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3 Path Unit > Vitamins I and II > Flashcards

Vitamins I and II Flashcards

1
Q

Which vitamins are fat soluble?

A

KADE

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2
Q

Name 3 vitamins that are made endogenously

A

D, K, niacin

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3
Q

T/F- fat soluble vitamins are more easily stored long term than water soluble?

A

true

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4
Q

What two things are important for absorption of fat soluble vitamins?

A

bile, pancreatic enzymes

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5
Q

List fat malabsorption syndromes.

A 
abetalipoproteinemia
celiac disease
cholestasis
inflammatory bowel disease
cystic fibrosis
gastric bypass surgery
Also: use of bile acids or mineral oil
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6
Q

T/F- vitamin A is a name given to a group of related compounds, some of which act as hormones

A

true (retinol, retinal, retinoic acid)

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7
Q

Name dietary sources of vit A

A

animal: liver, fish, eggs, milk

plant (carotenoids): 6-carotene, yellow/green vegetables

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8
Q

where is B-carotene converted to retinol?

A

intestine

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9
Q

Where are more than 90% of vitamin A reserves?

A

liver

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10
Q

Name 4 biological roles of vitamin A

A
  • vision
  • cell growth/differentiation (epithelial/keratin)
  • metabolic effects of retinoids (bind to nuclear hormone receptors)
  • Resistance to infection (mucocilliary/intestinal tract cell differentiation and retinoid immune effects)
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11
Q

Earliest manifestation of vitamin A deficiency?

A

reduced night vision

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12
Q

Five effects of chronic vitamin A deficiency?

A
  • xeropthalmia (dry eye)
  • xerosis conjuntivae
  • bitot spots (keratin deposits)
  • keratomalacia (drying/clouding of cornea)
  • blindness
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13
Q

Name 3 therapeutic uses of retinoids

A
  • severe acne
  • psoriasis
  • acute promyelocytic leukemia
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14
Q

T/F- retinoids aren’t teratogens

A

FAlse. They are! also restrictions on donating blood when taking these because of possibility of getting into a pregnant woman.

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15
Q

What is the most common fat-soluble vitamin poisoning in the united states?

A

Vit A

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16
Q

Symptoms of vitamin A poisoning?

A
  • desquamation
  • headache/dizziness/vomiting
  • pseudotumor cerebri
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17
Q

Chronic excessive vitamin A results in bone resorption and fractures. T/F

A

True

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18
Q

T/F- vit D only affects a limited number of organ systems

A

False, it affects nearly every organ system

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19
Q

What receptor does it D act on?

A

vitamin D receptor (nuclear hormone receptor)

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20
Q

Where does vitamin D2 (ergocalciferol) come from?

A

-plants, fungi, invertebrates

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21
Q

where does vitamin D3 (cholecalciferol) come from?

A

endogenous vitamin D in animals

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22
Q

What is the main storage form of vitamin D and is best for assessing vitamin D nutritional status?

A

25-hydroxyvitamin D (calcidiol)

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23
Q

What is the most biologically active form of vitamin D?

A

1,25 dihydroxyvitamin D (calcitriol)

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24
Q

T/F- calcitriol controls expresssion of 200 genes, is expressed in the brain, prostate, breast, colon and other tissues, and some cancers can convert calcidiol to calcitriol

A

true

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25
Q

T/F- vitamin D cannot be used for psoriasis or auto-immune diseases

A

False, it can be

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26
Q

What role does sunlight play in endogenous synthesis of vit D?

A

UVB converts 7-dehydrocholesterol to previtamin D3, which rapidly converts to D3.
Not active if UV index less than 3

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27
Q

Can you get vit D toxicity from too much sun?

A

no, excess previtamin D3 destroyed by sunlight

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28
Q

What are some exogenous sources of vitamin D?

A

oily fish, eggs, milk, dietary supplements

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29
Q

Where is vitamin D metabolized to 25-OH?

A

liver

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30
Q

where is 25 OH converted to 1,25 dihydroxy vit D?

