Nutrition Flashcards
Vitamin A functions
Retinol - antioxidant, visual pigments, normal differentiation of epithelial cells into specialized tissue (pancreatic, respiratory/urinary tracts, occular conjunctiva - prevents metaplasia), TREATS MEASLES and AML
Vitamin A deficiency
Night blindness, dry/scaly skin, corneal degneration, immunosuppression
Vitamin A excess
Acute (nausea, vomiting, blurred vision) – chronic (alopecia, dry skin, hepatic toxicity, arthralgias, papilledema) – TERATOGENIC! (cleft palate, cardiac abnormalities, microcephaly)
Vitamin B1 functions
Thiamine - TPP is cofactor for Pyruvate dehydrogenase, a-ketoglutarate dehydrogenase, transketolase, and branched chain ketoacid dehydrogenase
Vitamin B1 deficiency
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
Vitamin B2
Riboflavin – makes up FAD and FMN (cofactors) —- deficiency causes cheilosis (inflammation of lips, scaling at corners of mouth), corneal vascularization, dermatitis, and stomatitis
Vitamin B3 functions
Niacin - makes up NAD (redox reactions) — made from trytophan (requires vitamin B2 and B6 to make), lowers levels of VLDL and raises HDL
Vitamin B3 deficiency
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)
Vitamin B3 excess
Facial flushing (d/t prostaglandins), hyperglycemia, hyperuricemia
Vitamin B5
Pantothenic acid – part of coenzyme A and fatty acid synthase — deficiency causes alopecia, adrenal insufficiency
Vitamin B6
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
Vitamin B7
Biotin - cofactor for carboxylation enzmyes (pyruvate carboxylase, acetal-coa carboxylase, propionyl coa carboylase) — deficiency is rare and caused by raw egg whites
Vitamin B9 functions
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
Vitamin B9 deficiency
Macrocytic, megaloblastic anemia, hypersegmented PMNs, glossitis – increased homocysteine but normal methylmalonic acid — seen in alcoholism and pregnancy – MC vitamin deficiency in US
Vitamin B12 functions
Cobalamin - Cofactor for homocystine methyltranferase and methylmalonyl-coa mutase — hepatic stores for years