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vitamins
cmbm exam II
102
Chemistry
Graduate
12/11/2009

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Term
what is the study of nutrition?
Definition
the study of how food nourishes our bodies and influences our health
Term
what is the definition of wellness?
Definition
absence of disease, (physical, emotional, spiritual health)
Term
what are diseases where nutrition plays some role?
Definition
osteoporosis, osteoarthritis, some forms of CA
Term
what are diseases with a strong nutritional component?
Definition
type 2 diabetes, heart disease, HTN, obesity
Term
what are diseases caused by nutritional deficiencies or toxicities?
Definition
pellagra, scurvy, iron-deficiency anemia, other vitamin/mineral deficiencies, nutrient toxicities
Term
what percentage of the US population is overweight? why is this a growing problem?
Definition
65% obese children are being diagnosed with type 2 diabetes
Term
what are the "goals of healthy people 2010"
Definition
increase quality and years of healthy life
eliminate health disparities
Term
what are nutrients?
Definition
the chemicals in foods that are critical to human growth and function:
carbs, fats,oils,proteins,vitamins,minerals,water
Term
what are vitamins?
Definition
organic molecules that assist in regulating body processes, but do not supply energy. they can be fat or water soluble
Term
what are the fat soluble vitamins?
Definition
K,A,D,E -> can be stored in the body, (deficiencies in these can be harder, but if gall bladder is removed - possible)
Term
what are the 2 important D vitamins?
Definition
ergocalciferol, (D2) and cholecalciferol, (D3)
Term
where is ergocalciferol, (D2) found? what can it be converted to?
Definition
ergocalciferol, (D2) is exclusively found in plant foods, it can be converted to calcidiol in the liver
Term
where is cholecalciferol, (D3) found? what can it be converted to?
Definition
cholecalciferol, (D3) is exclusively found in plant foods, it can be converted to calcidiol in the liver
Term
what is 7-dehydrocholesterol? what population is this becoming more of a
Definition
vitamin D3, a provitamin in the skin, which gets converted to cholecalciferol in the sunlight.
Term
what population is 7-dehydrocholesterol deficiency becoming more of a problem with? what has it been linked with?
Definition
the elderly, it has been linked with obesity, depression and osteoporosis.
Term
what can be a problem with sunblock?
Definition
sunblock is not particularly effective in preventing skin CA, and that it can cause vit D3, (7-dehydrocholesterol) deficiencies
Term
what angle of UVb light is needed to break the bonds of 7-dehydocholesterol -> cholecalciferol? what time of day is the sun at this angle? what else is a consideration?
Definition
120, 11am-1pm. also depends on season, location, sunscreen, skin type
Term
what is calcitriol? what is it converted from? where? what hormone is involved?
Definition
the active form of vitamin D, it is converted from calcidiol in the kidneys under the influence of parathyroid hormone
Term
can calcitriol be prescribed as an rx? what is its function in the body?
Definition
yes. it regulates blood Ca++ levels, thought to inhibit cell proliferation, (anti-CA), and enhance cell differentiation
Term
why is prescribing calcium to pts with osteoporosis on its own ineffective?
Definition
it needs regulation by vit D
Term
where does calcitriol bind?
Definition
cell nucleus, increases cell transcription
Term
what needs to be closely monitored in dialysis pts?
Definition
Ca levels
Term
where is 95% of Ca stored?
Definition
bones, teeth
Term
what happens when Ca levels drop?
Definition
the parathyroid glands releases PTH, which stimulates the activity of osteoclasts, releasing Ca into the blood. PTH also stimulates the kidneys to activate vit D and decrease Ca excretion
Term
what does calcitriol do to PTH?
Definition
calcitriol enhances the activity of PTH on bone cells and stimulates intestinal cells to synthesize Ca transport proteins -> enhancing Ca absorption from food
Term
what is one effect of being on corticosteroids for a prolonged amount of time? how?
Definition
osteoporosis, they counteract the activity of hormones that control osteoblasts -> loose Ca
Term
what is the optimal vit D blood level?
mildly deficient?
severely deficient?
possible toxicity?
Definition
optimal = 32-100 ng/mL
mildly deficient = 15-31
severely deficient = <14
possible toxicity = >100
Term
where is vit D stored?
Definition
liver, adipose
Term
what is AI recommendation for vit D? what is assumed in this recommendation?
