Vitamins

Question 1

Vitamin D functions

Answer 1

Intestine 
--Increases Ca++ uptake
--Increases Phosphate and Mg2+ absorption 
Kidney
--Stimulates PTH--> reabsorption of Ca++
Bone 
--Reabsorption of Ca++

Question 2

Vitamin D deficiency

Answer 2

• -Rickets (children)

- -Osteomalacia (adults)

Question 3

Vitamin D toxicity

Answer 3

• -Hypercalcemia

- -Sarcoidosis and excess supplementation are possible

Question 4

Vitamin K functions

Answer 4

• -Post-translational modification of various clotting factors (proteins C and S, prothrombin, II, VII, IX, X
• -Synthesized by intestinal factors

Question 5

Vitamin K deficiency causes

Answer 5

• -Warfarin
• -Anticonvulsants
• -Antibiotics

Question 6

Vitamin A functions

Answer 6

–Used to treat acne, measles, AML (M3 subtype)

Question 7

Vitamin A deficiency

Answer 7

• -Night blindness
• -Xerophthalmia
• -Keratomalacia
• -Bitot spots

Question 8

Vitamin A toxicity

Answer 8

• -Headache
• -Nausea and vomiting
• -Increase in intracranial pressure
• -Dry and pruritic skin
• -Hepatomegaly
• -+/- cirrhosis
• -Bone and joint pain
• -Alopecia
• -TERATOGENIC

Question 9

Vitamin E (Alpha-tocopherol) deficiency

Answer 9

• -Hemolytic anemia
• -Spinocerebellar degeneration (ataxia)
• -Peripheral neuropathy
• -Proximal muscle weakness

Question 10

Vitamin C (ascorbic acid) function

Answer 10

• -Hydroxylation of proline and lysine residues of collagen
• -Required in conversion of dopamine –> NE
• -Antioxidant
• -Facilitates iron absorption in gut

Question 11

Vitamin C deficiency

Answer 11

• -Anemia
• -Sore, spongy gums
• -Loose teeth
• -Fragile blood vessels
• -Hemarthrosis
• -Impaired wound healing
• -Swollen joints

Question 12

Vitamin B1 (thiamine) functions

Answer 12

• -Active form: thiamine pyrophosphate

- –Cofactor with pyruvate dehydrogenase, alpha ketoglutarate dehydrogenase, transketolase

Question 13

Vitamin B1 (thiamine) deficiency

Answer 13

• -Occurs with poor nutrition (alcoholism), malabsorption
• -Damage of medial thalamus and mamillary bodies of posterior hypothalamus
• -Wernicke-Korsakoff syndrome
• -Beriberi

Question 14

Wet beriberi

Answer 14

• -Peripheral vasodilation
• -High output heart failure
• -Edema
• -Cardiomegaly

Question 15

Dry beriberi

Answer 15

• -Peripheral neuropathy
• -Muscle weakness
• -Hyporeflexia or areflexia

Question 16

Vitamin B2 (riboflavin) function

Answer 16

• -Active forms: flavin mononucleotide (FMN) or flavin adenine dinulcleotide (FAD)
• -Cofactors for redox reactions (if enzyme has dehydrogenase in name, likely requires riboflavin)

Question 17

Vitamin B3 (niacin) function

Answer 17

• -Active forms: Nicotinamide adenine dinucleotide (NAD) and Nicotinamide adenine dinucleotide phosphate (NADP)
• -Important in redox reactions
• -Derived from tryptophan
• -Used in patients with dyslipidemia

Question 18

Vitamin B3 (niacin) deficiency

Answer 18

• -Pellagra (dementia, diarrhea, dermatitis)

- -Can be caused by dietary deficiency, Hartnup disease, Malignant carcinoid syndrome, Isoniazid (inhibits B3 and B6)

Question 19

Vitamin B5 (pantothenate) function

Answer 19

–Compound of coenzyme A

Question 20

Vitamin B5 (pantothenate) deficiency

Answer 20

• -Dermatitis
• -Alopecia
• -Adrenal insufficiency
• -Enteritis

Question 21

Vitamin B6 (pyridoxine) function

Answer 21

• -Active form: pyridoxal phosphate
• -Coenzyme for many enzymes especially involved in transaminations and deaminations
• -Conversion of amino acid precursors

Question 22

Vitamin B6 (pyridoxine) deficiency

Answer 22

• -Angular cheilosis
• -Glossitis
• -Convulsions
• -Peripheral neuropathy
• -Hyperirritability
• -Isoniazid can cause deficiency

Question 23

Vitamin B7 (Biotin) function

Answer 23

–Apoenzyme for carboxylation reactions (Enzymes with carboxylase in the name)

Question 24

Vitamin B7 (Biotin) deficiency causes

Answer 24

• -Avidin in egg whites (uncooked) prevents absorption of biotin
• -Antibiotics

Question 25

Vitamin B9 (folic acid) function

Answer 25

- -Synthesis and repair of DNA (purines and pyrimidines) - -Rapid cell division and growth - -Biologically active form is tetrahydrofolate

Question 26

Vitamin B9 (folic acid) deficiency

Answer 26

- -Can be caused by medications or malnutrition - -Can be low in pregnancy - -Neural tube defects in utero - -Growth failure - -Megaloblastic anemia - -Glossitis - -Diarrhea

Question 27

Vitamin B12 (cobalamin) function

Answer 27

- -Cofactor with homocysteine methyltransferase | - -Conversion of MMA to succinyl CoA

Question 28

Vitamin B12 (cobalamin) deficiency

Answer 28

- -Megaloblastic anemia | - -Neuro symptoms: paresthesias, ataxia, memory loss, dementia, severe weakness

Question 29

Vitamin B12 (cobalamin) sources

Answer 29

- -Only found in animal products - -Supplements needed for strict vegans - -Improper absorption most common cause of deficiency