Vitamins

Question 1

which vitamins are fat soluble?

Answer 1

A,D,E,K

Question 2

which vitamins are water soluble?

Answer 2

B vitamins, C

Question 3

describe vitamin A

Answer 3

action: antioxidant, in retinal pigments, differentiation of epithelial cells
treats: measles, AML (M3), topically used for wrinkles/acne

Question 4

what happens with vitamin A deficiency?

Answer 4

• night blindness (nyetalopia)
• dry/scaly skin (xerosis cutis)
• alopecia
• corneal degeneration (keratomalacia)
• immune suppression

Question 5

what happens with excess vitamin A?

Answer 5

• arthralgias
• skin changes
• alopecia
• cerebral edema
• pseudotumor cerebri
• osteoporosis
• hepatic changes
• teratogenic changes

Question 6

describe vitamin B1

Answer 6

=thiamine

-cofactor for pyruvate DH, alpha-KG DH, transketolase, BCKA DH

Question 7

how is vitamin B1 deficiency diagnosed?

Answer 7

by increase in RBC transketolase activity after administering B1

Question 8

what happens in B1 deficiency and what conditions can it cause?

Answer 8

• impaired glucose breakdown -> deplete ATP
• affects highly aerobic tissues first (heart, brain)
• seen in malnutrition and alcoholism

can cause: Wernicke-Korsakoff or wet/dry BeriBeri

Question 9

describe Wernicke-Korsakoff symptoms

Answer 9

• confusion
• confabulation
• ataxia
• ophthalmoplegia
• memory/personality changes

Question 10

describe wet vs. dry beriberi

Answer 10

wet: B1 deficiency + high output cardiac failure, edema
dry: B1 deficiency + polyneuritis, symmetrical muscle wasting

Question 11

describe vitamin B2

Answer 11

= riboflavin

-part of FMN, FAD -> cofactor in redox reactions (succinate DH)

Question 12

what happens in B2 deficiency?

Answer 12

“2 C’s for B2”

• cheilosis (inflammation of lips, scaling/fissuring of mouth corners)
• corneal vascularization

Question 13

describe vitamin B3

Answer 13

=niacin

• part of NAD+, NADP+ -> used in redox reactions
• comes from Trp
• its synthesis requires B2 and B6
• treats dyslipidemia (lowers VLDL, raises HDL)

Question 14

what happens in B3 deficiency?

Answer 14

“3 D’s of B3”

• diarrhea, dementia, dermatitis (symptoms of pellagra)
• can be caused by Hartnup disease (loss of Trp absorption)

Question 15

what happens with excess B3?

Answer 15

• facial flushing due to prostaglandins
• hyperglycemia
• hyperuricemia

Question 16

describe vitamin B5

Answer 16

=pantothenate (remember “B5 = PENTOthenate”)

• part of CoA
• essential for FA synthase

Question 17

what happens in B5 deficiency?

Answer 17

• dermatitis
• enteritis
• alopecia
• adrenal insufficiency

Question 18

describe vitamin B6

Answer 18

=pyridoxine

• part of PLP -> for transaminations, decarboxylations, and glycogen phosphorylase
• needed for synthesis of cystathione, heme, niacin, histamine, and some neurotransmitters

Question 19

what happens in B6 deficiency?

Answer 19

• microcytic/sideroblastic anemias
• convulsions
• hyperirritability
• peripheral neuropathy

Question 20

describe vitamin B7

Answer 20

=biotin

-for carboxylations (adds 1C) -pyruvate carboxylase, acetyl-coA carboxylase, propionyl-coA carboxylase

Question 21

what happens in B7 deficiency?

Answer 21

(this is rare)

• dermatitis
• alopecia
• enteritis

Question 22

what can cause B7 deficiency?

Answer 22

• antibiotic use

- excessive ingestion of raw egg whites (contain avidin)

Question 23

describe vitamin B9

Answer 23

=folate/folic acid

• part of THF for 1-C transfer reactions or methylations
• needed for synthesis of N bases in DNA and RNA
• found in leafy green veggies

Question 24

what happens in B9 deficiency?

Answer 24

• macrocytic, megaloblastic anemia
• NO NEURO SYMPTOMS
• increased HomoCys levels, but normal methylmalonyl levels
• hypersegmented PMNs

*most common vitamin deficiency in U.S.

