BC Calcium & Vit. D #21.txt

  1. Spinach has the worse calcium bioavailability
    Same reason as with Iron, due to oxalate that bind to the free Ca and Fe and won't release it
  2. What inhibits Ca bioavailability?
    • Phytates (beans)
    • Polyphenols (tea/coffee)
    • Oxalate (Spinach)
  3. When is absorption of Ca increased? (4)
    • 1) low Ca diet
    • 2) Pregnancy
    • 3) Lactation
    • 4) growth
  4. Ca utilizes what kind of absorption?
  5. What type of pH is needed to absorb Ca?
    Low pH
  6. If the pH is high, what will bind and sequester Ca?
    Phosphate to form insoluble calcium phosphate
  7. When Ca is low, what absorption path is used?
  8. Are Paracellular and Transcellular absorption Vit. D dependent/Ind.?
    • Paracellular: independent
    • Transcellular: dependent
  9. What form of Vit. D is necessary for transcellular absorption?
    Calcitriol 1,25 (OH)2D3
  10. Where are TRPV5/6 located and what is their function?
    • TRPV5 = kidney
    • TRPV6 = liver
    • **both absorb Ca for transcellular absorption
    • **transcribed by calcitriol in the nucleus
  11. What binds Ca to keep it unbound from Phosphate?
  12. What are the two basolateral transporters of Ca?
    • Ca-ATPase - primary active transport
    • NA/CX - Secondary active transport
  13. How is Vit. D3 formed and what is it called?
    7-dehydrocholesterol + UV light = Cholecalciferol (Vit. D3)
  14. What contains vit. D2 and what is it called?
    • Found in plants/plankton
    • Ergocalciferol
  15. What are the three forms of vitamin D called?
    • Vitamin D: Calcitriol
    • Vitamin D2: ergocalciferol
    • Vitamin D3: Cholecalciferol
  16. What must general Vitamin D be transformed to in the liver and kidney?
    • Liver: Calcidiol
    • Kidney: Calcitriol
  17. What happens with the PTH with increased vitamin D and increased Ca?
    PTH is inhibited
  18. Where does the PTH work, kidney or liver?
    Kidney to produce Calcitriol
  19. What are the effects of calcitriol in the kidney? (4)
    • Increase intestinal Ca absorption
    • Mobilize Ca from bone
    • increase renal absorption of Ca
    • decrease Renal excretion of Ca
  20. What causes calciuria?
    • Excess NaCl
    • Problem with older women due to loss of estrogen
  21. What can counterbalance the NaCl effect ad Calcuria?
    Potassium Citrate
  22. How does the thyroid gland effect Ca?
    • When Ca is high, the thyroid gland releases calcitriol
    • Calcitriol stops Ca bone mobilization
    • Allows Vit. D to be used in other body systems
  23. What part of the bone is most susceptible to Osteo.?
    Trabecular (center, spongy)
  24. When does Osteopenia become osteoporosis?
    When BMD <-2.5
  25. What happens to Ca and Vit. D levels with aging?
    They both decrease
  26. At what age should we worry about a low BMD?
    30, b/c this is when we should be at our peak BMD
  27. What are the three risk factors for osteoporesis?
    • 1) Age
    • 2) BMD level low at age 30
    • 3) Menopause
  28. What should you supplement with if you suffer from osteoporosis?
    Vitamin D + Calcium
  29. Why is exercise important to inhibit osteoporosis?
    It increases bone density
Card Set
BC Calcium & Vit. D #21.txt
BC Calcium & Vit. D