Dietary minerals are the chemical elements required by living organisms, other than the four elements Carbon, Hydrogen, Nitrogen, and Oxygen which are ubiquitous in organic molecules. They can be either bulk minerals (required in relatively large amounts) or trace minerals (required only in very small amounts).
These can be naturally occurring in food or added in elemental or mineral form, such as calcium carbonate or sodium chloride. Some of these additives come from natural sources such as ground oyster shells. Sometimes minerals are added to the diet separately from food, as vitamin and mineral supplements and in dirt eating, called pica or geophagy.
Appropriate intake levels of each dietary mineral must be sustained to maintain physical health. Excessive intake of a dietary mineral may either lead to illness directly or indirectly because of the competitive nature between mineral levels in the body. For example, large doses of zinc are not really harmful unto themselves, but will lead to a harmful copper deficiency (unless compensated for, as in the Age-Related Eye Disease Study).
Soils in different geographic areas contain varying quantities of minerals.
Bulk Minerals
In human nutrition, the dietary bulk mineral elements (RDA > 200 mg/day) are (in alphabetical order): Calcium Chloride Magnesium Phosphorus Potassium Sodium Sulfur
Trace Minerals
The most important trace mineral elements (RDA < 200 mg/day) are (again, in alphabetical order): Chromium Cobalt Copper Fluorine Iodine Iron Manganese Molybdenum Selenium Zinc
Iodine is required in larger quantities than the other trace minerals in this list and is sometimes counted with the bulk minerals. Sodium is not generally found in dietary supplements, despite being needed in large quantities, because the mineral is so common in food. This list is not an endorsement of the need of any of these minerals as dietary supplements.
Other Minerals
Many other minerals have been suggested as required in human nutrition, in varying quantities. Standards of evidence vary for different elements, and not all have been definitively established as essential to human nutrition. Common candidates include:
(elements for which convincing scientific evidence is lacking are marked as suspect) Arsenic Bismuth (suspect) Boron Nickel Rubidium (suspect) Silicon Strontium (suspect) Tellurium (suspect) Titanium (suspect) Tungsten (some organisms use tungsten rather than molybdenum) Vanadium
Various other elements found in food supplies may vary from holding no known nutritional value (such as silver) to being toxic (such as mercury).
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