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PCL469 > Vitamins > Flashcards

Vitamins Flashcards

1
Q

DRI

A

Daily Reference Intakes

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2
Q

EAR

A

Estimated Average Requirement: daily nutrient intake estimated to meet req of 50% of healthy individuals in specific group

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3
Q

RDA/RDI

A

Recommended Daily Allowance/ intake:
Average Daily nutrient intake level estimated to meet the req of nearly all healthy individuals in a specific life stage or gender group = EAR*2 standard deviations

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4
Q

AI

A

Adequate intake: used when RDA is unknown

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5
Q

UL

A

Upper limit: in supplements: to pose no risks

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6
Q

Macronutrients

A

Proteins, Carbs, Fats. 56:130:14 g/d (RD/AI adults)

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7
Q

Micronutrients

A

Vitamins, minerals, trace elements
Individual RDA/AI

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8
Q

Vitamins def

A

Organic chem supplied exogenously to reach adequate functional amounts

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9
Q

Only non-exogenous vitamin

A

vitamin D

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10
Q

Fat-soluble vitamins

A

ADEK

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11
Q

Water soluble vitamins

A

C and B

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12
Q

Primary vs secondary vitamin deficiency

A

Primary: inadequate intake
Secondary: absorption and/or drug-nutrient interaction issues, increased requirements

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13
Q

Absorption of Fat-soluble vitamins + examples

A

bile salts enhance or are required, ex beta-carotene, vit A precursor
Reduced absorption with increased intake like Vit E

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14
Q

Transport of fat-soluble vitamins

A

vit E transported in blood by plasma beta-lipoproteins
Vit A and beta-carotene transported from intestine in chylomicrons via lymph
Vit A released into the plasma as retinol bound to RBP (ret binding protein)

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15
Q

Storage of fat-soluble vitamins

A

A and E mainly in liver, some in muscle, kidney, adipose tissue and lung
E mobilized slowly from adipocytes
vit K storage limited, depleted in 10-20 days

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16
Q

Vitamin A conversion pathway

A

beta-carotene –> retinal –> retinol (vit A)

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17
Q

beta-carotene vs retinols and retinals

A

Beta-carotene from plants, less easily absorbed than retinal and retinols
Retinols from animal products, like fish and dairy

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18
Q

RDA vitamin A

A

700 ug/d females
900 ug/d males
about 1 cup raw carrot

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19
Q

vitamin A functions

A
  1. cellular differentiation - immunity development
  2. visual pigments - opsin binds retinal = rhodopsin
  3. Regulation of gene expression via retinoic acid
    all-trans retinoic acid binds to RAR, RAR+RXR binds RARE
    RAR- retinoic acid receptor RXR = retinoid X receptor
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20
Q

Vitamin A deficiency

A
  • leading cause of blindness in developing nations = dietary deficiency
  • increase infectious diseases, resp, GI
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21
Q

Vit A: pharma uses

A
  • skin conditions, acne, fine lines, blemishes
  • acute promyelocytic leukemia (RAR mutations, impaired diff of promyelocytes (PCL302))
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22
Q

Vitamin A toxicity: reason, acute effects, long-term toxicity

A
  1. Results from excess supplementations
  2. Acute effects of 1 dose 200 000 mcg: blurred vision, vertigo, nausea
  3. Long-term toxicity: liver damage, birth defects, skin + joint damage
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23
Q

Vitamin E; 2 types, how many subtypes each has

A

Four tocopherols, and four tocotrienols (alpha, beta, gamma, delta), sat vs unsat side chain

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24
Q

Vit E with highest nutrient significance, where found

A

Alpha-tocopherol- greatest nutritional significance
plant source: veggie oils, wheat ger,

