gastric acid secretion with the food people eat calcium carbonate

Is now available in the market mostly calcium carbonate and calcium citrate form, there are other forms of .
Of calcium such as calcium lactate, Ethyl lactate,  calcium phosphate. In these different calcium, calcium carbonate relatively.
Cheap calcium content up to 40%, and only in sufficient stomach acid conditions can better absorb the best.
During meals or shortly after meals,  buffered lactic acid secretion in the highest dietary calcium intake, the absorption rate is relatively high.
Calcium citrate is more expensive, than the calcium carbonate is low, at around 21%. Calcium citrate does not require stomach acid.
Effect can also be absorbed, so the elderly less gastric acid secretion, more suitable for eating this calcium.