrolytic, flavoprotein complexes
(flavoprotein complexes is when FMN or FAD is bound to an enzyme)
Riboflavin/B2 is absorbed in the free form by ______________ diffusion within the proximal SI
facilitated
How is free form of riboflavin transported in the bloodstream?
bound to albumin (plasma protein)
Is riboflavin/B2 stored anywhere in the body?
NO
Riboflavin is essential for the metabolism of carbs, AAs, and lipids. Riboflavin transfers electrons in the ETC respiratory chain complex _____ and ________
1 (FMN), 2 (FAD)
Riboflavin activates 2 vitamins. What are they?
test q
vit B6 and B9 (folic acid)
What are the food sources of riboflavin/B2?
-milk and milk products (should be in paper or white containers to protect B2 bc light would penetrate glass and destroy B2)
-liver
-fortified dry cereals
-pork
-broccoli and spinach
-whole grains
-nuts
-soybeans
What is chelosis?
-dry scaling surface on lips, causes a fissure
-result of riboflavin/B2 deficiency
What is angular stomatitis/chelitis?
-cracks in the skin in the corner of the mouth
-result of riboflavin/B2 deficiency
What are some weird symptoms of riboflavin/B2 deficiency?
-purple swollen tongue
-photophobia
-tearing, burning, or itchy eyes
-loss of visual acuity
-migraine
-soreness of lips, mouth, or tongue
Large dose of which vitamin is sometimes used as a migraine treatment?
riboflavin/B2
Who is at risk for riboflavin/B2 deficiency?
-alcoholics
-severe malnutrition (cancer or chronically ill) patients
T/F: riboflavin/B2 has no known toxicities
true
What are the coenezymes and cosubstrates of niacin/B3?
NAD and NADPH
NAD is used in what reactions?
oxidation reactions
NADPH is used in what reactions?
reduction reactions
NADPH is required for what biosynthesis?
FA biosynthesis
Niacin is a generic term used for….
nicotinamide and nicotinic acid
What is the synthetic form of niacin/B3 called?
nicotinic acid
A small amount of which 2 vitamins can be synthesized from tryptophan?
boards q
vit D and B3
define redox
add or removal of protons
NAD and NADP are used in what reactions/pathways specifically?
-pyruvate dehydrogenase (PDH)
-glycolysis
-TCA cycle
-ETC
-FA oxidation
-alcohol oxidation to acetate
Niacin/B3 is present in all foods but especially….
animal products
Where is niacin/B3 absorbed?
stomach and SI
How is niacin/B3 transported in the blood?
uncomplexed
Is niacin/B3 stored anywhere in the body?
NO
What are the food sources for niacin/B3?
-any animal food like meat liver, milk, eggs, etc
-enriched cereals, nuts, and grains
How many g of protein are there for 1 mg of niacin?
60 grams of protein
In order to synthesize niacin from tryptophan, 60mg of tryptophan makes….
1 mg niacin
What disease is common with niacin deficiency? What is it called and what diet causes it?
pellagra disease
-high corn, low protein diet (both are low in tryptophan)
Who is at risk for niacin deficiency?
-pellagra patients
-hartnup disease
-malnutrition from alcoholics, cancer patients, homeless people, or pts with PKU
-people taking anti-TB drugs
What is Hartnup’s disease?
-tryptophan cannot be absorbed
-niacin deficiency
What are the 4 D’s of pellagra?
-diarrhea
-dementia
-dermatitis
-death (eventually)
Which disease is common in countries where corn is a major staple?
pellagra
What is the treatment for pellagra?
nicotinamide and animal fat
Niacin/nicotinic acid, NOT nicotinamide, is a treatment for what disease besides pellagra?
CVD
What are the benefits of niacin/nicotinic acid for pellagra and CVD patients?
