Magnesium Flashcards
Where is magnesium found in the body?
How much of it is free?
Majority in skeleton, then soft tissues: usually bound to ligands and molecules
1% extracellular fluid where 0.6% is free
Magnesium acts primarily as
stabilizer and complexer for organic phosphates and nucleic acid
Mg is essential for aerobic and anaerobic metabolism. Which essential functions does this include?
Cellular energy metabolism (lipid and carb)
Nucleic acid and Protein syn
2nd Messenger system
Ion channel (stabilizer)
How does Mg differ from calcium
large hydrated volume which makes it not as flexibly in t’s binding state, though still competitive
- in water will increase “hardness”
How is mg involved in ATP/ADP
Stabilizers the Phosphate tails
Functions of Mg in glycolysis
activate enzyme, involved in energy making / using
makes substrates less available by temp binding
How is Mg involved in Protein syn
bind specifically to the phosphate group on nucleic acids for activity and for stabilization - prevent damage and degradation
Mg as a secondary messenger: Adenylate cyclase
Adenylate cyclase: G-protein bound to activate (w/GTP), to enhance interaction, to drive cAMP link, to provide energy for Kinase A
Mg as a secondary messenger: IP3
Provides substate for PIP2
Inverse relationship b/w [Mg] and IP3 activation
Drives Protein Kinase C step
Mg for ion channels
Needed to pump K out of cells (actively and passively)
ATP synthase
Food sources of Mg
high - legumes, green leafy veg, nuts, unpolished grains
Moderate - meat, fruits, dairy
RDA / AI for Mg
Infants: 30-75 AI
Men: 400-420 mg/d
Women: 310-360 mg/d
- Need more when growing - 14-18
- more when pregnant b/c of wt gain
Absorption of Mg
30-50% absorbed - entire intestine but mainly in ileum and lower J.
More is absorbed when you eat less (inverse relationship - tightly reg)
Proteins + Fiber can decrease absorp
Why would absorption of Mg not be a problem if body gets deficient?
Its a passive and active absorption system
Best absorption: Carbonate, Citrate, Glycinate, Malate
Citrate (18% - 90 bioavail)
Glycinate (18% - 80)
Malate (6.5% - 70)
Carbonate (45% - 30)