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,[2] 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
