Vitamin

  1. Water soluble vitamine
    The Real News for Political Pundits and Criminals
    • B1 (thiamine:TPP)
    • B2 (riboflavin: FAD, FMN)
    • B3 (niacin:NAD+)
    • B5 (Pantothenic acid: CoA)
    • B6 (pyridoxine: PLP)
    • B12 (cobalamin)
    • Biotin
    • C (ascorbic acid)

    B12 and folate are the only two stored in liver

    B-complex deficiencies often result in dermatitis, glossitis, and diarrhea
  2. Vitamin A (retinol)
    • 1. antioxidant
    • 2. constituent of visual pigments (retinal)
    • 3. essential for normal differentiation of epithelial cells into specialized tissue (pancreatic cells, mucus-secreting cells)
    • 4. prevents squamous metaplasia
    • 5. used to treat measles and AML, subtype M3; wrinkles and acne
    • 6. found in liver and leafy vegetables

    Deficiency: Night blindness, dry skin

    Excess: Arthralgias, fatigue, headaches, skin changes, sore throat, alopecia. Tertogenic (cleft palate, cardiac abnormalities), so a pregnancy test must be done before isotretinoin is prescribed for severe acne
  3. Vitamin B1 (thiamine)
    Thiamine pyrophosphate (TPP)
    Ber1 Ber1
    Wernicke- Korsakoff (triad)
    • Decarboxylation reactions:
    • 1. pyruvate dehydrogenase
    • 2. alpha-ketoglutarate dehydrogenase (TCA cycle)
    • 3. Transketolase (HMP shunt)
    • 4. Branched-chain AA dehydrogenase

    • Deficiency: impaired glucose breakdown; brain and heart affected first;
    • Triad: confusion, ophthalmoplegia, ataxia + confabulation, personality change, memory loss (permanent). Damage to medial dorsal nucleus of thalamus, mammillary bodies
    • Dry beriberi- polyneuritis, symmetrical muscle wasting
    • Wet beriberi- high-output cardiac failure (dilated cardiomyopathy), edema
  4. Vitamin B2 (riboflavin)
    B2= 2ATP
    cofactor in oxidation and reduction (FADH2)

    Deficiency: Cheilosis (inflammation of lips, scaling and fissures at the corners of the mouth), Corneal vascularization
  5. Vitamin B3 (niacin)
    B3= 3 ATP
    3 D's= diarrhea, dermatitis, dementia
    • Constituent of NAD+, NADP+
    • Derived from tryptophan
    • synthesis requires B6

    Deficiency: Glossitis. Severe deficiency leads to pellagra: caused by Hartnup disease (dec tryptophan absorption), malignant carcinoid syndrome (inc tryptophan metabolism), and INH (dec vit B6)

    Excess: Facial flushing (due to pharmacologic doses for treatment of hyperlipidemia)
  6. Vitamin B5 (pantothenate)
    Essential component of CoA (a cofactor for acyl transfers) and fatty acid synthase

    Deficiency: dermatitis, enteritis, alopecia, adrenal insufficiency
  7. Vitamin B6 (pyridoxine)
    converted to pyridoxal phosphate, a cofactor used in transamination decarboxylation reaction, glycogen phosphorylase. Synthesis of cystathionine, heme, niacin and GABA

    Deficiency: convulsions, hyperirritability, peripheral neuropathy (deficiency inducible by INH and oral contraceptives), sideroblastic anemias due to impaired Hb synthesis and Fe excess
  8. Vitamin B12 (cobalamin)
    cofactor for homocysteine methyltransferase and methylmalonyl-CoA mutase (Odd #C fatty acids)

    Deficiency: Macrocytic, megaloblastic anemia, hypersegmented PMNs, neurologic symptoms (paresthesias, subacute combined degeneration) due to abnormal myelin. Prolonged deficiency leads to irreversible nervous system damage

    • Found in animal products
    • synthesized only by microorganisms.
    • Deficiency is usually caused by malabsorption (sprue, enteritis, Diphyllobothrium latum), lack of intrinsic factor (pernicious anemia, gastric bypass surgery), or absence of terminal ileum (Crohn's disease)
    • Use Schilling test to detect the etiology of the deficiency.
  9. Folic Acid
    • Converted to tetrahydrofolate (THF)
    • important for the synthesis of nitrogenous bases in DNA and RNA

    Deficiency: most common seen in alcoholism and pregnancy; macrocytic, megaloblastic anemia. caused by several drugs (eg phenytoin, sulfonamides, MTX)
  10. S-adenosyl-methionine (SAM)
    • ATP + methionine --> SAM
    • transfers methyl units- required fro the conversion of NE to epinephrine
    • regeneration of methionine (thus SAM) is dependent on vitamin B12 and folate
  11. Biotin
    • cofactor for carboxylation enzymes
    • 1. pyruvate carboxylase: pyruvate (3 C) --> oxaloacetate
    • 2. Acetyl-CoA carboxylase: acetyl-CoA (2 C)--> malonyl-CoA
    • 3. Propionyl-CoA Carboxylase: propionyl-CoA (3C) --> methylmalonyl-CoA

    Deficiency: Rare caused by antibiotic (biotin synthesized by GI bacteria) use or excessive ingestion of raw eggs (egg whites). Dermatitis, alopecia, enteritis
  12. Vitamin C (ascorbic acid)
    Found in fruits and vegetables

    • 1. facilitates iron absorption by keeping iron in Fe2+ reduced state
    • 2. necessary for hydroxylation of proline and lysine in collagen synthesis
    • 3. necessary for dopamine b-hydroxylase, which coverts dopamine to NE

    Deficiency: scurvy- swollen gums, bruising, hemarthrosis, anemia, poor wound healing; weakened immune response.

    Excess: nausea, vomiting, diarrhea, fatigue, sleep problems. Can inc risk of iron toxicity in predisposed individuals (transfusions, hereditary hemochromatosis)
  13. Vitamin D
    • 7 alpha-dehydrocholesterol in skin
    • D2= ergocalciferol- ingested from plants
    • D3= cholecalciferol- consumed in milk, formed in sun-exposed skin
    • 25-OH D3= storage form
    • 1,25 (OH)2 D3 (calcitriol)= active form

    Deficiency: hyopcalcemic tetany, breast milk has dec vit D

    Excess: loss of appetite, stupor, seen in sarcoidosis (inc activation of vit D by epithelioid macrophages)
  14. Vitamin E
    Antioxidant (protects erythrocytes and membranes from free-radical damage)

    Deficiency: inc fragility of erythrocytes (hemolytic anemia), muscle weakness (necrotizing myopathy), posterior column and spinocerebellar tract demyelination (similar to B12 deficiency)
  15. Vitamin K
    • catalyzes gamma-carboxylation of glutamic acid (II, VII, IX, X, protein C and S)
    • synthesized by intestinal flora
    • also activate osteocalcin (inhibits calcification of arteries & cartilage)

    Deficiency: neonatal hemorrhages w/ inc PT and inc PTT but normal bleeding time (neonates have sterile intestine and are unable to synthesize vit K). Chondrodysplasia punctate: leads to aberrant calcification (early or excessive)
  16. Zinc
    essential for the activity of 100+ enzymes. Imp in the formation of zinc fingers (transcription factor motif)

    Deficiency: delayed wound healing, hypogonadism, dec adullt hair (axillary, facial, pubic), dysgeusia (no taste buds), anosmia (inability to perceive odor). May predispose to alcoholic cirrhosis
Author
manjinder
ID
138177
Card Set
Vitamin
Description
Vitamin
Updated