Definition
5 mcg/day. the assumption is no vit D is produced in the skin
Term
what foods have vit D?
Definition
fortified foods, fish (oil), sometimes egg yolk
Term
how does vit D deficiency manifest itself?
Definition
rickets in children, osteomalacia in adults, (dialysis, CA, glandular disease pts)
Term
what is osteomalacia?
Definition
osteomalacia is the softening of the bones due to defective bone mineralization
Term
is osteoporosis associated with Vit D deficiency? can supplementation increase bone density of people without of deficiency?
Definition
yes and yes
Term
can toxicity from Vit D occur from sun exposure?
Definition
no
Term
what does toxicity from Vit D cause?
Definition
hypercalcemia, overly high levels of intestinal Ca transporter expression, bone loss from too much osteoclast expression
Term
what group of compounds is vit K associated with? what sources do they come from? which is most active?
Definition
quinones, phylloquinones are the most active, they come from plant sources, menaquinones are from animal sources and human intestinal synthesis, (accomplished by e coli)
Term
what is the function of vit K? are there drugs that inhibit it?
Definition
is is necessary for 7 of the proteins necessary for clotting. coumadin and warfarin both inhibit it, (plavix doesn't)
Term
how does vit K affect bone formation?
Definition
vitamin K facilitates carboxylation of osteocalcin, a bone protein necessary for mineralization/maturation, this carboxylation enhances its Ca binding properties
Term
how can a vitamin K deficiency cause Ca stones? does decreasing dairy help with Ca stones?
Definition
lack of Vit D decreases osteocalcin's Ca binding properties, and it's "sticky state" causes Ca buildup to form stones. decreasing dairy doesn't help with Ca stones, in fact it makes the situation worse, b/c Ca deficiency is the cause of the stones
Term
what are sources of vit K?
Definition
intestinal bacteria, green leafy vegetables
Term
what is the RDA for males, women?
Definition
80 mcg males, 65 mcg females, (lower b/c they rely on endogenous source)
Term
what does vit K do for cosmetic concerns?
Definition
it can decrease melasma
Term
what happens with vit K deficiency? what can cause it?
Definition
it is rare
usually associated with prolonged use of antibiotics or people with their gall bladder removed, (food isn't properly broken down, essential nutrients are not absorbed), megadosing of other fat-soluble vitamins like A and E, (all use the same transport).
Term
what type of vitamin is easier to have a deficiency in? why?
Definition
water soluble vitamins are eliminated by the kidneys and cannot be stored in our bodies
Term
what are the water soluble vitamins?
Definition
C and B
Term
what is vitamin B1?
Definition
thiamin
Term
what what is the structure of thiamin, (vit B1) like?
Definition
thio- means sulfur. it has a sulfur containing ring attached to the central carbon atom, and heat easily breaks this attachment
Term
most of the B vitamins are heat labile, what does this mean?
Definition
heat easily destroys them
Term
what is the function of vitamin B1, thiamin?
Definition
it is part of thiamin pyrophosphate, (TPP), which is a cofactor in the decarboxylation of pyruvate in the pyruvate->acetyl-CoA rxn as well as a cofactor in the very similar alphaketoglutarate dehydrogenase rxn of the TCA cycle, as well as the non-oxidative portion of the PPP, (ribose, NADPH produced). IMPORTANT FOR BETA OXIDATION, NERVOUS SYSTEM CONSTRUCTION
Term
what are good sources of vitamin B1? what are RDAs for males/females?
Definition
pork, and wheat germ, (little in most animal foods). RDA for males: 1.2 mg/day, females:1.1
Term
what is vitamin B1 deficiency called?
Definition
beriberi: muscle weakness, appetite loss, nerve degeneration, (myelin sheath is mostly omega 3 FAs). shortness of breath, heart failure, (prefer FAs as fuel to glucose)
Term
what does beta oxidation require?
Definition
vitamin B1
Term
what is "wet beriberi"?
Definition
edema, fluid retention, enhanced protein excretion, due to albumin loss -> decreased contractility of the heart, fluids stay in tissues
Term
what is "dry beriberi"?
Definition
muscle weakness, not enough ATP supplied, (speech difficulties, vomiting, strange eye movements)
Term
how does beriberi affect the brain?
Definition
the brain and nervous system rely on TPP for glucose metabolism which makes up its primary energy source.
Term
why is beriberi associated with alcoholism?
