Word Origin & History. critical 1580s, censorious, from critic + -al (1). Meaning pertaining to criticism is from 1741; medical sense is from c.1600; meaning of the nature of a crisis is from 1640s; that of crucial is from 1841.
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.alcium citrate is also found in some dietary calcium supplements (e.g. Citracal).
Many natural calcium carbonate preparations such as oyster shells or bone meal contain some lead. The low lead levels in calcium supplements are unlikely to be a health risk because calcium blocks lead absorption. Calcium citrate is well absorbed in the fasting state. Calcium doses above 500 mg are not absorbed as well as smaller doses, so large doses of supplements should be taken in divided doses (eg, in the morning and evening).