-lowers LDLs, TGs, and cholesterol
-raises HDL
-will see an average 10-15% drop in serum cholesterol overtime when taking 3-6g of niacin per day (prescription dose, fast release form, slow release does not work)
What is the side effect of taking fast release niacin/nicotinic acid (prescription form)
-nicotinic acid toxicity called flushing
-causes redness in skin, will look flushed everywhere
-so its best to take niacin at night and take aspirin with it to help with this
-flushing will go away within a week of taking it
If a patient has pellagra or CVD then one of the treatments is niacin/nicotinic acid. But if this patient has __________ or ____________ then they CANNOT take fast release niacin bc it will spike their blood glucose and BP
diabetes, hypertension
What is the other name for CoA?
coenzyme A
Which vitamin is used in any reaction with CoA present?
pantothenate/B5
Citrate synthase is the first step in the TCA cycle. It attaches acetyl CoA to OAA to make citrate. What vitamin is required?
B5
Which vitamin is required for FAs to enter mitochondria and FA synthesis?
B5
What acids are activated by CoA?
-acetic acid
-malonic acid
-propionic acid
-methylmalonic acid
-succinic acid
Which acid activated by CoA is used in FA biosynthesis?
malonic acid
Which acid is a product of odd chain FA catabolism and is activated by CoA?
propionic acid
T/F: CoA is a coenzyme
false, its a prosthetic group
Vit B5 is absorbed by ___________ diffusion after being _____________ from the CoA and ACP
passive, hydrolyzed
How is vit B5 transported throughout the body and taken up by peripheral tissues?
RBCs
Vit B5 is converted to _______ within the cell which is essential in energy production from macronutrients (CHO, PRO, and fat)
CoA
Is vit B5 stored anywhere in the body?
no
What are the food sources of vit B5?
basically in every food
-meat
-mushrooms
-broccoli
-egg yolks
-skim milk
-sweet potatoes
Vit B5 deficiency is rare but if you do have a deficiency then what happens?
-fatigue
-impairments in lipid synthesis and energy production
Are there any toxicities for vit B5?
no
T/F: biotin is a prosthetic group
true
Which vitamin aids CO2 to organic acids like AoCoA, PropCoA, and pyruvate?
biotin/B7
What is the coenzyme form of biotin/B7?
biocytin
Biotin is the prosthetic group of what enzyme?
carboxylase
Biotin/B7 is primarily bound to protein and released by __________________ to yield biotin
proteolytic digestion
The proximal intestine absorbs free biotin/B7 by _____________ diffusion
facilitated
Which vitamin can be stored in the liver but is not easily mobilized when that person is deficient (aka storage is not very useful)?
biotin/B7
Biotin is a ____________ carrier covalently bound to carboxylase enzymes
carboxyl
What are the 4 carboxylase enzymes biotin/B7 can be covalently bound to?
1) pyruvate carboxylase
2) acetyl CoA carboxylase
3) propionyl CoA carboxylase
4) 3-methylcrotonyl CoA carboxylase
Which enzyme converts pyruvate to oxaloacetate (OAA) in gluconeogenesis?
pyruvate carboxylase
Which enzyme synthesizes malonyl CoA for FA biosynthesis?
acetyl CoA carboxylase
Which enzyme allows the use of odd chain FAs by converting propionate to succinate?
propionyl CoA carboxylase
Which enzyme catabolizes leucine?
3 methylcrotonyl CoA carboxylase
What are the food sources of biotin/B7?
most food has it, but the highest conc. is in plant based foods
-liver
-soybeans
-egg yolks
-cereals
-legumes
-nuts
Which food source is a great source of biotin/B7?
soybeans
Which 2 vitamins are produced by bacteria within the colon?
vit K and B7/biotin
Raw egg whites and other foods have a protein called _________ which may irreversibly bind to biotin and prevent B7 absorption
test q
avidin
What are the 2 main things that can happen if you have a biotin deficiency?
1) acidosis
2) peripheral neuropathy
What is metabolic acidosis in relation to biotin/B7 deficiency?
-increased urine and blood levels of acetate, propionate, and pyruvate
-organic aciduria
-grey mucus membranes
Peripheral neuropathy due to biotin/B7 deficiency can also occur with what other disorder?
GI disorders like IBD
What are the symptoms of peripheral neuropathy + other general symptoms due to vit B7/biotin deficiency?
-tingling of hands and feet
-muscle pain
-anorexia
-nausea
-alopecia (hair loss)
-scaly dermatitis
-hallucinations
-depression
What are the 4 risk factors for biotin deficiency?
