Biochemistry- Nutrition

Question 1

Vitamins: fat soluble

Answer 1

A, D, E, K. Absorption dependent on gut and

pancreas.

Question 2

B-complex deficiencies often result in…

Answer 2

dermatitis, glossitis, and diarrhea.

Question 3

Wich Vitamins: water soluble wash out easily from body

Answer 3

All except B12 and B9 (folate). B12 stored in liver for ~ 3–4 years. B9 stored in liver for ~ 3–4 months

Question 4

Vitamins: water

soluble

Answer 4

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 5

Vitamin A (retinol) FUNCTION

Answer 5

• constituent of visual pigments
• essential for normal differentiation of epithelial cells into specialized tissue.
• prevents squamous metaplasia.
• Used to treat measles and acute promyelocytic leukemia (APL).

Question 6

Use oral isotretinoin to treat..

Use all-trans retinoic acid …

Answer 6

1. severe cystic acne.

2. to treat acute promyelocytic leukemia

Question 7

Vitamin A (retinol) DEFICIENCY

Answer 7

(nyctalopia) ; (xerosis cutis); corneal degeneration

(keratomalacia) ; Bitot spots on conjunctiva; immunosuppression

Question 8

Vitamin A (retinol) EXCESS

Answer 8

Acute toxicity—nausea, vomiting, vertigo, and blurred vision.

Chronic toxicity—alopecia, dry skin (eg, scaliness), hepatic toxicity and enlargement, arthralgias, and pseudotumor cerebri.

Isotretinoin is teratogenic.

Question 9

Vitamin B1 (thiamine)FUNCTION

Answer 9

Think ATP: α-ketoglutarate dehydrogenase,

Transketolase, and Pyruvate dehydrogenase.

Question 10

Vitamin B1 (thiamine) DEFICIENCY

Answer 10

Spell beriberi as Ber1Ber1 to remember
vitamin B1

Wernicke-Korsakoff syndrome—confusion,
ophthalmoplegia, ataxia (classic triad)

Dry beriberi—polyneuritis, symmetrical muscle
wasting.

Wet beriberi—high-output cardiac failure
(dilated cardiomyopathy), edema.

Question 11

Vitamin B2 (riboflavin)
FUNCTION

Answer 11

FAD and FMN are derived from riboFlavin
(B2 ≈ 2 ATP).

Component of flavins FAD and FMN, used as
cofactors in redox reactions.

Question 12

Vitamin B2 (riboflavin)
DEFICIENCY

Answer 12

The 2 C’s of B2.

Cheilosis (inflammation of lips, scaling and
fissures at the corners of the mouth), Corneal
vascularization.

Question 13

Vitamin B3 (niacin)
FUNCTION

Answer 13

NAD derived from Niacin (B3 ≈ 3 ATP).

Derived from tryptophan. Synthesis requires vitamins B2 and B6. Used to treat dyslipidemia.

Question 14

Vitamin B3 (niacin)
DEFICIENCY

Answer 14

The 3 D’s of B3.

Symptoms of pellagra: Diarrhea, Dementia , Dermatitis (C3/C4 dermatome circumferential “broad collar” rash).

Can be caused by Hartnup disease, malignant carcinoid syndrome (􀁱 tryptophan metabolism), and isoniazid (􀁲 vitamin B6).

Question 15

Vitamin B3 (niacin)

Answer 15

Facial flushing, hyperglycemia, hyperuricemia.

Question 16

Hartnup disease

Answer 16

disease—autosomal recessive. Deficiency of neutral amino acid (eg, tryptophan).
Pellagra-like symptoms. Treat with highprotein diet and nicotinic acid.

Question 17

Vitamin B5 (pantothenic acid)FUNCTION

Answer 17

B5 is “pento”thenic acid.

Essential component of coenzyme A (CoA, a cofactor for acyl transfers) and fatty acid synthase.

Question 18

Vitamin B5 (pantothenic acid) DEFICIENCY

Answer 18

Dermatitis, enteritis, alopecia, adrenal

insufficiency.

Question 19

Vitamin B6 (pyridoxine) FUNCTION

Answer 19

Cofactor used in transamination (eg, ALT and AST),
decarboxylation reactions, glycogen phosphorylase.

Synthesis of cystathionine, heme, niacin, histamine, and neurotransmitters including serotonin, epinephrine, norepinephrine (NE), dopamine, and GABA.

Question 20

Vitamin B6 (pyridoxine) DEFICIENCY

Answer 20

Convulsions, hyperirritability, peripheral neuropathy (deficiency inducible by isoniazid and oral contraceptives), sideroblastic anemias due to impaired hemoglobin synthesis and iron excess.

Question 21

Vitamin B7 (biotin)FUNCTION

Answer 21

Cofactor for carboxylation enzymes:
􀂃 Pyruvate carboxylase
􀂃 Acetyl-CoA carboxylase
􀂃 Propionyl-CoA carboxylase

Question 22

Vitamin B7 (biotin) DEFICIENCY

Answer 22

Rare. Dermatitis, alopecia, enteritis. Caused by antibiotic use

Question 23

Vitamin B9 (folate) FUNCTION

Answer 23

Important for the synthesis of nitrogenous bases
in DNA and RNA.

