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Vitamins Vitamins • • • • Essential organic compounds Micronutrients Involved in growth, metabolism, healing/health, immunity Vitamins • Water-soluble or fat-soluble • Dietary reference intakes (DRI) • Deficiency associated with malnutrition, malabsorption from chronic disorders or genetically inherited diseases • Toxicity from Vitamin A & D Vitamin A Source • Carotenoids from plants, green & yellow vegetables, yellow fruits • liver, fish liver oils • dairy fat • egg yolk Forms • all-trans-retinol: alcohol form • Pro-Vitamin A carotenoids (-,-,carotenes) • Retinyl palmitate: storage form • Retinal: aldehyde form • Retinoic acid Vitamin A Forms and Function • Retinoic Acid most important vit A metabolite • Acts as a ligand for specific nuclear transcription factors • Retinoic acid gene receptors vital in fundamental biological activities of all cells: division, death, differentiation • Retinal: rhodopsin in rods of the retina Vitamin A deficiency • Night- blindness, photophobia: absence of retinal in rhodopsin of the retina • Xerophthalmia keratomalacia • Bitot’s spots • conjunctival xerosis At risk for Vitamin A deficiency • Undernourished of mother & child • Measles Tx of Vitamin A deficiency Oral dose to be given on Day 1, 2 & 2 wks later • for age >12 months 200,000 IU • for age 6-12 months 100,000 IU • for age 0-5 months 50,000 IU (unless there is definite evidence that a dose has been given in the last month) Tx of Xerophthalmia • Vitamin A 5000 IU/kg BW OD PO x 5days followed by 25000 IU IM in oil until recovery Prevention of Vitamin A deficiency in High Risk Areas Vitamin A for Mother Vitamin A for Newborn • 200,000 IU OD x 2 doses post-partum • 25,000 IU x 3 doses at 1-3 months of age Hypervitaminosis A • Excess over weeks or months • Adults 50000 IU Child 20000 IU • Sx: headache, vomiting, anorexia, seborrhea, oral fissures, alopecia, bone abnormalities: hyperostosis, hepatosplenomegaly, diplopia, irritability, stupor • Sx resolve on withdrawal of Vit A Hypervitaminosis A • Congenital malformations & abortions: 0.5-1.5mg/kg oral retinoic acid for acne or cancer, >20% incidence • Carotenemia: yellow discoloration of skin due to excessive intake of carotenoids (low enzymes, liver dse, DM or hypothyroidism) Vitamin B Complex • • • • • • • • • • Thiamine Riboflavin Niacin Vitamin B6 Folate Vitamin B12 Biotin Pantothenic Acid (Choline) (Inositol) Thiamine (Vitamin B1) Source • meat (lean pork) • legumes • cereal Forms/ functions • Coenzyme thiamine pyrophosphate (glycolysis) • Hexose monophosphate shunt • Synthesis of acetylcholine (nerve conduction) Prevention of Thiamine deficiency • Undernourishment of mother & child • Diseases of the gastrointestinal tract and liver • Increased requirement if CHO in diet is high: TPN, Alcoholics • Thiamine dependence: megaloblastic anemia, maple syrup urine disease, Leigh encephalomyelopathy Clinical Manifestation of Thiamine deficiency • Fatigue, apathy, irritability, depression, poor concentration, anorexia, nausea, abdominal discomfort • Peripheral neuritis (paresthesias of the toes and feet), DTR’s, loss of vibration sense, leg cramps, psychic disturbances, ptosis, atrophy of optic nerve • Hoarseness, aphonia Clinical Manifestation of Thiamine deficiency • Muscle atrophy, tenderness of nerve trunks, loss of deep sensation • ICP, meningismus, coma • Wernicke encephalopathy: encephalopathy, opthalmoplegia + ataxia • CHF death Beriberi • • • • • • Wet Undernourished, pale, edema Dyspnea Vomiting Tachycardia Waxy skin Urine albumin, casts Dry • • • • • • • Plump Pale Flabby Listless Dyspnea Tachycardia Hepatomegaly Treatment of Thiamine deficiency • • • • • Vitamin B1 10mg OD PO (child) Vitamin B1 50 mg OD PO (adult) If with CHF, give IV or IM Tx over several weeks Clinical response to thiamine is best confirmation of thiamine deficiency Niacin Source • Meat • Fish poultry • Legumes • Fortified bread and cereal • Tryptophan from milk & eggs (6mg= 1mg niacin) Forms/ functions • Nicotinamide, nicotinic acid & derivatives • Coenzyme NADP, NAD (electron transfer and glycolysis) At risk for Niacin deficiency • Inadequate intake • Regions where corn is a staple Clinical Manifestations of Niacin deficiency • • • • • • • Anorexia Lassitude Weakness Burning sensation Numbness Dizziness Glossitis, GI symptoms, symmetric dermatitis Pellagra • Triad: dermatitis, diarrhea and dementia • Dermatitis symmetric, sharply demarcated from surrounding healthy skin, sun-exposed areas • Scaling, crusting, vesicles, bullae • Pellagrous glove, boot, Casal necklace • Alternating diarrhea and constipation • Depression, disorientation, insomnia, delirium Treatment of Niacin deficiency • Niacin 50-300mg/ day • Niacin 100mg IV, if sever or poor intestinal absorption Vitamin B6 (Pyridoxine) Source • Meat • Fish • Poultry • liver • Fortified Cereal Forms/ functions • • • • Pyrodixine pyridoxal Pyridoxamine Coenzymes Pyridoxal 5phosphate, pyridoxamine phosphate: AA metab, aminotransferases, decarboxylases, racemaces, dehydratases • Neurotransmitter synthesis: serotonin, GABA, dopamine • Synthesis of histamine, heme, porphyrins Functions of Pyridoxine • • • • Metabolism of glycogen Conversion of tryptophan to Niacin Synthesis of cysteine from methionine AA active transport across cell membranes • Chelation of metals • linoleic acid arachidonic acid • linolenic acid docosahexaenoic acid At risk for Pyridoxine deficiency • Inadequate intake • Milling of rice, cereal removes Pyridoxine • Vegetarian • Larger requirement if high protein in diet • Inhibited by drugs: Isoniazid,penicillamine, steroids, anticonvulsants, • Women on oral contraceptives • Maintenance dialysis Clinical Manifestation of Pyridoxine deficiency • • • • • • • • • Irritability & Convulsions in infants Peripheral neuritis Dermatitis anemia Aggravated startle response Cheilosis Glossitis Seborrheic dermatitis infections Vitamin B6 dependence Syndromes • • • • • Vit B6- dependent convulsions Vit B6- responsive anemia Xanthurenic aciduria Cystathioninuria homocystinuria Treatment of Pyridoxine deficiency • Vitamin B6 100mg IM for Infantile seizures • Daily Vitamin B6 2-10mg IM or 10100mg PO if pyridoxine-dependent Folate Source • Green vegetables • Oranges • Legumes, nuts • Fortified Cereal • liver • yeast Forms/ functions • Folic acid= pteroylglutamic acid • Folate coenzymes: DNA and purine synthesis, AA intercorversion, homocysteine methionine Prevention of Folate Deficiency • Inadequate intake • Deficiency during periods of rapid growth or increased cellular metabolism • (sickle cell anemia), psoriasis • NSAIDs, anticonvulsants i.e. diphenylhydantoin, phenobarbital, Methotrexate • Pregnancy,Protective for neural tube defects (spina bifida, anencephaly) Prevention of Folate Deficiency • Malabsorption (hereditary folate malabsorption, celiac, inflammatory bowel disease, alcoholism) • Inborn errors of folate metabolism • Autoantibodies against cerebral folate receptor in the choroid plexus Hereditary Folate Malabsorption • Recurrent diarrhea, failure to thrive, oral ulcers, neurologic deterioration, megaloblastic anemia • At 1-3 months of age • Poor neurologic outcome • poor immunity • DX: low serum folate • Rx: Folinic acid IM or hi dose oral folinic acid Cerebral Folate Deficiency • Irritability, microcephaly, developmental delay, cerebellar ataxia, pyramidal tract signschoreoathetosis, ballismus, seizures • Blindness