Exam 3 Notes

Exam 3 Notes - NFS 441 Exam 3 Ch. 9 Water Soluble Vitamins:...

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NFS 441 Exam 3 Ch. 9 Water Soluble Vitamins: FOLATE: SOURCES: -Mushrooms -Green vegetables -Peanuts -Legumes -Lentils -Fruits -Liver DIGESTION & ABSORPTION: -Polyglutamate forms hydrolyzed to monoglutamate form -Reduced to THF in enterocytes, then methylated to 5-methyl THF or formylated -Transported in portal circulation as 5-methyl THF -Found as a monoglutamate in blood FUNCTIONS OF ACTION: -Amino Acid Metabolism -Histidine -Serine & glycine -Methionine NUCLEOTIDE METABOLISM: INTERACTIONS W/ OTHER NUTRIENTS: -Vitamin B12 RDA: -ADULTS = 400ug (Folate Equivalents) -PREGNANCY = 600ug DFE -LACTATION = 500ug DFE DEFICIENCY: -Megaloblastic Macrocytic Anemia TOXICITY: -UL = 1mg synthetic (non-natural) ASSESSMENT OF NUTRITURE: -Plasma, Serum or RBC conc.
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VITAMIN B12 (COBALAMIN): SOURCES: -Animal Products (STOMACH) -Released from proteins/polypeptides -Binds to an R protein (temporary transit protein) GROUP ATTACHED: -CN = Cyanocobalamin -OH = Hydroxocobalamin -H20 = Aquocobalamin -NO2 = Nitritocobaamin -5’-deoxyadenosyl = 5’-deoxyadenosylcobalamin -CH3 = Methylcobalamin DUODENUM: -R protein hydrolyzed-Free cobalamin -Binds to intrinsic factor ILEUM: -Absorbed via binding with receptors (cubilins) -Binds to transcobalamin II for transport -Enterohepatic circulation BLOOD: -In blood, bound to 1 of 3 transport proteins -Can be stored and retained in the body for long periods FUNCTIONS OF ACTION: -Conversion of homocysteine to methionine (methylcobalamin) -Conversion of L-methylmaonyl CoA to succinyl CoA (adenosylcobalamin) METABOLISM & EXCRETION: -0.1% per day excreted in bile, bound to R protein RDA: -ADULTS = 2.4ug -PREGNANCY = 2.6ug -LACTATION = 2.8ug DEFICIENCY: -Megaloblastic macrocytic anemia -Also neuropathy -Usually caused by inadequate absorption
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-Yellow skin pallor TOXICITY: -None observed ASSESSMENT OF NUTRITURE: -Serum conc. -Serum methylmalonyl CoA or methylmalonic acid homocysteine VITAMIN B6: SOURCES: -Meats -Whole Grains -Vegetables -Some Fruits -Nuts ABSORPTION: -Phosphorylated to PN, PL, or PM -PN, PL & PM released into portal blood -Most converted to PLP in liver -Most PLP transported bound to albumin FUNCTIONS OF ACTION: COENZYMES: -Transamination: Takes an amino group and an alpha keto to an amino acid group -Decarboxylation -Transulfhydration & desulhydration -Dehydration (also called elimination) or deamnation -Cleavage -Racemization -Other synthetic reactions -Glycogen degradation NONCOENZYME ROLE: -Steroid hormone action RDA: -MEN 19-50 = 1.3mg -MEN 51 & Over = 1.7mg -WOMEN 19-50 = 1.3 mg -WOMEN 51 & Over = 1.5mg -PREGNANCY = 1.9mg -LACTATION = 2.0mg
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DEFICIENCY: -Rare, but more likely in elderly, alcoholics, people on certain drugs (corticosteroids, anticonvulsants) TOXICITY: -Sensory and peripheral neuropathy -UL = 100mg- Blocks neurological transmission -Scaling Dermatosis: Scaly skin ASSESSMENT OF NUTRITURE: -Plasma PLP concentrations -Xanthurenic acid excretion following tryptophan loading
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This note was uploaded on 12/22/2009 for the course NFS 441 taught by Professor Gerber during the Spring '09 term at Rhode Island.

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Exam 3 Notes - NFS 441 Exam 3 Ch. 9 Water Soluble Vitamins:...

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