1) genetic defects (inborn error of metabolism)
2) high consumption of raw egg whites (avidin)
3) TPN (total parenteral nutrition, food thru veins, bypasses GI) patients with short gut
4) antibiotic treatments (reduced gut bacteria)
T/F: carboxylase is an apoenzyme
true
Biotin needs _________________ to link it to its target carboxylase protein and _______________ to release it for recycling
holocarboxylase synthetase, biotinidase
Which enzyme does biotin attach to at the active site?
holocarboxylase synthetase
(if biotin doesn’t attach at this active site then its inactive
Which enzyme releases biotin from holocarboxylase synthetase active site when holocarboxylase synthetase is degraded?
biotinidase
What is single carboxylase deficiency?
-either holocarboxylase synthetase or biotinidase is deficient
-usually due to a mutation
-may respond poorly to diet therapy
note: being deficient in holocarboxylase synthetase is much worse
What is multiple carboxylase deficiency?
-both holocarboxylase synthetase and biotinidase are deficient
-defective holocarboxylase synthetase will show signs in neonatal stage
-defective biotinidase will show signs in juvenile stage (much later onset)
-whole biotin pathway is defective
-may respond to biotin megadoses
What is the most common supplement form of vit B6?
pyridoxine (PN)
What is the prescription form of vit B6?
pyridoxamine (PM)
Which vit B6 is used to treat diabetic nephropathy?
pyridoxamine (PM)
All 3 forms of vit B6 (pyridoxine/PN, pyridoxal/PL, and pyridoxamine/PM) are converted to the metabolically active coenzyme form ________________________
pyridoxal phosphate (PLP)
Which vitamin is dephosphorylated before absorption and is rephosphorylated in the intestinal mucosa?
vit B6
Vit B6 is absorbed by ____________ diffusion primarily in the jejunum and ileum
passive
Pyridoxine phosphate and pyridoxamine phosphate changes to pyridoxal phosphate in the ________ after metabolism by _____________________
liver, hepatic flavoenzymes
Pyridoxal phosphate bound to ___________ is the predominant form of B6 in the blood
albumin
T/F: pyridoxal phosphate must be dephosphorylated to pyridoxal to be taken up by a cell, but once in the cell it has to be phosphorylated again
true
Which part of the body has the largest conc. of vit B6?
muscle has 90% of the vit B6 in our body
Can vit B6 be stored?
no
What are the functions of pyridoxal phosphate?
-essential for transaminiation/aminotransferases to work
-essential for the conversion of tryptophan to niacin and for tryptophan to be converted to serotonin, or tyrosine to be converted to catecholamines like dop, Epi, and NE
-needed for the conversion of serine into glycine in heme synthesis
What are the food sources for vit B6?
most foods
-meat
-whole grains
-veggies
-nuts
-bananas
-avocado
-egg yolks
What are the symptoms of vit B6 deficiency?
-depression
-irritability
-insomnia
-confusion
-peripheral neuropathy
-glossitis
-stomatitis
-cheilosis
-sideroblastic anemia
advanced stages= convulsions and scaly dematitis
If someone is depressed, what diet should they try?
keto diet, vit B6 within meat may help
What deficiency symptoms are the same for vit B2 and B6?
-glossitis
-stomatitis
-cheilosis
What is sideroblastic anemia?
-not enough heme and RBCs
-Fe is available and is waiting for heme inside the RBCs
-result of vit B6 deficiency
What are the risk factors for vit B6 deficiency?
-alcohol abuse
-being elderly
-taking anti-TB drugs
Which vitamin has these toxicity responses?
-may cause abnormal gait and peripheral sensation
-may lead to irreversible nerve damage
vit B6 deficiency
What is the most common B vit deficiency in the US?
folic acid
What is the nature form of folic acid called?
pteroylglutamate (exists in 150 different forms)
What is the synthetic form of folic acid called?
pteroylmonoglutamate (has only 1 glutamate, so compared to the nature form it has a much higher bioavailability)
In 1998, FDA required ________ products to be fortified with folic acid
grain
Absorption of folic acid occurs by ______________, mainly in the jejunum, and by ________________
active transport, passive diffusion
What vitamins are absorbed by active transport?