from optic nerve atrophy • Dx: normal serum folate, low CSF folate • Rx: oral folinic acid Treatment of Folate Deficiency • Women of child-bearing age: Folate 400mcg daily Vitamin B12 (Cobalamin) Source • Muscle meats • Eggs • Dairy • Tempeh, nori • Fortified cereal Functions of Vitamin B12 (Cobalamin) Forms/ functions • Cofactor for lipid and carbohydrate metabolism • Isomerization of methylmalonyl coenzyme A to succinyl coenzyme A • Maintainance of cellular folate levels; Folate metabolism; homocysteine methionine • Protein biosynthesis • Synthesis of purines and pyramides • Methylation reactions Prevention of Vitamin B12 deficiency • Inadequate intake i.e. strict vegetarian diet in a nursing Mom • Abnormal absorption (gastric resection, autoimmune pernicious anemia with IF deficiency) • Poor ileal absorption (Crohn’s, tropical sprue, SBS) • Competition for B12 in the gut • IEM of Vit B12 Transcobalamin II deficiency • Inherited defect • Defective intestinal transport of Vitamin B12 • Severe megaloblastic anemia, Diarrhea, vomiting Juvenile pernicious anemia • Defective IF production in the stomach • Vit B12 malabsorption • Megaloblastic anemia, growth failure Imerslund Syndrome • Defective ileal absorption of Vit B12 • Normal ileal structure and function • Megaloblastic anemia Treatment of Cobalamin deficiency • Vit B12 100mcg once a month IM • Vit B12 1000 mcg twice a week IM for transcobalamin II deficiency • Once in hematologic remission, intranasal Vit B12 500mcg once weekly • If at risk for Leber Optic atrophy, treat with Vit B12 other than cyanocobalamin Vitamin C Source • Vegetables • Fruits esp citrus Forms • Dehydroascorbate: Simple diffusion or Active transport • Ascorbate: plasma transport form Vitamin C functions • Collagen formation: hydroxylation of lysine and proline • Maintains iron and copper in a reduced state for metalloenzymes to convert Dopamine norepinephrine Tryptophan serotonin Cholesterol steroids • Antioxidant • Enhances non-heme iron absorption, transfer of iron from transferrin to ferritin & formation of tetrahydrofolic acid Clinical Manifestation of Vitamin C deficiency • • • • • • • • • Onset of Sx 6-24 months of age Fever Irritability Tachypnea Digestive disturbances Loss of appetite Generalized tenderness (pseudoparalysis) Leg edema Femoral subperiosteal hemorrhage Clinical Manifestation of Vitamin C deficiency • • • • • Scorbutic rosary Sternal depression Gingival swellings Anemia Sicca syndrome of Sjögren: xerostomia, keratoconjunctivitis sicca, enlarged salivary glands • Swollen joints, arthralgia, muscle weakness • Purpura, ecchymosis, petecchiae, perifollicular hemorrhages • Hyperkeratosis of hair follicles Prevention of Vitamin C deficiency • Cow’s milk, evaporated milk for infants • Picky eaters • Increased requirement: febrile illness, infections, diarrhea Treatment of Vitamin C deficiency • 3-4 oz of orange or tomato juice daily • Vit C 100-200mg oral or IV daily • Rapid recovery of sx and resumption of normal growth • Resolution of swelling from subperiosteal hemorrhage after several months Vitamin D Source • Exposure to sunlight • Fish oils • Fatty fish • Egg yolks • Fortified formula, milk, cereal, bread Forms/ functions • Skin: 7dehydrocholesterol Vitamin D3 • Liver: Vit D 25hydroxy vit D (25-D) • Kidney: 25-D 1,25Dihydroxyvitamin D Functions of Vitamin D • 1,25-D binds to intracellular receptor gene expression • Increase calcium absorption in the intestines • Inc. in phosphorus absorption • Negative feedback: Inhibits PTH secretion and 1,25-D synthesis • Mediates bone resorption Clinical Manifestation of Vitamin D deficiency • Rickets in growing children • Osteomalacia • Tetany and seizures from hypocalcemia Rickets • A disease