Vitamins and Deficiencies Flashcards
Fat soluble vitamins
A, D, E, K.
Absorption depends on gut and pancreas.
Toxicity more common bc accumulate in fat.
Deficiency due to malabsorption syndromes w steatorrhea and mineral oil intake.
Water soluble vitamins
B1-12 (no 4, 8, 10, 11), C.
Wash out easily from body except B12 in liver 3-4 years and B9 in liver for 3-4 months.
B deficiencies –> dermatitis, glossitis, diarrhea.
Can be coenzymes or precursors to organic cofactors.
A
Retinol.
Antioxidant; visual pigments; differentiation of epithelial cells into specialized tissue; prevents squamous metaplasia.
Used to tx measles and AML (subtype M3).
Found in liver and leave vegetables.
Deficiency –> night blindness, dry scaly skin, corneal degeneration, Bitot spots on conjunctiva, immunosuppression.
Excess –> acute and chronic toxicity, teratogenic.
B1
Thiamine: TPP cofactor for dehydrogenase enzyme rxns.
Deficiency –> impaired glucose breakdown. Seen in malnutrition and alcoholism.
^ RBC transketolase activity after B1 administration.
Wernicke-Korsadoff syndrome: confusion, ophthalmoplegia, ataxia. Confabulation, personality change, memory loss. Damage to medial dorsal thalamic nucleus and mammillary bodies.
Dry beriberi: polyneuritis, symmetrical muscle wasting.
Wet beriberi: high-output cardiac failure (dilated cardiomyopathy), edema.
B2
Riboflavin: FAD, FMN cofactors in redox rxns (e.g. succinate dehydrogenase of TCA cycle).
Deficiency –> Cheilosis and Corneal vascularization.
(cheilosis = inflammation of lips, scaling and fissures at corners of mouth).
B3
Niacin: NAD+ used in redox rxns.
Derived from tryptophan.
Used to tx dyslipidemias (lowers VLDL and raises HDL).
Deficiency –> glossitis. Pellagra (Diarrhea, Dementia, Dermatitis broad collar rash).
Hartnup disease: auto recessive deficiency of neutral aa (tryptophan) transporters in renal tubular cells and enterocytes –> neutral aminoaciduria and v absorption from gut –> v niacin –> pellagra. Tx: high protein diet and nicotinic acid.
Excess –> facial flushing (due to PGE - give aspirin), hyperglycemia, hyperuricemia.
B5
Pantothenic acid: CoA and FA synthase.
Deficiency –> dermatitis, enteritis, alopecia, adrenal insufficiency.
B6
Pyridoxine: PLP cofactor in transamination decarboxylation rxns, glycogen phosphorylase.
Synthesis of heme, niacin, cystathione, histamine, NTs.
Deficiency –> convulsions, hyper irritability, peripheral neuropathy, sideroblastic anemias.
B7
Biotin cofactor for carboxylation enzymes that add 1-C group.
- Pyruvate carboxylase: pyruvate –> oxaloacetate.
- Acetyl-CoA carboxylase: acetyl-CoA –> malonyl-CoA.
- Propionyl-CoA carboxylase: propionyl-CoA –> methylmalonyl-CoA.
Deficiency rare and cause by antibiotic use or excessive egg whites.
B9
Folate: THF coenzyme for 1-C transfer/methylation rxns.
DNA and RNA synthesis of nitrogenous bases.
Leafy greens. Absorbed in jejunum. Small reserve in liver.
Deficiency –> macrocytic, megaloblastic anemia - hyperhsegmented polymorphonuclear cells, glossitis, NO neuroscience symptoms.
^ homocysteine, normal methylmalonic acid.
Alcoholism, pregnancy, phenytoin, sulfonamides, methotrexate.
Supplemental maternal folic acid in early pregnancy.
B12
Cobalamin cofactor for methionine synthase (homocysteine –> methionine) and methylmalonyl-CoA mutate (methlymalonyl-CoA –> Succinyl-CoA).
Animal products. Synthesized by microorganism. Large reserve pool in liver.
Deficiency –> macrocytic, megaloblastic anemia, hyperhsegmented PMNs, paresthesias, subacute combined degeneration (abnormal myelin - NEURO defects). If prolonged –> irreversible nerve damage.
^ homocysteine, ^ methylmalonic acid.
Deficiency caused by: malabsorption, Diphyllobothrium latum, lack of intrinsic factor (pernicious anemia), absence of terminal ileum, veganism.
C
Ascorbic acid.
Antioxidant; reduced iron to Fe2+ for absorption; hydroxylation of proline and lysine for collagen synthesis; dopamine–> NE conversion.
Fruits and veggies.
Deficiency–> Scurvy: (due to collagen synthesis defect) swollen gums, bruising, petechiae, hemarthrosis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, corkscrew hair.
Excess: nausea, vomiting, diarrhea, fatigue, calcium oxalate nephrolithiasis, ^ risk iron toxicity.
D
D2 = ergocalciferol - from plants. D3 = cholecalciferol - from milk, sun. 25-OH D3 = storage form. 1,25-(OH)2 D3 = cacitriol = active form. ^ intestinal absorption of calcium and phosphate; ^ bone mineralization (low levels); ^ bone reabsorption (high levels).
Deficiency –> Rickets (kids), osteomalacia (adults), hypocalcemia tetany.
Excess –> hypercalcemia, hypercalciuria, loss of appetite, stupor - seen in granulomatous disease.
E
Tocopherol, tocotrienol.
Antioxidant that protects RBCs and membranes from free radicals.
Deficiency –> hemolytic anemia, acanthocytosis, muscle weakness, demyelination of spinal tract. Similar neuroscience presentation as B12 deficiency, but no megaloblastic anemia or ^ methylmalonic acid.
K
Phytomenadione, phylloquinone, phytonadione.
Cofactor for gamma-carboxylation of glutamate for blood clotting.
Synthesized by intestinal flora.
Necessary or factors 2, 7, 9, 10, proteins C and S.
Warfarin = antagonist.
Deficiency –> neonatal hemorrhage w ^ PT and ^ aPTT, but normal bleeding time. Not in breast milk, so given injection at birth to prevent hemorrhagic disease of the newborn. Can also occur after prolonged use of antibiotics.
