Vitamins

Question 1

Water-soluble vitamin names

Answer 1

B1 (thiamine; TPP)
B2 (Riboflavin; FAD, FMN)
B3 (Niacin; NAD+)
B5 (Pantothenic acid; CoA)
B6 (Pyridoxine; PLP)
B7 (Biotin)
B9 (Folate)
B12 (Cobalamin)
C (Ascorbic acid)

Question 2

Vitamin A (retinol)
[fxn, food]

Answer 2

> Antioxidant; found in visual retinal pigments.
Needed for differentiation of epithelial cells in specialized tissues (pancreatic, mucus cells).
Prevents squamous metaplasia.
Found in liver and leafy veggies.

Question 3

Vitamin A

[toxicity]

Answer 3

> Acute: N/V, blurred vision, vertigo
Chronic: alopecia, dried skin, hepatic toxicity and enlargement; pseudotumor cerebri (papilledema w/ benign intracranial HTN)
Teratogenic (cleft palate, cardiac abnormalities, microcephaly)

Question 4

Vitamin A

[deficiency]

Answer 4

Night blindness (nyctalopia)
Dry, scaly skin (xerosis cutis)
Corneal degeneration (keratomalacia)

Question 5

Vitamin B1

[Fxn]

Answer 5

TPP cofactor in pyruvate DHG, alpha-ketoglutarate DHG, branched-chain ketoacid DHG, transketolase

Question 6

Vitamin B1

[Deficiency]

Answer 6

> Wernicke-Korsakoff syndrome
Dry beriberi: polyneuritis, symmetrical muscle wasting
Wet beriberi: high-output cardiac failure (dilated cardiomyopathy), edema
*Seen in malnutrition, alcoholism

Question 7

Vitamin B2

[fxn, deficiency]

Answer 7

> FAD, FMN – cofactors in redox rxns (ex. succinate DHG reaction in TCA cycle).
Def: Cheilosis, corneal vascularization.

Question 8

Vitamin B3

[Fxn]

Answer 8

> NAD+, NADP+ – for redox reactions.
Derived from tryptophan – synthesis needs B2 and B6.
Treat dyslipidemia – lower VLDL, raise HDL

Question 9

Vitamin B3

[deficiency]

Answer 9

> Glossitis.
Severe deficiency can cause Pellagra (ex. Hartnup dse, malignant carcinoid syndrome, isoniazid).
*Pellagra: Diarrhea, Dementia, Dermatitis

Question 10

Vitamin B5

[Fxn, deficiency]

Answer 10

> for CoA, fatty acid synthase.

>Def: dermatitis, enteritis, alopecia, adrenal insufficiency

Question 11

Vitamin B6

[Fxn, deficiency]

Answer 11

> converted to PLP cofactor – transamination (ALT, AST), decarboxylation, glycogen phosphorylation.
synthesis of cystathione, heme, niacin, histamine, neurotransmitters.
Def: convulsions, peripheral neuropathy, sideroblastic anemias (impaired Hgb synth and iron excess).

Question 12

Vitamin B7

[fxn, deficiency]

Answer 12

> Cofactor for pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA carboxylase.
Def: rare; dermatitis, alopecia; antibiotic use or excessive ingestion of raw egg whites (biotin-binding Avidin).

Question 13

Vitamin B9

[fxn, deficiency]

Answer 13

> Converted to THF – for 1-carbon transfer/methylation, synthesis of nitrogenous bases.
Found in leafy green veggies; absorbed in jejenum; storage in liver
Def: MC vit deficiency in US; Megaloblastic anemia w/ no neuro ssx.

Question 14

Vitamin B12

[fxn, deficiency]

Answer 14

> cofactor for homocystine methyltransferase, methylmalonyl-CoA mutase.
found in animal products; synthesized only by microbes
need intrinsic factor for absorption in terminal ileum; storage in liver
Def: megaloblastic anemia w/ neuro ssx; subacute combined degeneration; pernicious anemia (anti-IF antibodies)

Question 15

Vitamin C

[fxn]

Answer 15

> Antioxidant; found in fruits and veggies
needed for iron absorption – reduces iron to Fe2+ state (tx for methemoglobinemia)
hydroxylation of proline and lysine in collagen synthesis.
conversion of dopamine to NE (dopamine B-hydroxylase)

Question 16

Vitamin C

[deficiency, toxicity]

Answer 16

> Def: Scurvy – swollen gums, bleeding, anemia, poor wound healing, corkscrew hair, perifollicular and subperiosteal hemorrhages.
Tox: iron toxicity in predisposed (transfusions), calcium oxalate nephrolithiasis

Question 17

Vitamin D

[fxn]

Answer 17

D2: ergocalciferol (plants)
D3: cholecalciferol (milk, sun-exposed skin)
25-OH D3 (storage)
1,25-(OH)2 D3: calcitriol (active form)
>For intestinal absorption of Ca and phosphate; inc. bone mineralization.
*Breastfed infants should be given oral Vit D

Question 18

Vitamin D

[Deficiency, toxicity]

Answer 18

> Def: Rickets in kids, Osteomalacia in adults

>Tox: seen in granulomatous diseases (inc. activation of Vit D by epithelioid macrophages)

Question 19

Vitamin E (tocopherol/tocotrienol)
[fxn, deficiency]

Answer 19

> Antioxidant (protects RBCs and membranes from free radical damage)
Def: hemolytic anemia, muscle weakness; demyelination of dorsal column, spinocerebellar tract
*Neuro ssx appear w/o megaloblastic anemia, hypersegmented neutrophils, or inc. methylmalonate (vs B12 deficiency)

Question 20

Vitamin K (phytomenadione, phylloquinone, phytonadione)
[fxn]

Answer 20

Cofactor for gamma-carboxylation of glutamate on clotting protein factors.
Synthesized by intestinal flora.
*Warfarin - vit K antagonist

Question 21

Vitamin K

[Deficiency]

Answer 21

Neonatal hemorrhage (inc. PT, aPTT; normal BT)
>Neonates can’t yet synthesize vit K.
>not in breast milk – give vit K injection at birth to prevent hemorrhagic dse of newborn.

Question 22

Zinc

[fxn, deficiency]

Answer 22

> needed for several enzymes; zinc fingers (transcription factor motif)
Def: delayed wound healing, hypogonadism; dec. adult hair; anosmia; acrodermatitis enteropathica

Question 23

Kwashiorkor

Answer 23

PROTEIN malnutrition.
>Skin lesions, edema due to dec. plasma oncotic pressure.
>Liver malfunction (fatty change due to dec. apolipoproteins)
*Small child w/ swollen abdomen.

Question 24

Marasmus

Answer 24

Total CALORIE malnutrition.

>tissue and muscle wasting, loss of subcutaneous fat, edema.