Minerals and nutrition

Dietary minerals are a group of inorganic chemicals required by humans for various body functions.

They are extracted from the earth’s crust by plants which are in turn consumed by animals and humans. The following minerals are essential for humans.

Calcium: This is the most abundant of all minerals in the body. Average adult body contains about 1200 grams of calcium (roughly 2% of body weight).

About 99 percent of calcium in the body is in the bones. Milk and other diary products are the major source of calcium. About 20-30 percent of dietary calcium is absorbed.

The calcium in breast milk is easily absorbed and about 60% is absorbed. Though cow’s milk has higher calcium content its absorption is less due to higher phosphate.

Calcium absorption is governed by the active form of vitamin D (1,25 dihydroxycholecalciferol) and the parathyroid hormone in turn regulates the level of vitamin D.

Calcium is responsible for lending strength to bones. It is also necessary for many vital functions.

Premature babies can suffer from calcium deficiency as most of the calcium is transferred during the third trimester. Hence they need calcium supplements.

Apart from helping in formation of bones and teeth calcium is vital for many important functions-coagulation of blood, contraction of muscles, heart function, milk production and transmitting electrical and chemical signals from cell membrane to the components inside the cell.

It is also essential for the transformation of light to electrical signals in the retina and hence is also important for normal vision.

In newborn babies decrease in level of calcium in the blood can cause convulsions.

Phosphorous: An adult body contains about 400-700 grams of phosphorous. About 80% of phosphorous is in the bones. Diary products, legumes, nuts, eggs and meat are rich sources of phosphorous. Roughly 80% of dietary phosphorous is absorbed.

The kidneys are responsible for maintaining phosphorous level. Parathyroid hormone decreases re-absorption of phosphorous from the kidneys and increases its elimination.

Phosphorous is an essential component of many important organic compounds like ATP (Adenosine Tri Phosphate which supplies energy for all functions of body) and 2-3 diphosphoglycerate a substance present inside red blood cells which regulates the movement of oxygen from red blood cells to other tissues.

Cell membranes contain phospholipids which also contain phosphorous. Nucleotides, the structural units of DNA also contain phosphorous.

Nutritional phosphorous deficiency is rare. It can occur is preterm babies and can lead to osteoporosis and rickets.

Magnesium: An adult body contains about 25 gram of magnesium. Approximately 50% of this is in bones. Vegetables, cereals and nuts are rich in magnesium. Isolated dietary magnesium deficiency is not known.

The kidneys control the level of magnesium by reducing excretion when intake is low. Magnesium deficiency can occur in malabsorption and kidney disease.

Sodium: This is found in all body fluids. It is found in many foods and is also added while cooking in the form of sodium chloride. It is excreted in urine and sweat. People indulging in vigorous activity which leads to lot of sweating need more sodium. Its depletion causes muscle cramps.

An adult body contains about 100 grams of sodium ion. Sodium is lost from the body during diarrhea and vomiting which is common in children.

Potassium: Adult body contains about 250 grams of potassium. It is widely distributed in foodstuffs. Hence dietary deficiency does not occur. Depletion can occur in diarrhea, vomiting and severe malnutrition.

Potassium is the principle intracellular cation. Potassium deficiency can cause muscle weakness and mental confusion. Sudden death can occur due to abnormal heart rhythm.

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