CALCIUM CITRATE POWDER
Calcium citrate is the calcium salt of citric acid. It is commonly used as a food additive (E333), usually as a preservative, but sometimes for flavor. In this sense, it is similar to sodium citrate. Calcium citrate is also used as a water softener because the citrate ions can chelate unwanted metal ions. Calcium citrate is also found in some dietary calcium supplements (e.g. Citracal). Calcium makes up 21% of calcium citrate by weight.
Bioavailability of calcium is debated, found to be equal to that of the cheaper calcium carbonate, or up to 2.5 times higher. Due to the possibility of higher absorption, patients who have undergone the Roux-en-Y variety of weight-loss surgery (also known as gastric bypass) are usually instructed to take calcium citrate as a dietary supplement.