Question 25

what can cause B9 deficiency?

Answer 25

- pregnancy (can cause neural tube defects in child - spina bifida) - alcoholism - the drugs phenytoin, sulfonamides, methotrexate

Question 26

describe vitamin B12

Answer 26

= cobalamin - cofactor for HomoCys methyltransferase and methylmalonyl-coA mutase - found in animal products - large reserve stored in liver

Question 27

what happens in B12 deficiency?

Answer 27

- macrocytic, megaloblastic anemia - NEURO SYMPTOMS - increased HomoCys AND methylmalonyl levels - hypersegmented PMNs - prolonged deficiency leads to irreversible nerve damage

Question 28

what can cause B12 deficiency?

Answer 28

- insufficient intake (veganism) - malabsorption - lack of intrinsic factor (pernicious anemia, gastric bypass) - absence of terminal ileum (Crohn's)

Question 29

what is diagnostic for pernicious anemia?

Answer 29

anti-intrinsic factor antibodies

Question 30

describe vitamin C

Answer 30

= ascorbic acid - antioxidant - reduces iron to Fe2+ state for absorption - needed for hydroxylation of Pro and Lys (collagen) - needed for dopamine B-hyroxylase (dopamine -> norepi)

Question 31

what happens in vitamin C deficiency?

Answer 31

- scurvy (swollen gums, bruising, hemarthrosis, anemia, poor wound healing, "corkscrew" gait) - weakened immune response

Question 32

what happens with excess vitamin C?

Answer 32

- nausea, vomiting, diarrhea - fatigue - calcium oxalate nephrolithiasis - increased risk of Fe toxicity

Question 33

describe vitamin D

Answer 33

- D2 = ergocalciferol (ingested from plants) - D3 = cholecalciferol (ingested from milk, formed by sun) - increases intestinal absorption of calcium, phosphate - increases bone mineralization

Question 34

what are the storage and active forms of D3?

Answer 34

storage: 25-OH D3 active: 1,25-(OH)2 D3 (calcitriol)

Question 35

what happens in vitamin D deficiency?

Answer 35

- Rickets in kids (bone pain/deformity) - osteomalacia in adults (bone pain/muscle weakness) - hypocalcemic tetany exacerbated by low sun exposure, pigmented skin, prematurity

Question 36

what happens with excess vitamin D?

Answer 36

- hypercalcemia - hypercalciuria - loss of appetite - stupor seen in sarcoidosis

Question 37

describe vitamin E

Answer 37

=tocopherol, tocotrienol - antioxidant (protects RBCs and membranes from ROS) - can enhance anticoagulant effects of warfarin/Coumadin

Question 38

what happens in vitamin E deficiency?

Answer 38

- hemolytic anemia - acanthocytosis - muscle weakness - posterior column and spinocerebellar tract demyelination neuro presentation similar to B12 deficiency, but no megaloblastic anemia or increased serum methylmalonyl

Question 39

describe vitamin K

Answer 39

-cofactor for gamma carboxylations in blood clotting -needed for activation of clotting factors 2,7,9,10 and proteins C and S (warfarin = vitamin K antagonist) -made by intestinal flora

Question 40

what happens in vitamin K deficiency?

Answer 40

- neonatal hemorrhage with increased PT and aPTT (increased clotting time) but normal bleeding time - also caused by prolonged use of broad-spectrum antibiotic

Question 41

describe zinc

Answer 41

- essential for 100+ enzymes | - important in forming zinc fingers (DNA-binding domains)

Question 42

what happens in zinc deficiency?

Answer 42

- delayed wound healing - hypogonadism - decreased adult hair - dysgeusia - anosmia - acrodermatitis enteropathica -predisposes to alcoholic cirrhosis

Question 43

what happens in copper deficiency and copper excess?

Answer 43

def: Menke's disease (hair, collagen defects) excess: Wilson's disease (brain, liver toxicity, caused by defective transport protein -> Cu accumulates in liver)

Question 44

what happens in iodine deficiency?

Answer 44

goiter and hypothyroidism

Question 45

what is cobalt needed for?

Answer 45

component of B12