A mineral is a chemical element required as an essential nutrient by organisms, other than carbon, hydrogen, nitrogen, oxygen and sulfur present in common organic molecules. The remaining elements are classed as minerals in the four groups of essential nutrients (the others are vitamins, essential fatty acids, and essential amino acids). The first six most-common major chemical elements (sometimes known as "major minerals") in order of abundance in the human body include calcium, phosphorus, potassium, sodium, chlorine, and magnesium. Calcium and phosphorus, as skeletal minerals comprising about 1.6 kg of an adult, make up 99% of the mass of the body along with the four non-mineral elements carbon, hydrogen, oxygen, and nitrogen. The last four major mineral elements (potassium, sodium, chlorine and magnesium) make up only about 0.85% of the weight of the body. Together these 11 chemical elements make up 99.85% of the body. All of the remaining functional elements in a human body are sometimes known as "trace elements." All of the trace elements together total less than 10 grams, less than the weight of the least common major mineral, magnesium. The trace elements necessary for mammalian life include iron, cobalt, copper, zinc, manganese, molybdenum, iodine, and selenium. Because inorganic mineral content of foods do not form volatile combustion products, nutrition analysis methods involving combustion may report the total mineral content of food as "crude ash". Over twenty minerals are necessary for mammals, and several more for various other types of life. The total number of chemical elements that are absolutely needed is not known for any organism. Ultratrace elements of some minerals such as silicon and boron are known to clearly have a role but the exact biochemical nature is unknown, and others such as arsenic and chromium are suspected to have a role in health, but with weaker evidence. Bromine has recently been found to have a biochemical role in the body in the synthesis of collagen, but these findings have not yet been confirmed. Most chemical elements that are ingested by organisms are in the form of simple compounds. Larger chemical compounds of elements need to be broken down for absorption. Plants absorb dissolved elements in soils, which are subsequently picked up by the herbivores that eat them, and the elements move up the food chain. Larger organisms may also consume soil (geophagia) and visit salt licks to obtain limiting minerals they are unable to acquire through other components of their diet. Bacteria and fungi play an essential role in the weathering of primary elements that results in the release of nutrients for their own nutrition and for the nutrition of others in the ecological food chain. One element, cobalt, is available for use by animals only after having been processed into complex molecules (e.g., vitamin B12) by bacteria. Scientists are only recently starting to appreciate the magnitude and role that microorganisms have in the global cycling and formation of biominerals.

Read full article on Wikipedia · CC-BY-SA