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Dietary minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen which are present in common organic molecules. The term "mineral" is archaic, since the intent of the definition is to describe ions, not chemical compounds or actual minerals. Furthermore, once dissolved, so-called minerals do not exist as such, sodium chloride breaks down into sodium ions and chloride ions in aqueous solution. Some dietitians recommend that these heavier elements should be supplied by ingesting specific foods (that are enriched in the element(s) of interest), compounds, and sometimes including even minerals, such as calcium carbonate. Sometimes these "minerals" come from natural sources such as ground oyster shells. Sometimes minerals are added to the diet separately from food, such as mineral supplements, the most famous being iodine in "iodized salt." Dirt eating, called pica or geophagy is practiced by some as a means of supplementing the diet with elements. The chemical composition of soils will vary depending on the location.
Vitamins, which are not considered minerals, are organic compounds, some of which contain heavy elements such as iodine and cobalt. The dietary focus on "minerals" derives from an interest in supporting the biosynthetic apparatus with the required elemental components. Appropriate intake levels of certain chemical elements is thus required to maintain optimal health. Commonly, the requirements are met with a conventional diet. Excessive intake of any element (again, usually as an ion) will lead to poisoning. For example, large doses of selenium are lethal. On the other hand, large doses of zinc are less dangerous but can lead to a harmful copper deficiency (unless compensated for, as in the Age-Related Eye Disease Study).
Dietary minerals classified as "macromineral" are required in relatively large amounts. Conversely "microminerals" or "trace minerals" are required relatively in minute amounts. There is no universally accepted definition of the difference between "large" and "small" amounts.
A variety of elements are required to support the biochemical processes, many play a role as electrolytes or in a structural role. In Human nutrition, the dietary bulk "mineral elements" (RDA > 200 mg/day) are in alphabetical order (parenthetical comments on folk medicine perspective):
A variety of elements are required in trace amounts, unusually because they play a role in catalysis in enzymes. Some trace mineral elements (RDA < 200 mg/day) are (alphabetical order):
Other trace minerals
Many elements have been suggested as required in human nutrition, but such claims are often suspect as pseudoscience. One problem with identifying efficacyis arises because many elements are innocuous at low concentrations, so proof of efficacy is lacking. Definitive evidence for efficacy comes from characterization of a biomolecule with an identifiable and testable function. Of the many ultratrace elements still lacking solid proof, chromium is often cited. Chromium(III) is implicated in sugar metabolism in humans, leading to a market for chromium picolinate.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Dietary_mineral". A list of authors is available in Wikipedia.|