Nutrition I

Question 1

Describe the absorption of fat soluble vitamins and the cause of their toxicity.

Answer 1

(ADEK)- absorption dependent on gut (ileum) and pancreas. Toxicity is more common than for water soluble vitamins due to accumulation in fat (p.90)

Question 2

Name the 10 water soluble vitamins.

Answer 2

A, 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) (p.90)

Question 3

Which water soluble vitamin is the only one that does not wash out easily and is stored in the liver?

Answer 3

B12 (p.90)

Question 4

Describe three symptoms associated with B-complex deficiencies.

Answer 4

Dermatitis, glossitis, and diarrhea (p.90)

Question 5

What is the function of Vitamin A?

Answer 5

Vitamin A is an antioxidant, is a constituent of visual pigments (retinal), is essential for normal differentiation of epithelial cells into specialized tissue (pancreatic cells, mucus secreting cells), and prevents squamous metaplasia (p.90)

Question 6

What conditions is Vitamin A used to treat?

Answer 6

Measles and AML (subtype M3) (p.90)

Question 7

What foods are rich in Vitamin A?

Answer 7

Liver and leafy vegetables (p.90)

Question 8

What are the symptoms associated with Vitamin A deficiency?

Answer 8

Night blindness, dry skin (p.90)

Question 9

What are the symptoms associated with Vitamin A execss?

Answer 9

Arthralgias, fatigue, headaches, skin changes, sore throat, alopecia. It is a teratogen so negative pregnancy test is required before starting isotretinoin for severe acne (p.90)

Question 10

What is the function of Vitamin B1 (thiamine)?

Answer 10

Part of thiamine pyrophosphate (TPP) which is a cofactor for several enzymes in decarboxylation reactions: pyruvate dehydrogenase (links glycolysis to TCA cycle); a-ketoglutarate dehydrogenase (TCA cycle); Transketolase (HMP shunt); Branched chain amino acid dehydrogenase. All of these enzymes (except for BCAD) are required for ATP synthesis (p.90)

Question 11

Describe the pathology associated with Vitamin B1 deficiency.

Answer 11

Impaired glucose breakdown causes ATP depletion that is worsened by glucose infusion. Highly aerobic tissues (brain and heart) are affected first (p.90)

Question 12

What are the classic symptoms of Wernicke-Korsakoff syndrome?

Answer 12

Confusion, opthalmoplegia, ataxia (the classic triad); confabulation, personality change, memory loss (permanent) (p.90)

Question 13

Describe the pathology associated with Wernicke-Korsakoff syndrome.

Answer 13

Thiamine deficiency causes damage to medial dorsal nucleus of thalamus and mamillary bodies (p.90)

Question 14

What are the symptoms of dry beriberi?

Answer 14

Polyneuritis symmetrical muscle wasting (p.90)

Question 15

What are the symptoms of wet beriberi?

Answer 15

High output cardiac faliure (dilated cardiomyopathy), edema (p.90)

Question 16

What is the function of Vitamin B2 (riboflavin)?

Answer 16

Serves as the cofactor in oxidation and reduction (i.e. FADH2) (p.91)

Question 17

What are the symptoms of vitamin B2 deficiency?

Answer 17

Chelosis (inflamation of the lips, scaling, and fissures at the corners of the mouth); Corneal vascularization (p.91)

Question 18

What is the function of Vitamin B3 (niacin)?

Answer 18

Constituent of NAD+, NADP+ (used in redox reactions) (p.91)

Question 19

What is Vitamin B3 derived from and what cofactor is necessary for its synthesis?

Answer 19

Derived from tryptophan. Synthesis requires vitamin B6 (p.91)

Question 20

What are the symptoms of vitamin B3 deficiency?

Answer 20

Glossitis. Severe deficiency leads to pellagra which is characterized by diarrhea, dementia, and dermatitis (p.91)

Question 21

What can cause Pellagra?

Answer 21

Vitamin B3 deficiency; Hartnup disease (decreased tryptophan absorption), malignant carcinoid syndrome (increased tryptophan metabolism); and Izoniazid (decreased vitamin B6) (p.91)

Question 22

What are the symptoms of vitamin B3 excess?

Answer 22

Facial flushing in pharmacologic doses (p.91)

Question 23

What is the function of Vitamin B5 (pantothenate)?

Answer 23

Essential component of CoA (a cofactor for acyl transfers) and fatty acid synthase (p.91)

Question 24

What are the symptoms of Vitamin B5 deficiency?

Answer 24

Dermatitis, enteritis, alopecia, adrenal insufficiency (p.91)

Question 25

What is the funciton of Vitamin B6?

Answer 25

It is converted to pyridoxal phosphate, a cofactor used in transamination (eg. ALT, AST), decarboylation reactions, glycogen phosphorylase. Synthesis of cystathione, heme, niacin, histamine, and neurotransmitters including serotonin, epinephrine, norepinephrine, and GABA (p.91)