Absorbed in jejunum.

Question 24

Vitamin B9 (folate)DEFICIENCY

Answer 24

• Macrocytic, megaloblastic anemia; hypersegmented
  (PMNs); glossitis; no neurologic symptoms (as opposed to vitamin B12 deficiency).
• Labs: 􀁱 homocysteine, normal methylmalonic acid
  levels.
• Seen in alcoholism and pregnancy.

Question 25

Vitamin B12 (cobalamin) FUNCTION

Answer 25

Cofactor for methionine synthase and methylmalonyl-CoA mutase. Important for DNA synthesis.

Question 26

Vitamin B12 (cobalamin) DEFICIENCY

Answer 26

Macrocytic, megaloblastic anemia; hypersegmented PMNs; paresthesias and subacute combined degeneration due to abnormal myelin.

Question 27

``` Vitamin C (ascorbic acid) FUNCTION ```

Answer 27

Antioxidant; facilitates iron absorption by reducing it to Fe2+ state. Hydroxylation of proline and lysine in collagen synthesis. Necessary for dopamine β-hydroxylase, which converts dopamine to NE. Ancillary treatment for methemoglobinemia by reducing Fe3+ to Fe2+.

Question 28

``` Vitamin C (ascorbic acid) DEFICIENCY ```

Answer 28

Vitamin C deficiency causes sCurvy due to a | Collagen synthesis defect.

Question 29

Vitamin C (ascorbic acid) EXCESS

Answer 29

Nausea, vomiting, diarrhea, fatigue, calcium oxalate nephrolithiasis.

Question 30

Scurvy

Answer 30

Swollen gums, bruising, petechiae, hemarthrosis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, “corkscrew” hair.

Question 31

Vitamin D FUNCTION

Answer 31

intestinal absorption of calcium and phosphate, 􀁱 bone mineralization at low levels, 􀁱 bone resorption at higher levels.

Question 32

Vitamin D DEFICIENCY

Answer 32

Rickets in children, osteomalacia in adults, hypocalcemic tetany.

Question 33

Vitamin D EXCESS

Answer 33

Hypercalcemia, hypercalciuria, loss of appetite, stupor. Seen in granulomatous disease

Question 34

Vitamin E (tocopherol/tocotrienol) FUNCTION

Answer 34

Antioxidant. High-dose supplementation may alter | metabolism of vitamin K 􀁰 enhanced anticoagulant effects of warfarin.

Question 35

Vitamin E (tocopherol/tocotrienol) DEFICIENCY

Answer 35

Hemolytic anemia, acanthocytosis, muscle weakness, posterior column and spinocerebellar tract demyelination. Aumented serum methylmalonic acid levels.

Question 36

Vitamin K (phytomenadione, phylloquinone, phytonadione) FUNCTION

Answer 36

cofactor for the γ-carboxylation of glutamic acid residues. Maturation of clotting factors II, VII, IX, X, and proteins C and S.

Question 37

Vitamin K (phytomenadione, phylloquinone, phytonadione) DEFICIENCY

Answer 37

Neonatal hemorrhage with 􀁱 PT and 􀁱 aPTT but normal bleeding time.

Question 38

Zinc FUNCTION

Answer 38

Mineral essential for the activity of 100+ enzymes. Important in the formation of zinc fingers

Question 39

Zinc DEFICIENCY

Answer 39

Delayed wound healing, hypogonadism, 􀁲 adult hair (axillary, facial, pubic), dysgeusia, anosmia, acrodermatitis enteropathica.

Question 40

Protein-energy malnutrition

Answer 40

Protein malnutrition

Question 41

Kwashiorkor

Answer 41

Protein malnutrition ``` MEALS: Malnutrition Edema Anemia Liver (fatty) Skin lesions (hyperkeratosis/ hyperpigmentation) ```

Question 42

Marasmus

Answer 42

Malnutrition not causing edema. Diet is deficient in calories but no nutrients are entirely absent.

Question 43

Fomepizole

Answer 43

FOMEpizole—inhibits alcohol dehydrogenase and is an antidote For Overdoses of Methanol or Ethylene glycol.

Question 44

Disulfiram

Answer 44

inhibits acetaldehyde dehydrogenase (acetaldehyde accumulates, contributing to hangover symptoms), discouraging drinking.

Question 45

Ethanol metabolism increase NADH/NAD+ ratio in | liver, causing:

Answer 45

- Pyruvate to lactate (lactic acidosis) - Oxaloacetate to malate (prevents gluconeogenesis 􀁰 fasting hypoglycemia). - Dihydroxyacetone phosphate to glycerol- 3-phosphate (combines with fatty acids to make triglycerides 􀁰 hepatosteatosis). - NADH leads to aumented utilization of acetyl-CoA for ketogenesis (􀁰 ketoacidosis) and lipogenesis (􀁰 hepatosteatosis)..