Mineral (nutrient)

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 dieticians 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.

Macrominerals

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 and digestive system health, builds bone, neutralizes acidity, clears toxins, helps blood stream)
• Chloride
• Magnesium required for processing ATP and related reactions (health, builds bone, causes strong peristalsis, increases flexibility, increases alkalinity)
• Phosphorus required component of bones (see apatite) and energy processing and many other functions (bone mineralization)
• Potassium required electrolyte (heart and nerves health)
• Sodium electrolyte
• Sulfur for three essential amino acids and many proteins and cofactors (skin, hair, nails, liver, and pancreas health)

Trace minerals

Some trace mineral elements (RDA < 200 mg/day) are (alphabetical order):

• Cobalt required for biosynthesis of vitamin B12 family of coenzymes
• Copper required component of many redox enzymes, including cytochrome c oxidase
• Fluorine for tooth enamel which contains fluoroapatite (see Water fluoridation controversy)
• Iodine required for the biosynthesis of thyroxin
• Iron required for many proteins and enzymes, notably hemoglobin
• Manganese (processing of oxygen)
• Molybdenum required for xanthine oxidase and related oxidases
• Nickel present in urease
• Selenium reqiured for peroxidase (antioxidant proteins)
• Vanadium (dubious, although it is found in lower organisms)
• Zinc required for several enzymes such as carboxypeptidase, liver alcohol dehydrogenase, carbonic anhydrase. Zinc is pervasive.

Iodine is required in larger quantities than the other trace minerals in this list and is sometimes classified with the bulk minerals. Sodium is not generally found in dietary supplements, despite being needed in large quantities, because the ion is very common in food. Many other elements 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. Candidates include:

Elements for which convincing scientific evidence is lacking are marked as suspect:

• Bismuth (component of the "Peptobismol")
• Boron (Increases bone density)
• Bromine
• Chromium is speculated to be required in trace amounts for sugar metabolism in humans.
• Indium (Suspect. It may enhance the absorption of all other minerals in a healthful matter. It may also help the healthy mineralization of organs.)
• Rubidium (suspect)
• Silicon (proposed to be relevant to bone and cartilage formation, but role of silicon in human health remains controversial).
• Tellurium (suspect)
• Titanium (suspect)
• Tungsten (some organisms utlilize tungsten in place of molybdenum.)

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

A large body of research suggests that humans often can benefit from mineral supplementation. This is especially true for humans consuming a low variety of foods. Vitamins and minerals are interdependent, requiring the presence of one another for full benefit; taking a multivitamin without minerals is not nearly as effective as taking one with minerals. Extensive university research also demonstrates that the most bioavailable form of supplemental mineral is the chelated mineral (one that is bonded to a specific-size amino acid).

See also

• Macronutrient
• Micronutrient
• Essential nutrient

External links

• Metals in Nutrition
• The Minerals in Your Food
• Minerals in human nutrition

References

Donatelle, Rebecca J. (2005). Health, The Basics. 6th ed. San Francisco: Pearson Education, Inc.