Definition
alcohol displaces other foods and interferes with the adsorption of thiamin, (inhibits anti-diuretic hormone, urinating a lot, water soluble vitamins included)
Term
what is riboflavin? what reducing equivalent is it associated with? what action does it perform?
Definition
vitamin B2, (vitamin G). flavin adenine dinucleotide = FAD, which acts as a hydrogen & electron acceptor. FADH2 delievers electrons to the electron transport chain -> ATP production
Term
what are B vitamins involved with?
Definition
fat, carb, and protein metabolism, (essentially all vital functions of body)
Term
what is riboflavin involved with?
Definition
deamination of some amino acids, TCA cycle, beta oxidation
Term
what environmental condition causes riboflavin requirements to be higher?
Definition
colder weather
Term
what physiologic situation would lead to a higher need for riboflavin, (vit B2)? why?
Definition
overweight pt dieting, due to a higher rate of beta oxidation
Term
what are symptoms of riboflavin deficiency?
Definition
angular stomatitis, (irritation/cracking at corners of the mouth), glossitis, (irritation of the tongue)
Term
why is (unfortified) milk in a clear container not a good source of riboflavin?
Definition
UV light degrades vit B2
Term
what is niacin? what can it be used for?
Definition
vitamin B3, (nicotinic acid/nicotinamide), it can help lower bad cholesterol, (LDL, VLDL), and increase levels of HDL. it can be more effective than some more expen$ive rxs, (those that block HMG CoA inhibitors or are statins)
Term
can niacin be endogenously produced? what do compounds containing it do?
Definition
vit B3, niacin, can be endogenously produced. NAD accepts H+ and electrons to form NADH which alternately carries electrons to the electron transport chain or powers the pyruvate -> lactate conversion.
Term
what are good sources of niacin? what amino acid can it be derived from?
Definition
meat, poultry, fish grains. 60 mg tryptophan = 1 mg niacin/NE
Term
what is the niacin/vit B3/NE RDA for males? females?
Definition
males: 16 mg NE
females: 14 mg NE
Term
what are the 3 "Ds" of niacin deficiency?
Definition
dementia, diarrhea, dermatitis
Term
what is pellegra?
Definition
rough/red skin at areas of sun exposure related to niacin deficiency
Term
what 3 cofactors are needed for the conversion of tryptophan to niacin?
Definition
riboflavin, (vit B2), B6, and iron
Term
what is the recommended dose for medicinal niacin? what is the one common adverse effect?
Definition
3000mg/day. hot flashes
Term
what is pantothenic acid? what compound is it associated with?
Definition
vitamin B5. it is a component of CoA, (acyl carrier)
Term
what processes is pantothenic acid involved with?
Definition
both energy yielding, (catabolic), and biosynthetic - component of elongase, (increases FA chain length), (anabolic), pathways
Term
are vitamin B5 deficiencies common? where is it abundant in the body?
Definition
no. it is abundant in the liver
Term
what is biotin? can it be endogenously produced?
Definition
vit B7, sulfur containing, (biocytin amount in food has not been accurately evaluated - B7 food form). there is some synthesis of biotion by bacteria in the large intestine, therefore it can be affected by antibiotics
Term
what does biotin do?
Definition
biotin, (vit B7), catalyzes carboxylation rxns:
pyruvate->oxaloacetate, (via pyruvate carboxylase)
3C FAs -> TCA ,(propionyl CoA -> succinyl-CoA via propionyl-CoA carboxylase)
elongation of FA chains in FA synthesis
Term
if infants have a build up of LCFAs, is this evidence of a biotin deficiency?
Definition
no, biotin deficiencies have not been adequately studied. this would be due to a lack of propionyl-CoA carboxylase
Term
how is biotin deficiency related to diabetes?
Definition
pts are creating propionyl-CoA, but instead of it being made in to succinyl-CoA and used in the TCA or elongated,(both via biotin), it gets made into glucose in the liver
Term
what symptoms have been noted among test volunteers who went off biotin?
Definition
nausea, loss of appetite, numbness, muscle pains, rashes, depression, anemia and high cholesterol
Term
is biotin deficiency related to hair loss?
Definition
yes, including male baldness
Term
can a rare form of infant SK respond to biotin treatment?
Definition
yes, but the reason is unknown
Term
how can biotin deficiency occur in the elderly? how is this treated?
