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.
Kwashiorkor
Protein malnutrition –> skin lesions, edema (v plasma oncotic pressure), liver malfunction (v apolipoprotein synthesis –> fatty change).
Small child w swollen abdomen.
MEAL: Malnutrition, Edema, Anemia, Liver (fatty).
Marasmus
Total calorie malnutrition –> emaciation (tissue and muscle wasting, loss of subcutaneous fat).
+/- edema.
