BIBC 120 Fat Soluble Vitamins

  1. Where are fat-soluble vitamins found?
    contained in lipid components of food or bound to proteins: digestion requires bile activity
  2. How are fat-soluble vitamins absorbed?
    micelles with dietary fatty acids
  3. How are fat-soluble vitamins circulated from small intestines?
    in chylomicrons
  4. Name four fat-soluble vitamins
    Vitamin A, D, K, E
  5. How are vitamin D synthesized?
    require UV light exposure
  6. What is the only fat-soluble vitamin that acts as a coenzyme?
    Vitamin K
  7. Where is vitamin D found?
  8. WHat is the active form of vitamin D?
    1,25-dihydroxyvitamin D
  9. What do active 1,25-dihydroxyvitamin D bind?
    Vitamin D Receptor (VDR)
  10. What does binding of active vitamin D, VDR, and RXR do?
    directly regulates expression of genes involved with bone turnover and metabolism, and calcium absorption
  11. What does vitamin D act as?
  12. What does vitamin D do?
    • controls calcium homeostasis
    • promotes cell differentiation in bone and the small intestine
  13. WHat does a deficiency in vitamin D cause?
    problems with bone calcification and turnover
  14. Which hormone is released when there is a decrease in serum calcium level?
    release of parathyroid hormones (PTH)
  15. What does PTH do?
    Helps convert vitamin D from inactive to active form
  16. What can vitamin D deficiency lead to in children?
  17. What can vitamin D deficiency lead to in adults?
    loss of bone strength due to inadequate mineralization of new bond during bone turnover
  18. What are the symptoms associated with osteomalacia?
    pain and weakness
  19. What can vitamin D deficiency lead to in older individuals?
    osteoporosis - demineralization of skeleton leading to loss of bone density
  20. What are some factors that affect skin UV light absorption?
    • geographical location
    • race/degree of skin pigmentation - darker skin blocks more UV light
    • cultural - time spent outdoors; body covering
  21. What is used as an indicator of vitamin D status?
    levels of serum 25-hydroxy vitamin D
  22. What is the adequate and inadequate level of vitamin D?
    • adequate: > 30ng/ml
    • inadequate: < 15ng/ml
  23. What is a good source of vitamin D?
    cod liver oil
  24. What are the three preformed vitamin A?
    retinol, retinal, retinoic acid
  25. What can retinal be converted to and which conversion is irreversible?
    retinal can be converted to retinol and retinoic acid. Conversion to retinoic acid is irreversible
  26. What is vitamin A intake measured in?
    retinol activity equivalents (RAE)
  27. Best source of vitamin A?
    beef liver
  28. What is provitamin A also known as and what food source has a lot of it?
    • Beta-carotene
    • carrots
  29. What does insufficient retinal lead to?
    slow regeneration of rhodopsin which can lead to night-blindness and bleaching
  30. Retinoic serves as a ligand for which nuclear receptors?
    • cis-RA binds RXR
    • trans-RA binds RAR
  31. What are the symptoms of vitamin A deficiency disorder?
    • blindness
    • immune disfunction - susceptibility to infection
  32. Where is vitamin A deficiency common?
    China, India, Mexico, Argentina
  33. What is golden rice genetically modified to produce?
Card Set
BIBC 120 Fat Soluble Vitamins