Fat soluble vitamins Flashcards
Disease category associated with fat-soluble vitamin deficiency?
fat malabsorption syndomes
why do FSV deficiencies develop only after months of inadequate intake?
FSVs are stored in the body and metabolized slowly
excess of which FSVs leads to toxicity?
A and D
Vitamin A also known as
- retinol
- retinal - essential visual pigment
- retinoic acid - maintains differentiation in epithelial cells
Where do we get vitamin A?
- animal sources
- also derived from B-carotene present in plants
vitamin A deficiency
- causes 1.2 million cases of permanent blindness annually in the developing world
- first symptom is night blindness
- signs of deficiency: xeropthalmia, Bitot’s spots
vitamin A therapeutic use
- used for acne and psoriasis
vitamin A toxicity
- skin rash
- liver damage
- raised intracranial pressure
- teratogenic: do not give to pregnant patients
Where do we get vitamin D?
- produced endogenously in skin by UV radiation
- obtained from either animal or plant tissues
Active form of vitamin D?
calcitriol
importance of calcitriol?
steroid hormone that increases calcium absorption by the intestine epithelium
vitamin D deficiency
- demineralization of formed bone in adults (osteomalacia
- failure to mineralize developing bones in children (rickets)
risk factors for vitamin D deficiency
- lack of milk consumption
- dark skin
- low sun exposure
calcitriol therapeutic use
- given for vitamin D deficiency but often causes hypercalcemia “bones, stones, abdominal moans”
vitamin E also known as
tocopherol
what does tocopherol (E) do?
- antioxidant that protects lipid membranes
tocopherol (E) deficiency
red blood cell fragility
vitamin K physiological significance
- needed for post-translational carboxylation of glutamate, which is required for calcium binding by blood clotting factors
where do our bodies get vitamin K?
produced by intestinal bacteria
vitamin K deficiency
- leads to hemorrhage with a long prothrombin (clotting) time
vitamin K therapeutic use
- administered to premature infants which lack the bacteria that provide vitamin K
- adults on long-term antibiotics
why block vitamin K?
- sometimes intentionally blocked by the drug coumarin to prevent clotting in patients with prosthetic heart valves
