calcium

what is calcium’s functions

• 99% bones + teeth

• <1% enzyme activation, muscle contraction, nerve conduction

what is the RDA for calcium

1000 mg/day

what are the food sources of calcium

• dairy and some veg

how much in percentage is calcium absorbed from foods

30-50%

• depends on vitamin d intake

how does calcium exist in the bone

• as a complex with P (colas, meat, processed foods)

  • hydroxyapatite

what is the ratio of Ca : P in hydroxyapatite

2:1

• ideal ratio for intake

what are factors affecting calcium balance

1. phosphorus (unequal ratio ex. 1:4)

2. protein intake

3. precipitating and chelating substances

4. physical activity

how is protein intake a factor affecting calcium balance

• optimal bone health: Ca, P, Pro.

• animal protein contains sulfur AA

• sulfur (acidic) draws Ca from bones as a buffer

what other food sources can act as buffers for sulfur, an acidic compound, instead of calcium

1. milk

2. veg + fruit

how is precipitating and chelating substances a factor affecting calcium balance

precipitating:

• prevents Ca absorp (phylates + oxylates)

chelating:

• enhances calcium absorp (lactose/sugar AA)

how does physical activity affect calcium balance

stimulus for bone building

what are other factors that affect calcium balance

• smoking, alcohol, salt (increase Ca loss from bone)

• veg+fruit

how does veg + fruit act as a buffer for S-AA

• has k-citrate

• helps decrease Ca loss from bones

what is the calcium deficiency called

osteoporosis

• starts in adolescence but experienced when older

what age do individuals read 90% of bone mass density

20 years old