TNAU Agritech Portal :: Sustainable Agriculture

Nutrients and its importance :: Micronutrients

MINERALS AND TRACE METALS

Bones and skeleton are made up mainly of calcium, magnesium and phosphorus, and iron is a component of blood. Minerals like zinc, molybdenum, copper, manganese and magnesium are either structural part or activate a large number of enzyme systems. Iodine is a part of hormone, thyroxine. Sodium, potassium is important elements present in fluids within and outside the cells and along with ions like chloride, bicarbonate and carbonate keep water and acid base balance.

Trace elements

Some of the important trace elements of relevance in human nutrition are zinc. Copper, selenium, cobalt, fluoride, manganese, chromium, iodine and molybdenum. Other trace elements are arsenic, nickel, vanadium and silicon. Essentially of some of the trace elements for humans are well established, viz., iodine, Zn, Cu, F, Mn, Cr.

Minerals	Functions in the Body	Food sources	Daily Allowances
Calcium	Hardness of bones, teeth transmission of nerve impulse Muscle contraction Normal heart rhythm Activate enzymes Increase cell permeability Catalyze thrombin formation	Milk, hard cheese Ice cream, cottage cheese Greens; turnip, collards, kale, mustard, broccoli Oysters, shrimp, salmon, clams	Infants: 360-540 mg Children:800 mg Teenagers:1,200 mg Adults: 800 mg Pregnancy: 1,200mg Lactation: 1,200 mg
Chlorine	Chief anion of extra cellular fluid Constituent of gastric juice Acid-base balance; chloride bicarbonate shift in red cells	Table salt	Estimate safe and adequate intake Infants 275-1,200 mg Children 500-2,775 mg Teenagers 1,400-4,200 mg Adults 1,700-5,100 mg Daily diet contains in excess of need
Chromium	Efficient use of insulin in glucose uptake; glucose oxidation, protein synthesis, stimulation of fat, and cholesterol synthesis Activation of enzymes	Liver, meat cheese whole-grain cereals	Estimated safe and adequate intake: Infants 0.01-0.06 mg Children 0.02-0.20 mg Teenagers 0.05-0.20 mg Adults 0.05-0.20 mg
Copper	Efficient use of insulin in glucose uptake; glucose oxidation, protein synthesis, stimulation of fat, and cholesterol synthesis Activation of enzymes	Liver, meat Cheese Whole-grain cereals	Estimated safe and adequate intake: Infants 0.01-0.06 mg Children 1.0-2.5 mg Teenagers 2.0-3.0 mg Adults 2.0-3.0 mg
Fluorine	Increases resistance of teeth to decay; most effective in young children Moderate levels in bone may reduce osteoporosis	Fluoridated water: 1 ppm	Estimated safe and adequate intake: Infants 0.1-1.0 mg Children 0.5-2.5 mg Teenagers 1.5-2.5 mg Adults 1.5-4.0 mg
Iodine	Constituent of diiodotyrosine, triiodothyronine, thyroxine; regulate rate of energy metabolism	Iodized salt is most reliable source Seafood Food grown in non-goitrous coastal areas.	Infants: 40-50 mg Children :70-120 mg Teenagers: 150 mg Adults: 150mg Pregnancy: 175 mg Lactation: 200mg
Iron	Constituent of hemoglobin, myoglobin, and oxidative enzymes: catalase, cytochrome, xanthine oxidase	Liver, organ meats Meat, poultry Egg yolk Enriched and whole-grain breads, millets such as bajra and ragi, Dark-green vegetables, Legumes Molasses, dark Peaches, apricots, prunes, raisins Diets supply about 6 mg per 1,000 mg	Infants: 10-15 mg Children :10-15mg Teenagers: 18 mg Men: 10mg Women: 18mg Pregnancy 18+ mg Lactation: 200mg
Magnesium	Constituents of bones, teeth Activates enzymes in carbohydrate metabolism Muscle and nerve irritability	Whole-grain cereals Nuts; legumes Meat Milk Green leafy vegetables	Infants 50-70 mg Children 150-250mg Women:300mg Men:350 mg Pregnancy and lactation: 450 mg
Manganese	Activation of many enzymes; oxidation of carbohydrates, urea formation, protein hydrolysis Bone formation	Legumes, nuts Whole-grain cereals	Estimated safe and adequate intake: Infants 0.5-1.0 mg Children 1.0-3.0 mg Teenagers 2.5-5.0 mg Adults 2.5-5.0 mg
Molybdenum	Cofactor for flavoprotein enzymes; present in xanthine oxidase	Organ meats Legumes Whole-grain cereals	Estimated safe and adequate intake: Infants 0.03-0.08 mg Children 0.05-0.31 mg Teenagers 0.15-0.50 mg Adults 0.15-0.50 mg
Phosphorus	Structure of bones, teeth cell permeability Metabolism of fats and carbohydrates: storage and release of ATP Sugar-phosphate linkage in DNA and RNA Phospholipids in transport of fats]Buffer salts in acid-base balance	Milk, cheese Eggs, meat, fish poultry Legumes, nuts Whole-grain cereals	In Infants: 200-400 mg Children :800mg Adults: 800mg Pregnancy: 1,200 mg Lactation: 1,200mg
Potassium	Principal cation of intracellular fluid Osmotic pressure; water balance; acid-base balance Nerve irritability and muscle contraction, regular heart rhythm Synthesis or protein	Widely distributed in foods Meat, fish, Cereals, Fruits, vegetables	Estimated safe and adequate intake: Infants: 350-1,275 mg Children :550-3,000 mg Teenagers: 1,525-4,575 mg Adults: 1,875-5,625mg Diet adequate in calories supplies ample amounts
Selenium	Antioxidant Constituent of glutathione oxidase	Meat and sea foods Cereal foods	Estimated safe and adequate intake: Infants0.01-0.06 mg Children :0.02-0.20 mg Teenagers: 0.05-0.20 mg Adults: 10.05-0.20 mg
Sodium	Principal cation of extracellular fluid Osmotic pressure; water balance Acid-base balance Regulate nerve irritability and muscle contraction “Pump” for active transport such as for glucose	Table salt Processed foods Milk Meat, fish, poultry	Estimated safe and adequate intake: Infants: 115-750 mg Children: 325-1,800 mg Teenagers: 900-2,700mg Adults: 1,100-3,300 mg Diet adequate in calories supplies ample amounts
Sulfur	Constituent of proteins, especially cartilage, hair, nails Constituent of melanin, glutathione, thiamin, biotin, coenzyme A, insulin High-energy sulfur bonds Detoxication reactions	Protein foods rich in sulfur amino acids Eggs Meat, fish, poultry Milk, cheese Nuts	Not established Diet adequate in protein meets need
Zinc	Constituent of enzymes; carbonic anhydrase, carboxypeptidase, lactic dehydrogenase	Sea foods Liver and other organ meats Meats, fish Wheat germ Yeast Plant foods are generally low Usual diet supplies 10 to 15 mg	Infants: 3-5 mg Children: 10 mg Teenagers: 15mg Adults: 15 mg Pregnancy:20 mg Lactation: 25 mg

Source
Robinson,C.N and Lawler, M.R 16 Edition. Normal and Therapeutic Nutrition. Oxford and IBH Publishing Co, Delhi.
Vijayapushpam et al. 2008, Micronutrients- the protective foods. NIN, Hyderabad.