A

kidney

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31
Q

what regulates conversion to 1,25 dihydroxy vitamin D3?

A

PTH, serum Ca, phosphate

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32
Q

T/F- vitamin D increases absorption of intestinal Ca and Phosphorus as well as renal Ca absorption

A

true

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33
Q

What is a problem with renal failure regarding vit D?

A

decreased conversion to 1,25 dihydroxy vit d

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34
Q

T/F- vit d deficiency is rare

A

False, it is common and increases risk of fractures, osteomalacia, rickets etc.

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35
Q

Vitamin D deficiency is associated with what cancers?

A

colon, pancreas, breast, ovary, Hodgkins lymphoma

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36
Q

T/F- 1,25 dihydroxy is a potent immunomodulator

A

true. For example, monocytes/macrophages up regulate VDR in response to tuberculosis infection

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37
Q

T/F- increased 25-OH vit D is associated with lower multiple sclerosis risk

A

true

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38
Q

Name 7 causes of Vit D deficiency

A

Sunscreen, aging (reduced 7-dehydrocholesterol), skin damage (burns), poor diet (remember that human breast milk contains very low vitamin D!), liver failure (can’t make 25-OH), renal failure, heritable disorders

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39
Q

How do you treat vitamin D deficiency?

A
  • 200 IU children and adults <50 yrs
  • 1000 IU/day if no sun exposure
  • 50,000 IU as a bolus injection
  • sunlight/UV radiation
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40
Q

Should you check 1,25 dihydroxy vit D levels for nutritional status?

A

no

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41
Q

What are 3 debates for vitamin D in healthcare?

A
  1. payors not reimbursing vitamin D testing in many populations
  2. concerns of over aggressive supplementation
  3. where to set reference ranges
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42
Q

At UIHC, what age group gets most vitamin D testing?

A

around 60, more commonly females

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43
Q

What is the major form of vitamin E?

A

alpha-tocapherol

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44
Q

What are dietary sources of vitamin E?

A

vegetable oils, peanuts

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45
Q

What is a common reason for deficiency?

A

diet deficient in leafy green vegetables

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46
Q

What is the main biological function of vitamin E?

A

anti-oxidant (also thought to preserve neurological function)

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47
Q

Is vitamin E deficiency common or rare in U.S.?

A

rare

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48
Q

What conditions can lead to vitamin E deficiency?

A

cholestasis, pancreatitis, cystic fibrosis, abetalipoproteinemia

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49
Q

What are signs of vitamin E deficiency?

A

neurologic (ataxia, neuropathy), hemolytic anemia (infants)

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50
Q

Is vitamin E toxicity a common problem?

A

no, its rare

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51
Q

What are complications of vitamin E toxicity?

A

coagulopathy, decreased wound healing. infants given too much vit E have higher incidence of sepsis and necrotizing entercolitis

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52
Q

Where is vitamin K1 (phylloquinone) found?

A

plants! cabbage, cauliflower, spinach. also in pork, liver, soybeans, vegetable oils. Low amounts in breast milk

53
Q

Where is vitamin K2 found or produced?

A

produced in intestinal tract by gram positive bacteria

54
Q

Is k3 (synthetic) still used in the united states?

A

no

55
Q

What lipid soluble vitamin does the body hold the shortest reserve of? How long is it?

A

vitamin K, 3 week reserve

56
Q

Name 2 biological functions f vitamin K

A
  1. required for gamma-carboxylation of glutamate side chains of some clotting factors (II, VII, IX, X, C, S)
  2. modified glutamic acid residues (gamma-carboxyglutamic acid binds calcium, allowing cross-bridge with phospholipids
57
Q

Symptom of vitamin K

deficiency?

A

usually hemorrhage (ecchymosis, epistaxis, intestinal bleeding)

58
Q

What age group is at particularly high risk and routinely given vit K?

A

infants (intestinal flora not developed to make vitamin K2, breast milk low in vitamin K)

59
Q

Warfarin blocks what enzyme?

A

VKOR (mutations in VKOR can cause resistance)

60
Q

What is an overdose of warfarin treated with?

