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The name "calcium" itself derives from the Latin word calx "lime". [34] Vitruvius noted that the lime that resulted was lighter than the original limestone, attributing this to the boiling of the water. In 1755, Joseph Black proved that this was due to the loss of carbon dioxide, which as a gas had not been recognized by the ancient Romans. [39]
The US Institute of Medicine (IOM) established Recommended Dietary Allowances (RDAs) for calcium in 1997 and updated those values in 2011. [6] See table. The European Food Safety Authority (EFSA) uses the term Population Reference Intake (PRIs) instead of RDAs and sets slightly different numbers: ages 4–10 800 mg, ages 11–17 1150 mg, ages 18–24 1000 mg, and >25 years 950 mg. [10]
For example, for calcium the U.S. Food and Drug Administration set the recommended intake for adults over 70 years at 1,200 mg/day and the UL at 2,000 mg/day. [19] The European Union also sets recommended amounts and upper limits, which are not always in accord with the U.S. [ 20 ] Likewise, Japan, which sets the UL for iodine at 3000 μg ...
Calcium deposits, primarily composed of calcium carbonate (CaCO 3), react with weak acids to form calcium salts that are soluble in water. The general reaction can be represented as follows: CaCO 3 + 2H + → Ca + 2 + CO 2 + H 2 O. Here, H + represents the hydrogen ions provided by the acid
Calcium formate is shown to be more readily absorbed form of calcium than calcium carbonate and calcium citrate. [7] No optic nerve damage has been observed with calcium formate supplementation – along with formaldehyde , formate is a major metabolic product of methanol , which can cause blindness upon ingestion.
Calcium regulation in the human body. [6]The plasma ionized calcium concentration is regulated within narrow limits (1.3–1.5 mmol/L). This is achieved by both the parafollicular cells of the thyroid gland, and the parathyroid glands constantly sensing (i.e. measuring) the concentration of calcium ions in the blood flowing through them.
The calcium cycle is a transfer of calcium between dissolved and solid phases. There is a continuous supply of calcium ions into waterways from rocks, organisms, and soils. [1] [2] Calcium ions are consumed and removed from aqueous environments as they react to form insoluble structures such as calcium carbonate and calcium silicate, [1] [3] which can deposit to form sediments or the ...
Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue, [1] [2] causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification. [3]