of growing bones skeletal deformities, short stature • Craniotabes: softening of cranial bones • Growth plate widening swelling of wrists and ankles, Rachitic rosary • Softening of the ribs Harrison’s groove • Failure to thrive • Symptomatic hypocalcemia Rickets on Xray • Wrist PA: rachitic changes • Loss of sharp/convex border at the end of the metaphysis: fraying, cupping • Thickening of the growth plate: decreased calcification Prevention of Vitamin D deficiency • Inadequate intake • Inadequate cutaneous synthesis • Breastfed baby must get sunlight or 200-400 IU Vitamin D po • Drugs: phenobarbital, phenytoin, INH, RIfampicin • Congenital rickets • Genetic Genetic causes of Rickets • Vitamin D-dependent rickets type 1; Rx: Calcitriol 0.25-0.5mcg/day • Vitamin D-dependent rickets type 2 Treatment of Vitamin D deficiency • Vit D + adequate Calcium and Phosphorus in diet • Stoss therapy: 300,000- 600,000 IU po or IM divided into 2-4 doses in one day • Vitamin D 2000-5000 IU OD po over 4-6 wks • Calcitriol 0.05 mcg/kg/day • Symptomatic hypocalcemia Ca gluconate 100mg/kg bolus or 20mg/kg Calcium Chloride Vitamin E Source • Vegetable oils • Seeds • Nuts • Green leafy vegetables • margarine Forms/ functions • - tocopherol • Anti-oxidant Vitamin E • Antioxidant • Integral part of cell membranes • Prevents lipid peroxidation & freeradical formation Clinical Manifestation of Vitamin E deficiency • Premature infants: transfer of Vit E in last trimester; thrombocytosis, edema, hemolysis • Premature formula: low PUFA, low iron, adequate Vit E • Fat-malabsorption: cholestatic liver disease, short bowel syndrome Clinical Manifestation of Vitamin E deficiency • DTR’s Severe progressive neurologic disorder • Cerebellar disease: limb ataxia, truncal ataxia • Posterior column dysfunction • Retinal disease: visual field constriction, blindness Treatment of Vitamin E deficiency • Neonates: 25-50 units daily for 1 week • -tocopheryl polyethylene glycol succinate (TPGS) 20-25 U/kg/day Vitamin K Source • Green leafy vegetables • Liver • Legumes • Plant oils Forms/ functions • Vit K1-phylloquinone • Vit K2-menaquinones • Cofactor for glutamyl carboxylase Functions of Vitamin K • -glutamyl carboxylase: converts glutamate to carbohyglutamate • Factors II (prothrombin), VII, IX & X • Protein C & S deficiency, Protein Z • Bone and vascular biology Who are at risk for Vitamin K deficiency • Inadequate intake • Decreased absorption: bile saltrequiring Vitamin K- deficiency bleeding (VKDB) • Early VKDB: 1-14 days of life; poor placental transfer, inadequate intake, low Vit K in breastmilk, no intestinal synthesis of Vit K2 in sterile gut • Late VDKB: 2-12 wks; brestfed or occult malabsorption (CF, cholestatic liver disease) • VDKB sec to maternal drugs: warfarin, Pb, Phenytoin) Clinical Manifestation of Vitamin K deficiency • Long-term bone health and vascular health • Early VKDB: GI, mucosal, cutaneous bleeding: umbilical stump, circumcision site • Late VKDB: intracranial bleed frequent • Prolonged protime Treatment Vitamin K deficiency • Vit K 1mg IM/ IV • Vit K 2.5-10mg IV/IM, rapid correction in adolescents • FFP for severe coagulopathy with bleeding • Vitamin K 1mg IM to newborn: current practice Vitamin Excess • Hypervitaminosis A • Hypervitaminosis D Hypervitaminosis D • hypercalcemia: emesis, anorexia, pancreatitis, hypertension, arrhythmias, CNC effects, polyuria, nephrolithiasis, renal failure • Accidental overfortification of milk, inadvertent use as cooking oils, misuse of Vit D supplements Hypervitaminosis A • • • • • • • • • • Anorexia Failure to thrive Dry, cracking skin Hepatosplenomegaly Swelling and pain of long bones Bone fragility Increased ICP Alopecia Carotenemia Fetal abnormalities