Vitamins Flashcards

1
Q

Fat soluble vitamins

A

Vitamins A,D,E, and K

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2
Q

Two water soluble vitamins that are stored in the liver

A

B12 and folate

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3
Q

4 major functions of vitamin A

A

Antioxidant

Constituent of visual pigments (retinal)

Essential for normal differentiation of epithelial cells

Prevents squamous metaplasia

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4
Q

Two conditions that can be treated with vitamin A

A

Measles and AML, subtype M3

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5
Q

Symptoms of vitamin A deficiency

A

Night blindness, dry skin, keratomalacia, squamous metaplasia

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6
Q

Symptoms of vitamin A excess

A

Arthralgias, fatigue, headaches, skin changes, sore throat, alopecia,

Teratogenic (cleft palate, cardiac abnormalities): pregnancy test and two forms of contraception are needed before isotretinoin is used for severe acne

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7
Q

4 enzymes that use vitamin B1 as a cofactor

A

Pyruvate dehydrogenase (links glycolysis to TCA)
Alpha-ketoglutarate dehydrogenase (TCA)
Transketolase (HMP shunt)
BCAA dehydrogenase

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8
Q

3 conditions seen in vitamin B1 deficiency

A

Wernicke-Korsakoff: confusion, ophthalmoplegia, ataxia (classic triad) + confabulation, personality change, memory loss (permanent)

Dry beriberi: polyneuritis, symmetrical muscle wasting

Wet beriberi: high output cardiac failure (dilated cardiomyopathy), edema

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9
Q

Condition seen with chronic thiamine deficiency that affects cerebellum

A

Alcoholic cerebellar degeneration: loss of Purkinje cells in anterior lobes and vermis

Causes progressive, wide-based gait ataxia, truncal instability, intention tremor

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10
Q

Function of vitamin B2 (riboflavin)

A

Cofactor in oxidation and reduction (e.g. FADH2)

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11
Q

Symptoms of B2 deficiency

A

Cheilosis (inflammation of lips, scaling and fissures at the corners of the mouth), corneal vascularization, magenta colored tongue

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12
Q

Function of vitamin B3 (niacin)

A

Constituent of NAD+ ,NADP+ (used in redox reactions)

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13
Q

Amino acid necessary for synthesis of niacin

A

Tryptophan, also requires vitamin B6

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14
Q

Symptoms of niacin deficiency

A

Glossitis and severe deficiency leads to pellagra (diarrhea, dermatitis, dementia)

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15
Q

Conditions where niacin deficiency may be seen

A

Hartnup’s (decreased tryptophan absorption), malignant carcinoid syndrome (increased tryptophan metabolism), and isoniazid therapy (decreased B6)

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16
Q

Symptoms of niacin excess

A

Facial flushing (can prevent with aspirin pre-treatment)

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17
Q

Function of vitamin B5 (pantothenate)

A

Essential component of CoA (a cofactor for acyl transfers) and fatty acid synthase

18
Q

Symptoms of vitamin B5 defieciency

A

Dermatitis, enteritis, alopecia, adrenal insufficiency

19
Q

Function of vitamin B6 (pyridoxine)

A

Cofactor used in transamination reactions, decarboxylation reactions, and glycogen phosphorylase

20
Q

Symptoms of vitamin B6 deficiency

A

Convulsions, hyperirritability, peripheral neuropathy (seen in isoniazid use), sideroblastic anemias due to impaired hemoglobin synthesis and iron excess

21
Q

Function of vitamin B7 (biotin)

A

Cofactor for carboxylation enzymes including:

1) pyruvate carboxylase
2) acetyl-CoA carboxylase
3) propionyl-CoA carboxylase

22
Q

Function of vitamin B9 (folic acid)

A

Converted to THF, a coenzyme for 1 carbon transfers/methylation reactions

Also important for synthesis of nitrogenous bases in DNA and RNA

23
Q

Symptoms of folic acid deficiency

A

Macrocytic, megaloblastic anemia (no neurologic symptoms), homocysteinemia (increased risk for DVT and atherosclerosis)

24
Q

Function of vitamin B12

A

Cofactor for homocysteine methyltransferase (transfers methyl groups) and methylmalonyl-CoA mutase

25
Symptoms of B12 deficiency
Macrocytic, megaloblastic anemia with hypersegmented neutrophils (paressthesias, subacute combined degeneration)
26
Cause of B12 deficiency seen with normal urinary excretion of radiolabeled B12
Poor B12 intake
27
Cause of B12 deficiency seen with diminished urinary excretion of radiolabeled B12
Impaired intestinal absorption
28
Cause of B12 deficiency seen with with normal urinary excretion after addition of intrinsic factor
Pernicious anemia
29
Cause of B12 deficiency seen with diminished urinary excretion after addition of intrinsic factor
Malabsorption syndrome such as pancreatic insufficiency, bacterial overgrowth, or short gut syndrome
30
4 functions of vitamin C
Antioxidant Facilitates iron absorption Hydroyxlation of proline and lysine in collagen synthesis Necessary for dopamine hydroxylase which converts DA to NE
31
Symptoms of vitamin C deficiency
Scurvy: swollen gums, bruising, hemarthrosis, anemia, poor wound healing, weakened immune response Collagen synthesis defect
32
Symptoms of vitamin C excess
N/V, diarrhea, fatigue, sleep problems Can increase risk of iron toxicity in predisposed people (those with transfusions, hereditary hemochromatosis)
33
Function of vitamin D
Increases intestinal absorption of calcium and phosphate, and increases bone mineralization
34
Symptoms of vitamin D deficiency
Rickets (children, bone pain and deformities) and osteomalacia (adults, bone pain and weakness), hypocalcemic tetany Breast milk has low vitamin-D (must supplement in dark-skin peopled)
35
Symptoms of vitamin D excess
Hypercalcemia, hypercalciuria, loss of appetite, stupor
36
Disease that can cause vitamin D excess
Sarcoidosis: increases activation of vitamin D by epithelioid macrophages
37
Function of vitamin E
Antioxidant (protects RBCs and membranes from free-radical damage)
38
Symptoms of vitamin E deficiency
Increased fragility of RBCs (hemolytic anemia), muscle weakness, posterior column and spinocerebellar tract demyelination, infertility
39
Symptoms of vitamin E excess
Potential hemorrhage in warfarin patients
40
Function of vitamin K
Catalyzes gamma-carboxylation of glutamic acid residues on various proteins associated with blood clotting
41
Symptoms of vitamin K deficiency
Neonatal hemorrhage with prolonged PT and aPTT but normal bleeding time