-K1
-folate
-B12
-low dose thiamine
-C
all other vits are through passive diffision
What organ stores folate? How long does storage last?
liver, storage can last for 3-5 months but it is not easily accessible if the person becomes deficient
The reduced compound of folate is tetrahydrofolic acid (THF) and it functions metabolically as a….
single carbon carrier
What are the food sources of folic acid?
-green leafy veggies like spinach, asparagus, and broccoli
-fortified grain products
-eggs
-liver
-mushrooms
-orange juice
-lean beef
-dried beans
Which vitamin is a fuel for cancer since it it essential for the synthesis of DNA and RNA?
folate
Which vitamin is essential for red and white blood cell regeneration in the bone marrow and their maturation?
folate
Which vitamin recycles methionine and homocysteine?
folate
What vitamins are deficient in homocystemina?
B6, B9, and B12
Which vitamins are deficient when methionine is deficient?
B9 and B12
What are the risk factors for folate deficiency?
-pregnant women
-alcoholics and older adults
-people taking anticonvulsants and oral contraceptives
Deficiencies of B2, B6, B12, iron, and vit C can impair which vitamin?
folate
What 2 vitamins are needed to recycle THF? If THF is not recycled then it is trapped in one form
B6 and B12
Which vitamin deficiency can lead to posterior neural tube defects like spina bifida?
folate
Which vitamin deficiency causes a blockage in DNA synthesis and slows down the maturation of RBCs causing the production of abnormally large “macrocytic” RBCs with fragile membranes called megaloblastic anemia?
folate
What are the GI symptoms for folate deficiency?
-glossitis
-irritability
-constipation
-diarrhea
-anorexia
-headaches
Homocysteinemia is associated with an increased risk for ________________ disease and is prevalent among apparently healthy Americans
occlusive vascular
What is the independent risk factor for heart disease?
homocysteinemia
What is the most common birth defect in the US?
spina bifida
Which vitamin toxicity renders zinc as unavailable and decreases zinc absorption in the gut?
folate toxicity
Which vitamin toxicity masks a vit B12 deficiency?
folate toxicity
Vit B12 is a family of cobalamin compounds containing the porphyrin-like cobalt-centered corrin nucleus. Vit B12 functions in 2 coenzyme forms. What are they?
adenosylcobalamin and methylcobalamin
Which vit B12 is the active form?
methylcobalamin
Vit B12 is bound to protein in food and must be released from it by _______ digestion in the stomach. It combines with _____________ in the stomach and moves to the SI where it will be hydrolyzed. B12 binds to intrinsic factor, forming a B12-intrinsic factor complex. Most of B12 is absorbed by an active process, and intrinsic factor is essential for it.
test q
pepsin, R proteins
Where is B12 stored and how long does storage last?
large amounts are stored in the liver, storage lasts for 3-5 years (so a B12 deficiency wouldn’t be evident for a long time)
What are the food sources of vit B12?
animal products only
-liver and kidney
-milk
-eggs
-cheese and muscle meats
note:
-plant origin contains B12 only through contamination or bacterial synthesis
-bacteria synthesizes B12 BUT B12 from bacteria is not absorbed
Which vitamin is essential for the conversion of methylmalonyl CoA to succinyl-CoA (odd chain FA catabolism)?
vit B12
Which vitamin is critical for folate recycling?
methylcobalamin
Homocysteine is converted back to methionine. This is catalyzed by what 2 vitamins?
folate and B12
Which vitamin deficiency would cause these issues?
-impaired cell division in rapidly dividing BM and intestinal mucosal cells
-abnormally large RBCs (megalobastic anemia) + pernicious anemia
-peripheral neuropathy symptoms like numbness, tingling, burning of the feet, stiffness and weakness of the legs
vit B12
What is pernicious anemia? What are the characteristics?
-malabsorption of B12 bc of inadequate production and secretion of intrinsic factor
-atrophy of the gastric parietal cells (results from aging or gastric bypass surgery)
-deficiencies in intrinsic factor synthesis
-autoimmune incapacitations of intrinsic factor
-this makes it difficult for the body to absorb vit B12 and causes a deficiency
At what age do parietal cells start to atrophy?
