Fat Soluble Vitamins Table Flashcards
What is the function of Vitamin K?
Coagulation and carboxylation - cofactor for gamma-glutamyl carboxylase
What is the source of Vitamin K in the diet?
Phylloquinone (leafy, green vegetables), menaquinones (fermentation in the gut, cheese), menadione (animal feed)
What Pathologies are associated with Vitamin K deficiency?
Deficiency is rare. In infants, malabsorption – manifests as a coagulation disorder (increased PTT and bleeding)
What toxicity is associated with Vitamin K?
None described, no TUL
What should you know about coumadin and vitamin K?
Coumadin = Warfarin
Coumadin prevents regeneration of Vit K components
Where is Vitamin K stored?
Cellular membranes
What is the function of Vitamin A?
Prosthetic groups for opsin protein (important for vision); transcription regulator of RAR, RXR, PPAR – differentiation of goblet cells, prevention of keratinization, apoptosis of ca cells, maturation of DCs, recruitment of Ab secreting cells to gut; Carotenes act as antioxidants
What is the source of Vitamin A in the diet?
Retinyl-acyl esters and carotenes found in red, yellow and orange fruits and vegetables
What pathologies are associated with Vitamin A deficiency?
Anorexia, retarted growth, increased infections, alopecia, keratinization of epithelial cells, eye probe (night blindness, xerophthalmia, Bitot’s spots)
What pathologies are associated with Vitamin A toxicity?
Toxicity = Hypervitaminosis A: TUL is 3,000 ug RAE/day – Nausea, vomiting, HA, desquamation of skin, alopecia, ataxia, liver damage, teratogenic
How do you diagnose Vitamin A deficiencies/toxicities?
Relative Dose Response
Where is Vitamin A stored?
Stellate cells in the liver
What is the function of Vitamin D?
Most important: regulate Ca2+ homeostasis (increases Ca2+ uptake from gut, causes mobilization of bone Ca2+)
VDR – increases expression of Ca2+ transport proteins (TRPV6, calbindin, PMCA1b) and alters tight junction permeability (claudin)
What is the source of Vitamin D in the diet?
Food of animal origin (liver, eggs, fatty fish), shitake mushrooms, fortified in diary products - dietary form is cholecalciferol
What pathology is associated with Vitamin D deficiency?
Can be dietary, genetic, or absorption problem - rickets = seizures, growth retardation, failure of bone mineralization (osteomalacia)
What pathology is associated with Vitamin D toxicity?
Most likely vitamin to have toxic effects; TUL is 4,000 IU – effect begin when serum Vit D is greater than 500 ng/mL, leads to calcification of soft tissue, hyperphosphatemia, HTN
What is increased vitamin D associated with?
Reduced levels of colorectal cancer
What can Vitamin D be synthesized from?
Can be synthesized de novo from cholesterol
What is the main circulating form of Vitamin D in the blood?
25-OH D3 = main circulating form in blood, measured (liver)
What is the biologically active form of Vitamin D?
1,25-OH D3 = biologically active (kidney)
What is the Vitamin D precursor? Where is it located?
7-dehydrocholesterol = Vit D precursor from skin
What is the function of Vitamin E?
Cellular oxidative stress defense - in lipid bilayers, IC, and plasma membranes.
Interactions: inhibits vitamin K absorption and metabolism; when oxidized, can be regenerated by ascorbate
Where is Vitamin E found in the diet?
Tocopherols (saturated) and tocotrienols (polyunsaturated) - abundant in plant oils (palm, sunflower, canola), wheat germ
What pathology is associated with Vitamin E deficiency?
Deficiency is rare, except in people with absorption problems (premies, Crohns, Short bowel syndrome) or inherited lipoprotein disorders – myopathy, hemolytic anemia, peripheral neuropathy, ataxia, loss of vibratory sense
What pathology is associated with Vitamin E toxicity?
Not very toxic - TUL is 1,000 mg/d (very high)
What can regenerate Vitamin E?
When oxidized, can be regenerated by ascorbate
What type of Vitamin E does the liver export?
Liver will only export RRR stereoisomer
