Sources of essential minerals
About 4 percent of the body weight is made up of essential mineral elements. They are calcium, phosphorus, potassium, sulphur, sodium, chlorine, chlorine, iron, zinc, copper, iodine, magnesium, manganese, molybdenum, selenium and chromium .
Essential minerals required by the body
Macrominerals are present principally in body fluids as electrolytes and tissues as structural components. And trace elements are present in tissues.
All these minerals have diverse and critical functions in human metabolism, so they are called essential minerals that should be included in diet.
Essential trace minerals (elements) have vital roles in enzymatic reactions. They functions as part of enzyme reactions, either as a constituent part of the enzyme or as activators of enzyme systems. They have also a structural and catalytic role in gene expression.
Another function of trace minerals include the storage and transport of substrates as metalloproteins, for example zinc and insulin in secretory vesicles in the beta cells in the pancreas.
Cobalt is also required only as preformed vitamin B12, fluorine is not essential but is beneficial as fluoride.
Let's discuss details about essential materials required by the body:
Calcium
Calcium is a essential structural component of the bones where 99 percent of calcium is found.
Function of calcium
Calcium also plays important role in the coagulation of blood and mechanism of muscle contraction.
Dietary sources of calcium
Calcium can be got abundantly from milk ,cheese, eggs, fish, green vegetables.
Daily requirement of calcium
Normally daily requirements of calcium are 700 mg for normal adults and are higher in pregnant women and growing children .
Calcium deficiency may occur usually due to deficiency of vitamin D because absorption of calcium from intestinal tract is vitamin D-dependent.
Phosphorus / phosphate
Phosphorus is another essential element required for normal growth and development of the body. It is non metallic and highly reactive element which is present in the nature only in combined forms, predominantly with calcium in rock or bone. The common form of phosphorus in the nature is phosphate.
At normal condition, human body contains approximately 0.6 to 1.1 % phosphorus of total mass of the body. About 85 percent of phosphorus is found in bones and teeth in phosphate form. And rest of phosphorus is in the soft tissues where it takes part in metabolic reaction. Half to two third of the phosphorus in blood is in red blood cells ( erythrocytes).
Function of phosphorus
The main function of phosphorus is to build and repair bones and teeth, help nerves function, and make muscle contract.
It in association with calcium and vitamin D helps hardening bones and teeth.
In serum, phosphate ion has important role in acids /base balance (buffering).
In cells, phosphorus is important in the structure of nucleic acids (DNA, RNA) and phospholipids in cell membranes.
In cell energy metabolism, it involves in production of ATP (Adinosine triphosphatase) , which is source of energy.
Dietary sources of phosphorus/phosphate
All natural foods like milk, cheese, liver, kidneys, meat, oat meal, nuts, legumes, fish, bread are the richest dietary sources of phosphorus.Daily requirement of phosphorus/phosphate
Normally daily requirements of phosphorus/phosphates are 550 mg for normal adults and are higher in pregnant women and growing children .
As phosphates are present in all natural foods, deficiency of phosphate is rare except starvation.
Deficiency of phosphorus causes hypophosphataemia and consequent cellular dysfunction which manifests as anorexia, muscle weakness, bone pain, rickets, osteoporosis, osteomalacia, debility, increased susceptibility to infection, paraesthesia (abnormal sensation of skin), ataxia (neurological signs which lacks voluntary coordination of muscle movement),confusion, and ultimately death.
Sodium
Sodium is key element in human body. It is most commonly occurring extracellular cation and is associated with:
- contraction of muscles
- transmission of nerve impulses along axons
- maintenance of the electrolyte balance in the body.
A normal blood sodium level is 135 to 145 mEq/L. When blood sodium level comes below 135 mEq/L , hyponatremia occurs .
Dietary sources of sodium
Most of foods, especially fish, meat,eggs, milk, artificially enriched bread and as cooking and table salts are dietary sources of sodium.
Daily requirement of sodium
Daily requirement of sodium is 1.6 grams.
Potassium
Potassium is an important mineral or element that functions as an electrolyte in the body. It mostly occurs as intracellular cation to regulate fluid balance, involves many chemical activities within cells and concisely to say, it is associated with :
- contraction of muscles
- transmission of impulses
- maintenance of the electrolyte balance in the body.
Potassium is third most abundant mineral in the body. About 98 percent of potassium in body is found in cells. Of this, 80 percent is found in muscle cells, while 20 percent of potassium is found in bones, liver and red blood cells.
