Minerals
Dietary minerals are the chemical elements essential to living organisms, other than the four basic elements namely carbon, hydrogen, nitrogen and oxygen that are present in nearly all organic molecules.
We use the term "mineral" to describe simply the less common elements in the diet. Some are heavier than the four mentioned, including several metals, which often occur as ions (electrically charged chemical species) in the body.
All known forms of life require a subtle and complex electrolyte balance between the intracellular and extracellular environments. In particular, this balance is important for the regulation of body hydration and blood pH, and is critical for nerve and muscle functions.
Muscle tissue and neurons are both electrically charged tissues of the body. Muscles and neurons are activated by electrolyte activity between the extracellular fluid or interstitial fluid, and intracellular fluid. Electrolytes may enter or leave the cell membrane through specialized protein structures embedded in the membrane plasma called ion channels. For example, muscle contraction depends on the presence of calcium (Ca 2 +), sodium (Na +) and potassium (K +). Without adequate levels of these essential electrolytes, muscle weakness or severe muscle contractions may occur.
Some dieticians recommend that these be supplied from foods in which they occur naturally, or at least as complex compounds, or sometimes even from natural inorganic sources (such as calcium carbonate from crushed oyster shells). Some minerals are absorbed much more readily in the ionic forms found in such sources. On the other hand, minerals are often artificially added to the diet as supplements, the most famous is probably iodine in iodized salt, which prevents goitre.
There are two categories of minerals according to the amount necessary for the proper metabolic functioning :
- The principal elements or macronutrients for which nutritional intakes greater than 400 mg are recommended:
- Calcium (Ca)
- Chlorine (Cl)
- Magnesium (Mg)
- Phosphorus (P)
- Potassium (K)
- Sodium (Na)
- TTrace elements for which recommended dietary intakes are below 20 mg:
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