50 ish y/o
What are the risk factors for vit B12 deficiency?
-aging
-lack of intrinsic factors
-very strict vegan diets for many years with no consumption of any animal product w/o taking a B12 supplement
-breastfed infants of vegan moms not taking a supplement
-young children or infants maintained on unfortified foods of plant origin
-crohn’s disease
Are there any toxicities for vit B12?
no
What is the other name for vit C?
ascorbic acid
What is the major water soluble antioxidant that is also a vitamin?
vit C
Vit C functions in redox reactions and is synthesized by plants and most animals (not humans) from the _________________ pathway
glucuronate
Which vitamin helps to regenerate vit E?
vit C
Which vit conc. decreases in times of stress when adrenal activity is high and urinary excretion increases?
vit C
Which vitamin promotes resistance to infection through its involvement with the immunologic activity of leukocytes, the production of interferons, the process of inflammatory reactions, and the integrity of the mucus membranes?
vit C
Which vitamin converts folate to tetrahydrofolic acid?
vit C
Which vit oxidizes phenylalanine to tyrosine?
vit C
Which vitamin converts tryptophan to the neurotransmitter serotonin?
vit C
Which vitamin hydrolyzes proline and lysine in the synthesis of collagen?
vit C
Which vitamin facilitates iron absorption from the gut by keeping it in the reduced form, which is more absorbable?
vit C
Vit C is transported in plasma in the ascorbic acid form and is taken up by cells via….
active transport
Which vitamin competes with glucose for GLUT transporters?
test q
vit C
(the glucose transporter based system is stimulated by insulin and inhibited by glucose)
Is vit C stored anywhere in the body?
no
Who should increase their vit C intake compared to the average person?
smokers and sailers
What are the toxicity responses for vit C?
chronic diarrhea and kidney stones
What are the food sources for vit C?
fresh fruits and veggies
-citrus fruits
-strawberries
-blueberries
-peppers
-kale
-kiwi
-broccoli
Which vitamin can easily be destroyed by oxidation and heat?
vit C
What is scurvy?
-poor bone development
-poor wound healing
-lots of bruises
-due to vit C deficiency
-manifests 45-80 days w/o vit C
-in this case, the bone matrix is composed primarily of collagen
Which of the following is true in terms of fat soluble vitamins?
A) people eating high fats are susceptible to fat soluble vitamin deficiencies
B) cholesterol and fat soluble vitamins are excreted in the urine
C) fat soluble vitamins are usually stored
D) doses of vitamins well above RDA are nontoxic medicines to treat diseases
C) fat soluble vitamins are usually stored
T/F: vit K is the least efficiently excreted of all the fat soluble vitamins
false
T/F: all lipid soluble vitamins are considered hormones
false
T/F: foods in general can produce vit D by exposure to UV light
false
T/F: antibiotic use can provoke vit D deficiency
false
It is critical for a surgeon to know the vit ____ status of a patient before operation
K
Which is not a correct match in terms of the function of vitamins with regard to exercise?
A) thiamine needs are related to the amount of fat intake
B) B2, B3, and B5 are heavily involved with energy metabolism
C) B6, B9, and B12 participate in RBC formation
A) thiamine needs are related to the amount of fat intake
T/F: milk is a good source of riboflavin
true
T/F: thiamine is found in high quantities in beef
false
T/F: physicians should investigate poor absorption of B12 in their elderly patients
true
T/F: niacin and cholecalciferol can be synthesized in our body
true
T/F: a niacin deficiency causes severe skin inflammation
true
T/F: nicotinic acid can lower serum cholesterol levels
true
T/F: B12 is present only in animal foods
true
T/F: biotin is critical in preventing the depletion of OAA in TCA cycle. Without biotin, TCA cycle could not run efficiently
true
T/F: intestinal synthesis of biotin and vit K by bacteria supplies at least part of our needs
true
Which of the following is important in conversion of pyridoxine phosphate to pyridoxal phosphate?
A) thiamine
B) niacin
C) riboflavin
D) folate
C) riboflavin
What vitamins are involved in the folate cycle?
-folate
-vit B6
-vit B12