Dietary sources of potassium
Vegetables, fruits, juice, milk and meat are the dietary sources of potassium.
Note that potassium rich diet may reduce blood pressure and water retention, protect from strokes and help prevent osteoporosis and kidney stones.
Daily requirement of potassium
At normal condition daily requirement of potassium is 3.5 g which is excess in comparison of sodium.
How do sodium and potassium maintain electrolyte balance in body ?
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| Representative diagram of extracellular fluid compartments and intracellular fluid compartments |
At normal condition, a 70 kg weight adult man's body contains about 42 litres water(fluid), ie total body water is 60 percent of the body weight. The percentage of water(fluid) in the body depends on the age , gender and degree of obesity.
Nearly 28 of the 42 litres of fluids in the body are inside the cells and are collectively called intracellular fluids (ICF). So, the intracellular fluids constitutes nearly 40 percent of the total body weight of in a normal person.
The remaining 14 litres of 42 liters of fluids are in the outside of the cells and are collectively called extracellular fluids (ECF). Thus extracellular fluids constitutes nearly 20 percent of the total body weight.
There are two largest compartments of the extracellular fluid: Interstitial fluid comprises 11 litres and ; the plasma comprises 3 litres.
It is very crucial to keep normal distribution of fluids between the intracellular and the extracellular compartments of the body.
The normal distribution of this fluids between the different body compartments is achieved and tightly controlled through several interlinked factors. Among these factors, sodium and potassium are important factors to regulate fluid balance between extracellular and intracellular compartments of the body.
The amount of fluids in the intracellular fluid compartments and extracellular fluid compartments is affected by their concentration of electrolytes, especially potassium and sodium.
Potassium is the main electrolyte in the intracellular fluids, and it determines amount of water inside cells. Conversely sodium is the main electrolyte in the extracellular fluids, and it determines the amount of water outside the cells.
Number of electrolytes per litre of fluid is called osmolarity of that fluid. Under normal conditions, the osmolarity is same inside and outside of the cells.
Total osmalarity of plama is 299.8 mOsm/L, that of interstitial fluid 300.8 mOsm/L, and that of Intracellular fluid is 301.2 mOsm/L. At 37°C, the total osmotic pressure (mmHg) of plasma is 5441 mOsm/L ,of interstitial fluid is 5423 mOsm/L , and of intracellular fluid is 5423 mOsm/L.
When osmalarity becomes unequal between two compartments, water from the side with fewer electrolytes will move into the side with more electrolytes to equalize electrolyte concentrations of fluid.
The movement of too much water from cells may cause them to shrink and the movement of too much water into cells may cause them to brust.
That's why , it's very important to consume right amount of sodium and potassium containing foods.
It is very important to maintain good fluid balance for optimal health. Poor fluid balance may cause dehydration or oedema in the body. Dehydration ultimately affects the heart and kidneys.
Adding a potassium rich food stuffs in diet and staying hydrated can help maintain good fluid balance
Iron
Iron is an essential element for the formation of red blood cells. It is also essential for the oxidation of carbohydrate and in the synthesis of some hormones and neuro transmitters.Deficiency of iron causes anemia. In normal adults about 1 mg of iron is lost from the body daily.
Dietary sources of Iron
Liver kidney, meat ,egg yolk, wholemeal bread, green vegetables, potatoes are the main dietary sources of iron.Daily requirement of Iron
The daily requirement of iron is 8.7 mg for men and 14.8 mg for women.Menstruating women and pregnant women needs more iron due to their physiological causes.
Iodine
Iodine is only one mineral element that is essential component for formation of thyroid hormones; thyroxine (T4) and triiodothyronine (T3).Dietary sources of Iodine
Salt water fish, meat, milk,seafood and vegetables grown in the soils containing iodine are dietary sources of iodine.
Daily requirement of iodine
Daily requirement of iodine is 140 micrograms.Deficiency of iodine causes goitre, swelling of neck resulting from enlargement of the thyroid gland.
Zinc
Zinc is essential transnational element exists in biology Zn++ cation and is cofactor more than 300 different enzymes in all branch of metabolism.Zinc is also a stabilizing structural component of several of several proteins.
Zinc also functions as antioxidant and plays important role in the immune system. It is also beneficial for wound healing.
Zinc supplementation may improve growth and development development of infants and children and improve immune response.
