Water soluble vitamins

Question 1

3 general features of WSVs

Answer 1

• precursors to coenzymes involved in intermediary metabolism
• all but vitamin B12 are in vegetables
• deficiency in all but B12 leads to clinical symptoms within weeks due to low body stores

Question 2

Vitamin B1 also called:

Answer 2

thiamine

Question 3

diseases associated with thiamine (B1) deficiency

Answer 3

• Korsakoff’s Disease in alcohol abusers

- Beriberi - peripheral neuropathy and dilated cardiomyopathy

Question 4

thiamine (B1) physiological importance

Answer 4

• coenzyme for enzymes involved in carb metabolism, specifically pyruvate dehydrogenase, a-ketoglutarate dehydrogenase, transketolase

Question 5

vitamin B2 also known as

Answer 5

riboflavin

Question 6

riboflavin (B2) physiological importance

Answer 6

• precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) coenzymes

Question 7

symptoms of riboflavin (B2) deficiency

Answer 7

• fissuring at angles of mouth
• dermatitis
• purple tongue

Question 8

vitamin B3 also known as

Answer 8

Niacin

Question 9

niacin (B3) physiological importance

Answer 9

• precursor to NAD and NADP coenzymes

Question 10

symptoms of niacin (B3) deficiency

Answer 10

• pellagra “sour skin”, dermatitis, diarrhea, dementia, death (lots of D words!)
• Hartnup disease and carcinoid syndrome because of reduced tryptophan uptake/metabolism

Question 11

why is niacin (B3) not really a vitamin?

Answer 11

• body can make it from tryptophan

Question 12

therapeutic use of niacin (B3)

Answer 12

• used to lower LDL and VLDL cholesterol in type 2b hyperlipoproteinemia

Question 13

vitamin B5 also known as

Answer 13

pantothenic acid

Question 14

pantothenic acid (B5) significance

Answer 14

• component of CoA
• no disease associated with deficiency
• found in FAS

Question 15

vitamin B6 compounds

Answer 15

• pyridoxine, pyridoxal, pyridoxamine

- precursors for pyridoxal phosphate, coenzyme for amino acid reactions

Question 16

vitamin B6 therapeutic use

Answer 16

• binds to antituberculous drug Isoniazid

- routine prescribed together with Isoniazid to prevent functional deficiency, characterized by seizures

Question 17

vitamin B7 also known as

Answer 17

Biotin

Question 18

Biotin (B7) physiological significance

Answer 18

• coenzyme in decarboxylation reactions that is covalently bound to specific lysine residues
• found in ACC

Question 19

symptoms of Biotin (B7) deficiency

Answer 19

• caused by eating greater than 20 eggs per day
• eggs contain biotin-binding protein Avidin
• dermatitis, glossitis, nausea

Question 20

vitamin B9 also known as

Answer 20

Folate

Question 21

Folate (B9) physiological importance

Answer 21

• necessary for one carbon metabolism, including purine and thymadine (DNA) synthesis

Question 22

Folate (B9) deficiency

Answer 22

• causes megaloblastic anemia in adults and neural tube defects in fetus

Question 23

folate (B9) therapeutic use

Answer 23

• given in first trimester of pregnancy to prevent defects

- supplemented in enriched foods since 1998

Question 24

vitamin B12 also known as

Answer 24

cobalamin

Question 25

cobalamin (B12) physiological significance

Answer 25

- precursor of methyl cobalamin which is needed to synthesize methionine from homocysteine in blood cells - precursor of deoxyadenosycobalamin, which is needed for fatty acid metabolism in brain cells

Question 26

difference between B12 and other vitamins

Answer 26

- B12 not produced by plants | - requires intrinsic factor for intestinal absorption

Question 27

cobalamin (B12) deficiency

Answer 27

- seen in vegans and those with pernicious anemia (no intrinsic factor) - megaloblastic anemia - subacute combined degeneration of spinal chord - dementia

Question 28

etiology of megaloblastic anemia in B12 deficiency

Answer 28

- lack of B12 blocks metabolism of N5-methyl-tetrahydrofolate which then cannot be used for DNA synthesis - symptoms only appear after years of deficiency due to large body stores

Question 29

treatment of B12 deficiency

Answer 29

- pernicious anemia treated with intramuscular B12 injections, circumvents need for intrinsic factor - folate supplementation ameliorates megaloblastic anemia caused by deficiencies of B12 or folate - folate does not treat spinal chord degeneration

Question 30

vitamin C also known as

Answer 30

ascorbic acid

Question 31

ascorbic acid (C) physiological significance

Answer 31

necessary for post-translational hydroxylation of proline, especially in collagen

Question 32

ascorbic acid (C) deficiency

Answer 32

- scurvy - bleeding gums, hemorrhages around corkscrew hair follicles, bone pain caused by bleeding underneath periosteum, poor wound healing

Question 33

ascorbic acid (C) mega-dose

Answer 33

can cause oxalic acid kidney stones