A

vitamin K and/or fresh frozen plasma (provides clotting factors)

61
Q

T/F- vitamin K toxicity is rare but associated with hemolytic anemia in infants

A

true

62
Q

T/F- cystic fibrosis is likely associated with combined deficiency of vitamins ADEK?

A

true

63
Q

What would be an appropriate indication for 1,25 dihydroxy vitamin D plasma level test?

A

renal failure with persistent hypocalcemia

64
Q

Is vitamin C synthesized endogenously in humans?

A

no

65
Q

Name 3 biological functions of vitamin C

A

anti-oxidant, improves absorption of non-heme dietary iron, and involved in multiple biochemical pathways
(involved in hydroxylation of pro collagen to collagen)

66
Q

Is vitamin C deficiency rare or common in USA?

A

rare (scurvy)

67
Q

What populations are at risk for vitamin C deficiency?

A

elderly, those on restricted diets, alcoholics

68
Q

Symptoms of scurvy?

A
  • perifollicular hemorrhage
  • coiled body hairs
  • ecchymoses
  • xerosis (dry skin)
  • poor wound healing
  • gum abnormalities
69
Q

Problems with vitamin C toxicity?

A

high doses acidify urine and promote iron overload in pts with thalassemia and hematochromatosis. DOES NOT CAUSE KIDNEY STONES

70
Q

What is another name for vitamin B1?

A

thiamine

71
Q

Is B1 water soluble?

A

yes

72
Q

What foods is B1 found in?

A

yeast, grains, peas, potatoes, vegetables

73
Q

T/F- B1 is leached out of food after being washed or boiled

A

true

74
Q

T/F- B1 is transported in plasma as thiamine and phosphorylated in tissue

A

true

75
Q

What is the purpose of Thiamine triphosphate (TTP)?

A

involved in nerve conduction (Na+ channels)

76
Q

What is the purpose of thiamine pyrophosphate (TPP)?

A

carbohydrate pathways, branched chain amino acids

77
Q

Name the symptoms of thiamine deficiency in infants

A

dyspnea, cyanosis, diarrhea, vomiting, wasting

78
Q

What populations is thiamine deficiency common in? What does this cause?

A
  • Elderly and alcoholics
  • Dry beriberi: poor appetite, fatigue, peripheral neuritis
  • Wet beriberi: edema and cardiac failure
79
Q

What populations is Wernicke Korsakoff syndrome common in?

A

alcohoilics, AIDS

-exacerbated by magnesium deficiency

80
Q

Compare wernicke encephalopathy to korsakoff syndrome

A
  • wernicke encephalopathy: confusion, ataxia, opthalmoplegia

- Korsakoff syndrome: short term memory loss, confabulation (spontaneous narration of events that never happened.

81
Q

Is thiamine toxicity common?

A

No but it can cause headache, convulsions, cardiac arrhythmias, and neuromuscular collapse when it does happen

82
Q

What is vitamin B2 known as?

A

riboflavin

83
Q

What are the cofactor forms of B2 (riboflavin)?

A

flavin mononucleotide (FMN) and flavin adenine nucleotide (FAD)

84
Q

What foods are high in B2?

A

milk, liver, eggs, vegetables

85
Q

Is B2 stable to heat?

A

yes

86
Q

Does B2 degrade in milk if exposed to light?

A

yes

87
Q

What are the biological functions of riboflavin (B2)?

A
  • cofactors for large group of flavoproteins
  • flavoproteins funciton in redox rxns (respiratory enzymes, iron metabolism, pyridoxine metabolism, folate metabolism, xenobiotic detoxification)
88
Q

What two factors put people at risk for riboflavin (B2) deficiency?

A

poverty and poor diet

89
Q

What are symptoms of riboflavin deficiency?

A

angular stomatitis, glossitis, photophobia, blepharospasm, dermatological changes, neurological changes (behavior, neuropathy, EEG changes)

90
Q

Is riboflavin toxicity common?

A

NO, very rare, little evidence for distinct overdose syndrome

91
Q

What is vitamin B3 also known as?