Definition
the enzymes in the intestine that extract biotin get "worn out" and unable to process the nutrient. larger doses of vit B7 can bypass this and go -> bloodstream
Term
what are food sources of biotin? what is its AI?
Definition
cauliflower, peanuts, liver. egg yolks do but egg whites have a protien that binds biotin, therefore biotin deficiencies can occur from over consumption of raw eggs. AI is 30 mg/day
Term
what are pyridoxal, pyridoxine, and pyridoxamine?
Definition
PL, PN, PM are all forms of vit B6, and the phosphorylated forms, PLP,PNP,and PMP also exist in fat and protein metabolism. (however, if in food, the Pi is removed in digestion)
Term
what is the function of vit B6 related to proteins?
Definition
pyridoxal, pyridoxine, and pyridoxamine are all involved in transamination of the 11 non-essential AAs, (however w/out B6, all AAs are "essential")
Term
non-essential AAs are often used for ________and essential AAs are often used for _________
Definition
non-essential AAs are often used for catabolic processes and essential AAs are often used for anabolic processes
Term
which vitamins are necessary for RBC and WBC formation?
Definition
vit B6 + vit B12 (important for anemia tx)
Term
other than synthesis, how can vit B6 be related to anemia?
Definition
inadequate B6 disturbs the binding process of O2 to Hb, resulting in microcytic hypochromic anemia, (smaller cells w/less Hb)
Term
what vitamins influence, (reduce), homocysteine levels? why is this important?
Definition
vit B6,9, 12. homocysteine is a substrate in the SAM cycle to produce methionine, cysteine, (+ precursor molecules for DNA synth), and if it builds up in the arteries it stimulates the immune system which attacks it, causing inflammation/plaque build-up
Term
what are sources of vit B6, (pyridoxal, pyridoxine, and pyridoxamine)?
Definition
fortified cereals, bananas, fish, meat, poultry.
Term
how does alcohol affect levels of vit B6? what consideration does a high protein diet require in terms of vit B6?
Definition
alchol decreases absorption, along with synthesis of PLP. high protein diets require more vit B6, (pyridoxal, pyridoxine, and pyridoxamine)
Term
what is folate?
Definition
vit B9. it has 3 parts:
pteridine
para-aminobenzoic acid (PABA)
when one glutamate is removed in small intestine = folic acid
Term
what happens with a PABA deficiency?
Definition
fast-proliferating hair and skin cells degenerate. seen in anti-CA rxs, which stop folic acid from being converted to its active form.
Term
what is the function of folate, vit B9?
Definition
it is converted in the body to tetrahydrofolic acid, (THFA), which has 5 forms that accept/donate 1 C units during DNA syth, AA metabolism, cell division, and RBC maturation, (esp important in fast proliferating cells, hair, skin RBC). also works with vit B6,12 to reduce homocystiene
Term
where is folate found? is it heat/light labile?
Definition
yes it is heat/light labile. fortified cereals, dark leafy vegetables. prescence of food decreases absorption, so DRI is expressed as DFE, which is 400 mcg per day, (male&female, but x2 for pregnant women)
Term
what are deficien
Definition
Term
what are causes of vit 9/folate deficiency?
Definition
inadequate consumption of right foods
inadequate absorption due to GI tract problems
increased requirement, (pregnancy, can cause spina bifida)
impaired B9 utilization paired with B6 deficiency
altered fotate metabolism due to alcohol/drug abuse
excessive excretion due to diarrhea
Term
how can deficiency in either vit B9 or B12 affect RBCs?
Definition
lack of either can impair DNA synth, creating large, misshapen cells called megaloblasts. megaloblasts mature into macrocytes, which have shorter life spans and their presence will decrease normal RBC levels -> lowering total O2 carrying capacity
Term
how does folate, B9 depend on B12? what other disease can this appear as?
Definition
folate needs b12 to convert to THFA to its (active) methylene form. therefore, B12 deficiency can cause a B9 deficiency. deficiency of both can appear as bell's palsy
Term
how does vit B12 affect the SAM cycle?
Definition
it converts homocysteine to methionine, reducing homocysteine levels
Term
what does vit B12 do in terms of FAs?
Definition
it maintains the mylein sheath as well as prepares FAs to enter the TCA. remember for pts on diuretics, vegetarian diet.
Term
what rxs can cause deficiencies in vit B9+12?
Definition
anti-seizure drugs
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