Important role of minerals
Minerals are inorganic substances and unlike vitamins, always retain their chemical identity in the body until excreted. Minerals can’t be destroyed by heat, air, acid, or mixing. Minerals can only be lost from food when they leach into cooking water, that is then poured down the drain. Like the water-soluble vitamins, potassium are easily absorbed into the blood, transported freely and readily excreted by the kidneys. Calcium are more like fat-soluble vitamins, in that they must have carriers to be absorbed and transported and can be toxic in excess.
Minerals are components of body tissues and fluids that work in combination with enzymes, hormones, vitamins and transport substances. Minerals participate in nerve transmission (magnesium, potassium, sodium) muscle contraction (iron, calcium, magnesium, potassium, sodium) cell permeability (phosphorus), tissue structure (fluoride, calcium, magnesium, phosphorus) blood formation (iron, copper), acid-base balance (phosphorus), fluid regulation (potassium, sodium), protein metabolism (zinc, magnesium) immunity (zinc, selenium, calcium, magnesium) and energy production (chromium, iron). Minerals work either in combination with each other or as antagonists to each other. Some minerals compete with each other for absorption, while certain minerals enhance the absorption of other minerals.
INTERACTIONS among the trace minerals are common and well coordinated to meet the body’s needs e.g. several trace minerals support insulin’s work, influencing it’s synthesis, storage, release and action. Sodium interacts with calcium: when sodium intakes are high, calcium and sodium are excreted. Magnesium absorption is limited, when phosphorus intakes are high. Sometimes an excess of one may cause a deficiency of another e.g. manganese overload may aggravate iron deficiency. A deficiency of one may interfere with the work of another e.g. selenium deficiency halts the activation of the iodine-containing thyroid-hormones. A deficiency of a trace mineral may even open the way for a contaminant mineral to cause a toxic reaction e.g. iron deficiency makes the body more vulnerable to lead poisoning.
Minerals help maintain the delicate water balance, which is essential for the proper functioning of the mental and physical processes. They keep blood and tissue fluids from becoming too acid or too alkaline and permit other nutrients to pass into the blood stream. They also help draw chemical substances in and out of the cells and aid in the creation of antibodies.
Minerals act as catalysts for many biological reactions within the human body, including muscle response, transmission of messages through the nervous system, digestion and metabolism or utilization of nutrients in foods. They are important in the production of hormones.
A mineral is considered ESSENTIAL when:
- There is deficiency symptoms ( due to dietary lack), which respondswhen the mineral is reinstated.
- Improves health
- Necessary component of tissue, fluids / regulatory process (enzymatic reaction)
- Necessary constituent of another essential nutrient.
Minerals compose 4% of the body’s weight. Most of the minerals are found in the skeletal structure – calcium and phosphorus compose about ¾ of the adult’s bodily mineral content. To classify as a major mineral/ MACRONUTRIENT, a mineral must make up no less than 0.001% of the body weight – they are calcium, phosphorus, magnesium, potassium, sodium, and chloride. MICRONUTIENTS (trace minerals) are iron, iodine, zinc, selenium, silicon, copper, chromium, cobalt, fluoride, manganese, molybdenum, nickel, arsenic, tin , vanadium. To classify a mineral as either major or trace, does NOT reflect it’s importance – a deficiency in either one can be equally devastating.
Minerals can be found in their ionic state or bound to substances like proteins (iron in haemoglobin) or vitamins (cobalt in vitamin B12). This allow minerals to be more versatile in their biological roles.
The body’s concentration of minerals is maintained within narrow limits through absorption from the gut; excretion through the kidneys; bile secretions; storage; utilization; mineral-mineral competition. The average adult male excretes 20-30 g of inorganic substances each day, although the daily intake vary enormously from one individual to the other. Some trace minerals like iron, selenium and zinc are essential in small amounts, but toxic in large doses.
Absorption of the divalent ions is slower than absorption of the monovalent ions e.g. sodium (monovalent) is absorbed twice as fast as calcium (divalent). Absorption also depends on the body’s need for the mineral, as well as substances in the gut that may enhance or impede intestinal uptake.