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25
Vitamin E: highest bio activity
d-alpha-tocopherol
26
RDA of Vit E
RDA 15 mg/d, alpha-tocopherol 100 ml canola oil, 15 tbsp wheat germ
27
Vitamin E functions
- antioxidant - prevents lipid oxidative damage - inhibits PKC, cell signalling - inhibits platelet aggregation - enhance vasodilation - Affects activity of immune + inflammatory cells
28
Prevalence of vitamin E deficiency
Rare in healthy adults
29
Reason for vit E deficiency
- chronic fat malabsorption or beta-lipoprotein deficiency - premature infants - limited storage, absorption
30
Symptoms of vit E deficiency
- Anemia - reduced erythrocyte survival - Progressive neurological disorder - impaired balance + neuropathy
31
Vit E: absorption, circulation, storage
1. 50% absorption 2. Circulates bound to beta-lipoprotein 3. Storage: liver, muscle and fat
32
Therapeutic use/prevention
Treatment of susceptible individuals - preventing CVD
33
Range of vit E toxicity
Limited, when >2000 mg alpha-tocopherol/day
34
Toxicity of vitamin E
- May exacerbate a vitamin K deficiency - Possiblity of impaired blood clotting - hemorrhage
35
Vitamin E downreagulates these drugs:
Anticoagulant therapy, antiplatelet drugs, vitamin K deficient individuals
36
These drugs downregulate vitamin E absorption :
cholestryamine colestipol isoniazid mineral oil phenobarbital phenytoin carbamazepine
37
Natural occurring vitamin K
plants: phylloquinone K1 bacteria: menaquinone-n K2
38
dietary sources of vitamin K
K1: green leafy veggies K2: egg yolk, fermented food, microbiota
39
RDA vitamin K
90 mcg, 1/2 cup cooked kale - 530 ug
40
Vitamin K epoxide cycle
Vit K --> Reduced vitamin K, Hydroquinone --> Vitamin K epoxide --> vit K
41
Enzyme quinone reductase
vitamin K --> reduced vit K, Hydroquinone
42
Carboxylase
HYdroquinone --> vit K epoxide also produces gamma -carboxylated proteins clotting factors matrix gla proteins MGP
43
what does matrix gla protein do?
inhibition of innapropriate calcification/mineralization when not in skeletal tissue, both MGP + K need carboxylation to properly work
44
Epoxide reductase
Vitamin K epoxide --> vitamin K, recycling step
45
Vit K epoxide enzymes inhibited by warfarin
Quinone reductase, Epoxide reductase, if want low clotting, anticoagulation
46
Calcification in bone vs prevention of calcification in arteries
in bone - vitamin K, but prevent calc. in arteries - MGP, still need preventing surplus of K
47
Vitamin K functions
Coagulation, calcium-binding of some proteins, bone mineralization, cellular growth and regulation
48
Vitamin K dependent clotting factors where, coenzyme for what, conversions?
Synthesized in the liver, coenzymes for the gamma-carboxylation of glutamin acid residues result in conversion to gamma-carboxyglutamic acid
49
Vit K storage, recycling
Limited storage 10-20 days reused by oxidation/red cycle
50
What produces Vit K deficiency
Malabsorption Administration of antagonist warfarin chronic use cephalosporin antibiotics
51
Vit K deficiency symptoms
Increased prothrombin time - bleeding, hemorrhagic disease of the newborn first evident in GI bleeding
52
Therapeutic uses of vit K
increase biosynthesis of liver clotting factors prevention of hemorrhagic disease of newborn antidote for anticoagulant toxicity
53
Vitamin D, how is it different
not a true vitamin - can be synthesized by body
54
Derivation of vit D
from cholesterol D2 from plants - ergocalciferol D3 from animals - cholecalciferol
55
Vitamin D regulation of gene transcription
calcitriol + VDR complex in nucleus Complex binds with RXR to form heterodimer binds to vitamin D responsive elements Change in gene transcription (bone related genes, 24 hydroxylase, p21, TGFbeta2 and others)
56
Vitamin D synthesis in body
7-dehydrocholesterol + UVB in skin converted to Cholecalciferol vit D in liver converted to Calcidiol 25-hydroxyvitamin D3 in kidney conv to Calcitriol 1,25 dihydroxyvitamin D ^^ active form - bone + small intestine
57
Vitamin D actions
- increase calcium absorption from gut - increase bone mineralization - regulation of immune function
58
When lack of UVB Toronto and Edmonton to make it D
Latitude 43.6 N - Toronto: Nov-Feb Latitude 53 N - Edmonton - Oct-March
59
Vitamin D insufficiency definition
Conservative <40 nmol/L lack of 25 (OH)-D, the calcidiol in the kidney- easier, higher to measure in blood No stimulation of PTH when < 80 nmol/L
60
Vitamin D deficiency in children
Rickets: Insufficiency or mutations in VDR
61
Vit D deficiency in adults
Osteomalactia: rare, decrease in bone mineral [], bone pain and soft bones
62
Toxicity of vitamin D from what
from chronic high dose supplementation higher potential with supplemented calcitriol
63
Reason for adverse effect of vit D
Adverse effects from elevated blood calcium levels
64
Symptoms of vit D toxicity
Fatigue, headache, diarrhea, hypercalcemia demineralization of bone and calcification of organs such as heart, kidneys, lungs, blood vessels and skin, growth arrest too low - low mineralization too much - remove mineralization as well
65
Vitamin D bioregulation when low Ca++
Low ca --> parathyroid gland--> increase PTD --> increase Ca++ reabsorption and PO4 excretion in kidneys Increase calcitriol from kidney--> Ca++ reabsorption from intestine PTH --> Higher CA++ PO4+ release from bone Result normal Ca++
66
What does PTH do?
Stimulate hydroxylases
67
Normal range calcium extracellular
2.2-2.7 mM
68
Hypocalcemia: symptoms
<2.05 mM Symptoms; related to increased neuromuscular irritability numbness, tingling in fingers, toes muscle cramps, tetany, convulsions irritability, impaired mental capacity Laryngospasm, bronchospasm, cardiac arrest
69
Hypocalcemia: causes
Hypoparathyroidism Vitamin D deficiency Vitamin D resistance
70
Hypercalcemia symptoms
>2.96 mM Symptoms: Decreased neuromuscular activity Lethargy, lack of concentration, sleepiness Headache, muscle weakness Vomiting, diarrhea, polyuria, nocturia
71
Hypercalcemia Causes
Hyperparathyroidism Malignancies Ectopic vitamin D production
72
Vitamin D therapy
Ergocalciferol vitamin D2 Calciferol Drisdol (ergocalciferol) 25 hydroxyvitamin D2 Calcitriol 1.25 dihydroxyvitamin D3
73
Considerations for therapy with vitamin D
Time to reach equilibrium Fat malabsorption, hepatobiliary disease or renal disease
74
Drug interactions with vitamin D
Anticonvulsants: inhibit hydroxylation in liver Glucocorticoids: inhibit actions of vitamin D at the VDR

PCL469 (6 decks)

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