Vitamins

Question 1

B1

Answer 1

Thiamine, TPP
- PD, alpha-KGD, Transketolase (RBC test), branched-chain ketoacid dehydrogenase
Def: Wernicke-Korsakoff, Dry beriberi (polyneuritis, symmetric muscle wasting), Wet beriberi (dilated cardiomyopathy HF, edema)

Dx by increased RBC transketolase activity w/ B1

Question 2

B2

Answer 2

Riboflavin (component of FAD, FMN [=2ATP])
- Succinate dehydrogenase

Def:Cheilosis (inflamed lips, scaling and fissures), Corneal vascularization

Question 3

B3

Answer 3

Niacin (NAD+ [3ATP], NADP+)

• derived from tryptophan, synthesis requires B2 and B6 or diet
• lowers VLDL and raises HDL

Def: glossitis,
Hartnup, malignant carcinoid, isoniazid —- severe def. —-pellagra (Diarrhea, Dementia/hallucinations, Dermatitis (C3/4 broad collar rash= ‘Casal necklace’, hyper pigmentation of sun exposed limbs))

Excess: facial flushing (PG’s NOT histamine - take aspirin w/ niacin), hyperglycemia, hyperuricemia

Question 4

B5

Answer 4

Pantothenic acid (CoA)
- component of CoA and fatty acid synthase
Def: dermatitis, enteritis, alopecia, adrenal insufficiency

Question 5

B6

Answer 5

Pyridoxine (PLP)
- converted to pyridoxal phosphate (PLP) - cofactor in transamination (ALT and AST), decarboxylation, glycogen phosphorylase, synthesis of cystathionine/heme/niacin/histamine/serotonin/Epi/NE/dopamine/GABA

def (caused by isoniazid and OCP): convulsions, hyperirritable, peripheral neuropathy, sideroblastic anemia

Question 6

B7

Answer 6

Biotin
- Pyruvate carboxylase, Acetyl-CoA carboxylase, Propionyl-CoA carboxylase

Def- rare (AB’s or raw eggs whites): dermatitis, alopecia, enteritis, lactic acidosis, surplus of odd chain f.a.’s

Question 7

B9

Answer 7

Folate

• converted to THF
• leafy green vegetables, absorbed in jejunum

Def: increased homocysteine, normal methylmalonic acid

• caused by phenytoin, sulphonamides, methotrexate
• most common def in USA

Question 8

B12

Answer 8

Cobalamin

- cofactor for: homocysteine methyltransferase and methylmalonyl -CoA mutase

Question 9

C

Answer 9

ascorbic acid

• antioxidant, reduces iron to Fe2+ (increases absorption)
• needed for dopamine beta-hydroxylase (dopamine—NE)
• corkscrew hair with scurvy

Excess: calcium oxalate nephrolithiasis, increased risk of Fe toxicity (on top of transfusions, hemochromatosis)

Question 10

A

Answer 10

• Antioxidant
• Treats measles, AML-M3 and acne
• Liver and leafy vegetables
  Def: nyctalopia (night blindness), xerosis cutis (dry scaly skin), keratomalacia (corneal degen.), Bitot spots (conjunctival keratin buildup), immunosuppression

Excess: Acute toxicity, Chronic tox. (alopecia, dry skin, hepatic, pseudotumor cerebri), Teratogenic (cleft palate, cardiac, microcephaly, fetal death)

Question 11

D

Answer 11

D2=ergocalciferol (veg)
D3=cholecalciferol (milk, stratum basale)
25-OH D3=storage form
1,25-(OH)2 D3=calcitrol=active form

Deficiency: exacerbated by pigmented skin, premature
Excess: granulomatous disease (sarcoidosis, TB, Hodgkins and non-Hodgkins lymphoma)

Question 12

E

Answer 12

Tocopherol/tocotrienol
- Antioxidant (protect RBCs), enhances anti-coagulation of warfarin
Def: hemolytic anemia, acanthocytosis, B12 nerve issues

Question 13

K

Answer 13

Phytomenadione, phylloquinone, phytonadione
- gamma carboxylation of glutamic acid residues on clotting factors (2, 7, 9, 10, C, S)
- made by intestinal flora
Def: Neonatal hemorrhage (not retinal) - normal bleeding time, increased PT and PTT

Question 14

Zinc

Answer 14

• 100+ enzymes
• zinc finger (TF motifs)
  Def: delayed wound healing, hypogonadism, decreased adult hair, dysgeusia, anosmia, acrodermatitis enteropathica
  (may predispose to alcoholic cirrhosis)