Vitamins Flashcards
Retinol
Vitamin A
Thiamine
B1
Niacin
B3
Biotin
B7
Riboflavin
B2
Pantothenate
B5
TPP
B1
NAD+ and NADP+
B3
FAD and FMN
B2
CoA
B5
Pyridoxine
B6
Ascorbic acid
C
Cobalamin
B12
Folic Aid
B9
Tocopherol/tocotrienol
E
What is the function of Vitamin A?
- Antioxidant
- Constituent of visual pigments
- Treats measles and AML
- Needed for differentiation of epithelial cells
What can Vitamin A deficiency cause?
- Night blindness (nyctalopia)
- Dry, scaly skin (xerosis cutis)
- Alopecia
- Corneal degeneration (keratomalacia)
- Immune suppression
What can Vitamin A excess cause?
- Pseudotumor cerebri (Elevated ICP)
- Teratogenic, cleft palate and cardiac anomalies
- Arthralgias
What enzymes require B1 as a cofactor?
- Alpha-ketoglutarate dehydrogenase (TCA)
- Transketolase (HMP)
- Pyruvate dehydrogenase (TCA)
What results from a B1 deficiency?
Impaired glucose breakdown and ATP depletion, especially in the brain and heart
What is deficient in Wet beriberi and how does it present?
- Deficiency = Vitamin B1
- Presentation = High output cardiac failure, dilated cardiomyopathy and edema
What is deficient in Dry beriberi and how does it present?
- Deficiency = Vitamin B1
- Presentation = Polyneuritis, symmetrical muscle wasting (toe, wrist or foot drop)
What is deficient in Wernicke-Korsakoff syndrome and how does it present?
- Deficiency = Vitamin B1
- Presentation = Confusion + Opthalmoplegia + Ataxia + Confabulation, medial dorsal thalamic nucleus damaged
From what amino acid is B3 synthesized and what cofactors does this process require?
Tryptophan, B2+B6
What are the functions of vitamin B3?
- Redox reactions (NAD+ carries H+ producing 3 ATP)
2. Treat dyslipidemia (decreases VLDL and increases HDL)
How does niacin deficiency present?
Glossitis if minor
Pellagra if severe: Dementia, Diarrhea and Dermatitis
What vitamin deficiency can be caused by Hartnup disease?
Niacin
What vitamin deficiency can malignant carcinoid syndrome cause, how?
Niacin, increased tryptophan metabolism
What vitamin deficiency can Isoniazid cause, how?
Niacin, due to decrease in B6
How does niacin excess present?
Flushing (due to prostaglandin) + Hyperglycemia + Hyperuricemia
What is the active form of B6? What is it used for?
Pyridoxal phosphate
Used for transamination (AST/ALT), decarboxylation, and glycogen phosphorylation
What compounds require B6 for synthesis?
- Cystathionine
- Heme
- Niacin
- Histmine
- Serotonin
- Epinephrine
- NE
- DA
- GABA
How does B6 deficiency present?
Convulsions, hyperirritability and peripheral neuropathy
What drugs can induce B6 deficiency?
Isoniazid and oral contraceptives
What enzymes require biotin?
Carboxylation enzymes
- Pyruvate carboxylase
- Acetyl-CoA carboxylase
- Propionyl-CoA carboxylase
What vitamin deficiency can excessive raw egg consumption cause? How?
B7, avidin (a protein in the egg whites) binds up the biotin and prevents its absorption
What is the function of folate?
Used as THF as a cofactor for 1 carbon transfer reactions, especiallyin the synthesis of bases for DNA and RNA
Where is folate found and how is it absorbed?
Found in green leafy vegetables, absorbed in the jejunum and a small reserve is stored in the liver
How does B9 deficiency present?
Macrocytic, megaloblastic anemia with hypersegmented PMNs and glossitis
What will labs indicate in B9 deficiency?
Increased homocysteine with normal methylmalonic acid
What is the most common vitamin deficiency in the United States?
Folate deficiency
What is the function of B12?
Cofactor for homocysteine methyltransferase and methylmalonyl-CoA mutase
Where does cobalamin come from?
Found in animal products, only synthesized by microorganisms. We have a large reserve (years worth) stored in the liver
How does B12 deficiency present?
Macrocytic, megaloblastic anemia with hypersegmented PMNs, paresthesias and degeneration of the dorsal columns and the lateral corticospianal tracts
What lab findings are associated with B12 deficiency?
Increased homocysteine and increased methylmalonic acid levels
What are the most common causes of B12 deficiency?
Insufficient intake, malabsorption, lack of intrinsic factor, and absence of terminal ileum
What are the functions of vitamin C?
- Antioxidant
- Necessary for the hydroxylation of proline and lysine in collagen synthesis
- Needed for dopamine-Beta-hydroxylase (DA->NE)
What does a vitamin C deficiency present as?
Scurvy: Swollen gums, bruising, hemarthrosis, anemia, poor wound healing (due to collagen synthesis defect)
What is the function of vitamin D?
- Increase intestinal absorption of calcium and phosphate
2. Increased bone mineralization
What does vitamin D deficiency cause?
- Rickets or Osteomalacia
- Hypocalcemic tetany
- Breastfed infants needs oral vitamin D
What is the function of vitamin E?
Antioxidant protecting erythrocyte membranes?
What does vitamin E deficiency cause?
Hemolytic anemia and ataxia (from demyelination)
What is the function of vitamin K?
-Cofactor for gamma carboxylation of glutamic acid residues of clotting factors (2,7,9,10 C and S)
What does a deficiency of vitamin K cause?
-Neonatal hemorrhage with increased PT and PTT
Because gut has no flora to synthesize the K for them
