Water soluble vitamins Flashcards
Biochemical function of Thiamin
PDH cofactor
Sources of Thiamin
legumes, rice bran, grains
Biochemical function of Riboflavin
Involved in Glycolysis/TCA cycle
Sources of Riboflavin
dairy, eggs, meat
Biochemical function of Niacin
Involved in Glycolysis/TCA cycle
Sources of Niacin
meat/poultry. Tryptophan is a precursor. Corn with alkaline treatment
What is dry Beri-Beri
Thiamin Deficiency- neuropathy, muscle tenderness weakness and atrophy
What is wet Beri-Beri
Thiamin Deficiency- edema, circulatory collapse, congestive heart failure
What is Wernicke-Korsakoff
Thiamin deficiency- confusion, ophthalmoplegia, ataxia, memory loss (complete correction 25%; partial 50%); peripheral neuropathy
Risk for deficiency
Alcoholics
Vomiting (e.g. s/p bariatric surgery (esp 1st 6 mo post-op)
TPN (total parenteral nutrition), w/o thiamin(deficiency occurs w/in 2-3 wk)
Anorexia nervosa
Re-feeding
Endemic in So Asia (maternal & BF infant) – polished rice diet;
What happens with riboflavin deficiency
cheilosis and angular stomatitis
What happens with Niacin deficiency
Pellagra: Diarrhea Dermatitis Dementia Death
Risk for niacin deficiency
Nutritional/dietary restriction
Cornmeal (w/o germ) based diet (esp w/o alkaline/lime treatment)
Food faddism / restriction
Malabsorption syndromes
Alcoholism
Metabolic “shunting” (carcinoid tumor ↑ serotonin tryptophan)
Biochemical function of folic acid
single C transfers-
nucleic acid synthesis
amino acid metabolism
DNA Methylation
Dietary sources of folic acid
“foliage,” deep green veg, orange juice, whole grains
Risk for deficiency of folic acid
Inadequate intake or increased destruction in food
Alcoholics
Pregnancy – globally, high rates deficiency; WHO: routine supplementation, women of reproductive age
Hematopoietic conditions
Drug/nutrient interactions
Symptoms of folic acid deficiency
*Macrocytic anemia
*Hypersegmented neutrophils
*Glossitis, irritability
*Homocysteinemia
Neural tube defects (occurrence/recurrence)
Biochemical function of B12
Reform tetrahydrafolate from methylfolate (synthesis of methionine)
Catabolism of odd chain length fatty acids
Catalyze isomerization of methylmalonyl Co-A succinyl Co-A (lipid & CHO metabolism)
Dietary sources of B12
Animal products
B12 absorption
Cleave vitamin from dietary protein in stomach
Requires Intrinsic Factor from stomach
Cobalamin-IF absorbed in distal ileum
Transport in circulation: Transcobalamin II
Large liver stores
Risk factors for B12 deficiency
Inadequate IF secretion or antibodies to IF
Gastric atrophy/gastrectomy
Ileal resection
Breastfed infant of B12 deficient vegan mother
B12 deficiency symptoms
Macrocytic anemia & hypersegmented neutrophils
Neurologic disturbances: depression, paresthesias, gait disturbances, burning tongue, dizziness
What is the water soluble vitamin you can overdose on?
B6
What is the biochemical function of Vit C
Reversible Antioxidant- Vit E sparing Provides reducing equivalents to enzymes: Reduction of iron absorption Leukocyte function ( [AA] wbc) Co-substrate in hydroxylation: Collagen synthesis: hydroxylation of proline & lysine; cross-links for tropocollagen Hydroxylation of tryptophan serotonin Conversion dopamine norepinephrine