A

niacin

92
Q

B3 (niacin) is a derivative of what?

A

pyridine

93
Q

B3 deficiency is associated with what?

A

poor diet

94
Q

What are the active cofactor forms of B3?

A

NAD and NADP

95
Q

Can NAD and NADP be made from anything beside B3?

A

yes, tryptophan

96
Q

Name the 3 D’s associated with Niacin deficiency (pellagra)?

A

-diarrhea, dermatitis (+glossitis, stomatitis), dementia

97
Q

T/F- carcinoid tumors can predispose to niacin deficiency due to accelerate tryptophan metabolism

A

true

98
Q

T/F- gram doses of niacin used for lipid disorders can cause flushing, wheezing, headache, GI discomfort, liver toxicity

A

true (can premedicate with aspirin/NSAIDs to prevent these effects)

99
Q

What enzymes should you monitor for someone on high dose niacin therapy?

A

liver enzymes

100
Q

What is B6 also known as?

A

pyridoxine

101
Q

What are dietary sources of B6?

A

meats, vegetables

102
Q

What two liver enzymes is B6 important for synthesizing?

A

ALT/AST

103
Q

T/F- B6 is needed for the conversion of tryptophan to serotonin or to niacin

A

true

104
Q

Symptoms of vitamin B6 deficiency in infants?

A

-irritability, seizure, anemia, vomiting, ataxia, abdominal pain

105
Q

Symptoms of B6 deficiency in adults? Predisposing factors?

A
  • Sx: facial seborrhea, peripheral neuropathy

- Predisposing factors: celiac disease, ulcerative colitis, lactation, alcoholism

106
Q

T/F- pyridoxine deficiency in pregnant women associated with poor birth outcomes?

A

true

107
Q

What drugs antagonize pyridoxine?

A

isoniazid, corticosteroids, penicillamine

108
Q

Symptoms of B6 toxicity?

A

RARE-tachypnea and neuropathy

109
Q

Name 2 therapeutic uses of B6

A
  • hyperemesis gravidarum (nausea and vomiting in pregnancy)

- seizure control in early childhood (only vitamin deficiency linked to seizures)

110
Q

What is B12 also called?

A

cobalamin

111
Q

Dietary sources of cobalamin?

A

meat (liver), dairy

112
Q

T/F- B12 deficiency is rare in vegetarians

A

False. 2/3 of vegetarians have deficiency

113
Q

What is pernicious anemia?

A

autoimmune disorder with gastric atrophy and decreased/absent intrinsic factor

114
Q

Where does B12/IF absorption occur?

A

ileum

115
Q

What is b12 carried in the plasma by?

A

transcobalamins

116
Q

What 2 biochemical reactions require B12?

A
  1. conversion of methylTHF to TFH
    - >secondarily converts homocysteine to methionine
  2. methylmalonyl-CoA to Succinyl-CoA
117
Q

How long to become deficient in B12?

A

2-4 years

118
Q

Does B12 have low or high toxicity?

A

very low toxicity

119
Q

Folic acid is vitamin precursor to what?

A

tetrahydrofolate

120
Q

Source of folate in diet?

A

liver and green vegetables, breads and grains now supplemented

121
Q

Are folates absorbed as mono or polyglutamates?

A

converted to monoglutamates in the gut and absorbed in the ileum then converted to polyglutamates in tissues

122
Q

Functional activation of folic acid requires what?

A

B12

123
Q

Examples of folate antagonists?

A

trimethoprim and methotrexate

124
Q

What do folate antagonists inhibit?

A

TFH reductase

125
Q

Who should be supplemented with folate?

A

pregnant women, premature infants, and patients with chronic hemolysis

126
Q

T/F- cyanocobalamin (B12) can only be given separately as intramuscular injection

A

true

127
Q

What is a caution about multivitamins?

A

possibility of vitamin A toxicity and on patients with warfarin (vitamin K reduces effectiveness)

128
Q

Most common vitamin deficiency in a strict vegetarian who doesn’t eat eggs?

A

B12

3 Path Unit (5 decks)

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