Does Calcium Supplementation Prevent Bone Weakening?
In general, no. If you had sufficient vitamin D, vitamin K, vitamin C and magnesium in your system, the amount of calcium in your diet would likely be sufficient to maintain bone strength.
And, more to your question, if you have insufficiencies of one or more the above four factors, adding calcium would not fix the problem. It would be like trying to fix the shortage of engines in a car factory by bring in more transmissions.
The history of higher and higher calcium recommendations by doctors, public-health officials and companies promoting their calcium-fortified orange juice and supplements has run its course. There has been minimal beneficial effect of calcium supplementation on osteopenia and osteoporosis. But more to my point, there HAS been an increase is soft-tissue calcification from such fortification and supplementation.
And from drinking milk.
Bone health depends on ossification, not calcification.
And bone health depends on collagen maturation.
Minerals and protein. The minerals are uncompressible and the protein is unstretchable, the combination of which makes strength. In reinforced concrete bridges and overpasses, the concrete is uncompressible and the steel is unstretchable, to make such structures strong.
The collagen protein in bone requires a few key amino acids in higher-than-normal amounts. Lysine, proline and glycine. And collagen maturation requires vitamin C, bioflavonoids, and traces of iron, copper and silicon.
The mineral in bone requires calcium and magnesium, and a few other trace minerals (strontium, boron, zinc, manganese, etc.). It also requires calcium-handling metabolic support, which includes vitamin D and vitamin K.
All machines, even bio-machines, require all the component pieces of the machine.
Not just calcium.
Calcium supplementation without the other factors promotes soft-tissue calcification, not ossification (calcium bone-building processes).[Source]