Dietary mineral
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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 hypothesized to be a means of supplementing the diet with elements, but this has not been verified [1]. 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.[2] 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.
Dietary_minerals.PNG/250px-Periodic_table_of_the_chemical_elements_(1-118)Dietary_minerals.PNG)
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[edit] Essential minerals
At least seven minerals are required to support biochemical processes, many playing a role as electrolytes or in cell structure and function.[3] In human nutrition, the dietary bulk "mineral elements" (RDA > 200 mg/day) are in alphabetical order (parenthetical comments on folk medicine perspective):
- Calcium (for muscle, heart and digestive system health, builds bone, neutralizes acidity, supports synthesis and function of blood cells)
- Chloride (for production of hydrochloric acid in the stomach and in cellular pump functions)
- Magnesium is required for processing ATP and related reactions (health, builds bone, increases alkalinity)
- Phosphorus is a component of bones (see apatite) and energy processing and many other functions (bone mineralization)[4]
- Potassium is a systemic electrolyte and is essential in coregulating ATP with sodium
- Sodium is a systemic electrolyte and is essential in coregulating ATP with potassium
[edit] Trace minerals
Numerous minerals are required in trace amounts and are usually cofactors for enzymes.[2] Some trace mineral elements (RDA < 200 mg/day) are (alphabetical order):[citation needed]
- Cobalt is required for biosynthesis of vitamin B12 family of coenzymes
- Copper is required component of many redox enzymes, including cytochrome c oxidase
- Fluorine participates in formation of tooth enamel which contains fluoroapatite (see Water fluoridation)
- Iodine is required for the biosynthesis of thyroxine
- Iron is required for many proteins and enzymes, notably hemoglobin
- Manganese is a cofactor in function of antioxidant enzymes such as superoxide dismutase
- Molybdenum is required for xanthine oxidase and related oxidases
- Nickel is present in urease
- Selenium is required for peroxidase (antioxidant proteins)
- Sulfur is an essential component of cysteine and methionine amino acids and participates as an enzyme cofactor
- Zinc is pervasive and required for several enzymes such as carboxypeptidase, liver alcohol dehydrogenase, carbonic anhydrase
[edit] Other trace minerals
Many elements have been suggested as required in human nutrition, but such claims have usually not been scientifically proven. One problem with identifying efficacy is 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 trace elements still lacking solid proof, chromium is often cited.[5] Chromium(III) is implicated in sugar metabolism in humans, leading to a market for chromium picolinate.
- Vanadium (There is no established RDA for vanadium. No specific biochemical function has been identified for it in humans, although vanadium is found in other organisms)
[edit] Food sources
- Dairy products, calcium-fortified foods, canned fish with bones (salmon, sardines), and green leafy vegetables for calcium
- Nuts, soy beans, and cocoa for magnesium
- Table salt (sodium chloride, the main source), sea vegetables, olives, milk, and spinach for sodium
- Legumes, potato skin, tomatoes, and bananas for potassium
- Table salt is the main dietary source for chlorine
- Meat, eggs, and legumes for sulfur
- Red meat, leafy green vegetables, fish (tuna, salmon), eggs, dried fruits, beans, whole grains, and enriched grains for iron
[edit] See also
[edit] External links
[edit] References
- ^ Nchito M, Geissler PW, Mubila L, Friis H, Olsen A (2004). "Effects of iron and multimicronutrient supplementation on geophagy: a two-by-two factorial study among Zambian schoolchildren in Lusaka". Trans R Soc Trop Med Hyg. 98 (4): 218–27. doi:. PMID 15049460.
- ^ a b Lippard, Stephen J.; Jeremy M. Berg (1994). Principles of Bioinorganic Chemistry. Mill Valley, CA: University Science Books, 411. ISBN 0935702725.
- ^ Nelson, David L.; Michael M. Cox (2000-02-15). Lehninger Principles of Biochemistry, Third Edition, 3 Har/Com, W. H. Freeman, 1200. ISBN 1572599316.
- ^ Corbridge, D. E. C. (1995-02-01). Phosphorus: An Outline of Its Chemistry, Biochemistry, and Technology, 5th, Amsterdam: Elsevier Science Pub Co, 1220. ISBN 0444893075.
- ^ Stearns DM (2000). "Is chromium a trace essential metal?". Biofactors 11 (3): 149–62. PMID 10875302.
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