Nutrition

Question 1

Vitamin A functions

Answer 1

Retinol - antioxidant, visual pigments, normal differentiation of epithelial cells into specialized tissue (pancreatic, respiratory/urinary tracts, occular conjunctiva - prevents metaplasia), TREATS MEASLES and AML

Question 2

Vitamin A deficiency

Answer 2

Night blindness, dry/scaly skin, corneal degneration, immunosuppression

Question 3

Vitamin A excess

Answer 3

Acute (nausea, vomiting, blurred vision) – chronic (alopecia, dry skin, hepatic toxicity, arthralgias, papilledema) – TERATOGENIC! (cleft palate, cardiac abnormalities, microcephaly)

Question 4

Vitamin B1 functions

Answer 4

Thiamine - TPP is cofactor for Pyruvate dehydrogenase, a-ketoglutarate dehydrogenase, transketolase, and branched chain ketoacid dehydrogenase

Question 5

Vitamin B1 deficiency

Answer 5

Impaired glucose breakdown (ATP depletion, worse with glucose infusion) — Wernicke korsakoff syndrome, dry beriberi (polyneuritis), wet berberi (high output cardiac failure, dilated cardiomyopathy) — Diagnose with increase in RBC transketolase activity following vitamin B1

Question 6

Vitamin B2

Answer 6

Riboflavin – makes up FAD and FMN (cofactors) —- deficiency causes cheilosis (inflammation of lips, scaling at corners of mouth), corneal vascularization, dermatitis, and stomatitis

Question 7

Vitamin B3 functions

Answer 7

Niacin - makes up NAD (redox reactions) — made from trytophan (requires vitamin B2 and B6 to make), lowers levels of VLDL and raises HDL

Question 8

Vitamin B3 deficiency

Answer 8

Pellagra (caused by Hartnup disease (decreased tryptophan absorption), malignant carcinoid syndrome (increased tryptophan metabolism), and isoniazid (decreased B6) — 3Ds (Diarrhea, Dementia, Dermatitis - broad collar rash)

Question 9

Vitamin B3 excess

Answer 9

Facial flushing (d/t prostaglandins), hyperglycemia, hyperuricemia

Question 10

Vitamin B5

Answer 10

Pantothenic acid – part of coenzyme A and fatty acid synthase — deficiency causes alopecia, adrenal insufficiency

Question 11

Vitamin B6

Answer 11

Pyridoxine - converted to PLP to use in transamination and glycogen phosphorylase — used to make cystathionine, heme, niacin, histamine, and NTs — deficiency causes convulsions, peripheral neuropathy, sideroblastic anemias

Question 12

Vitamin B7

Answer 12

Biotin - cofactor for carboxylation enzmyes (pyruvate carboxylase, acetal-coa carboxylase, propionyl coa carboylase) — deficiency is rare and caused by raw egg whites

Question 13

Vitamin B9 functions

Answer 13

Folate - converted to tetrahydrofolic acid (coenzyme for 1 carbon transfer/methylation) — important for synthesis of nitrogenous bases – absorbed in jejunum – small pool stored in liver

Question 14

Vitamin B9 deficiency

Answer 14

Macrocytic, megaloblastic anemia, hypersegmented PMNs, glossitis – increased homocysteine but normal methylmalonic acid — seen in alcoholism and pregnancy – MC vitamin deficiency in US

Question 15

Vitamin B12 functions

Answer 15

Cobalamin - Cofactor for homocystine methyltranferase and methylmalonyl-coa mutase — hepatic stores for years

Question 16

Vitamin B12 deficiency

Answer 16

Macrocytic, megaloblastic anemia – hypersegmented PMNs, paresthesia, subacute combined degeneration (dorsal columns, lateral corticospinal tract, spinocerebellar tracts) – increased homocysteine and methylmalonic acid — deficiency d/t veganism, malabsorption, lack of intrinsic factor, or absence of terminal ileum (Crohns)

Question 17

Vitamin C functions

Answer 17

Ascorbic acid - antioxidant, facilitates iron absorption, necessary for hydroxylation of proline and lysine for collagen synthesis, and dopamine B-hydroxylase (dopamine to NE)

Question 18

Vitamin C deficiency

Answer 18

Scurvy - swollen/bleeding gums, bruising, petechiae, anemia, poor wound healing, crokscrew hair

Question 19

Vitamin C excess

Answer 19

Calcium oxalate nephrolithiasis, increase risk of iron toxicity

Question 20

Vitamin D functions

Answer 20

D2 (ergocalciferol from plants), D3 (cholecalciferol from milk and sun exposed skin), 25 OH (storage form in liver), 1, 25 (calcitriol (active from from kidney)) — increase intestinal absorption of calcium and phosphate, increase bone mineralization, decrease PTH

Question 21

Vitamin D deficiency

Answer 21

Rickets in kids, osteomalacia in adults — breastfed infants need supplementation – deficiency worse in low sun exposure, pigmented skin, prematurity

Question 22

Vitamin D excess

Answer 22

Hypercalcemia, hypercalciuria, loss of appetite, seen in gramulomatous disease

Question 23

Vitamin E

Answer 23

Antioxidant (protects RBCs and membranes from free radical damage) — deficiency leads to hemolytic anemia, demyelination, acanthocytosis

Question 24

Vitamin K

Answer 24

Cofactor for y-carboxylation of glutamic acid residues – factors II, VII, IX, X, protein C and S — deficiency leads to neonatal hemorrhage with increased PT and PTT but normal bleeding time, also can occur after prolonged use of antibiotics — not in breast milk so give shot at birth

Question 25

Zinc

Answer 25

Mineral essential for activity of many enzymes --- deficiency leads to delayed wound healing, growth retardation, hypogonadism, decreased hair, anosmia

Question 26

Kwashiorkor

Answer 26

Protein malnutrition leading to skin lesions, edema, liver malfunction --- small child with swollen abdomen

Question 27

Marasmus

Answer 27

Total caloric malnutrition resulting in tissue and muscle wasting, loss of subq fat, and edema

Question 28

Ethanol metabolism

Answer 28

Ethanol to acetaldehyde by alcohol dehydrogenase (inhibted by Fomepizole) --> acetaldehyde to acetate by acetaldehyde dehydrogenase (inhibited by disulfram) ---- both steps require NAD (limiting reagent) --- ethanol metabolism increases NADH to NAD ratio causing lactic acidosis (pyruvate to lactate), fasting hypoglycemia (oxaloacetate to malate), hepatosteatosis (dihydroxyacetone phosphate to glycerol 3 phosphate), no gluconeogenesis