Search results
Results from the WOW.Com Content Network
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]
On the other hand, the metal in pure form has few applications due to its high reactivity; still, in small quantities it is often used as an alloying component in steelmaking, and sometimes, as a calcium–lead alloy, in making automotive batteries. Calcium is the most abundant metal and the fifth-most abundant element in the human body. [8]
Calcium makes up 920 to 1200 grams of adult body weight, with 99% of it contained in bones and teeth. This is about 1.5% of body weight. [ 2 ] Phosphorus occurs in amounts of about 2/3 of calcium, and makes up about 1% of a person's body weight. [ 10 ]
Calcium citrate is recommended for patients with achlorhydria and those on medications that decrease stomach acidity. While calcium carbonate is the most common and least expensive form of calcium and contains 40% of elemental calcium, calcium citrate supplements contain only 21% calcium, requiring more tablets for equivalent dosage.
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
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
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.
The dioctahedral sheet of nontronite is composed mainly of trivalent iron (Fe 3+) cations, although some substitution by trivalent aluminium (Al 3+) and divalent magnesium (Mg 2+) does occur. The tetrahedral sheet is composed mainly of silicon (Si 4+ ), but can have substantial (about 1 in 8) substitution of either Fe 3+ or Al 3+ , or ...