NFS382H1 Lecture Notes - Lecture 9: Bone Density, Calcium Citrate, Bone Mineral
Document Summary
Calcium is the most abundant divalent ion in the body. Within the fluids of the body, calcium is found in the ionic form (ca2+) Dri: ul is quite close to the rda, for infants, it is ai (based on breast milk) Sources: milk, soy milk, tofu, kale, orange juice, poor sources: meats, grains, and nuts. Absorption: has to be solubilized by acid in the stomach to allow absorption, solubility does not necessarily mean better absorption free to bind to other things, primarily duodenum, proximal jejunum (90%) Saturable, carrier mediated active transport requiring energy. Non-saturable, paracellular (between enterocytes), vitamin d dependent. Factors influencing absorption: amount of ca consumed (i. e. increased absorption <400mg, requirements (i. e. pregnancy and infancy) Individuals on proton pump inhibitors results in insufficient production of gastric acids. Slide 13: figure of calcium absorption: calcium crosses the brush border membrane using trpv6, can also take other divalent cations. Intracellular calcium concentration regulation exchange and proton pump.
