MINERALS
MINERALS
• Minerals are inorganic elements required by the body in varying amounts to carry out various functions.
• Occur in food as salts, e.g., sodium chloride, calcium phosphate and ferrous sulphate.
• Constitute 4% of our body weight.
• Unlike macronutrients, they do not furnish energy.
• Like vitamins, are required in very small quantities and are vital to body.
Classification
Classified into 3 main groups
• Major minerals or macro-minerals: 7 minerals are required in large amounts of over 100 mg/day. e.g., calcium, phosphorus, sodium, chlorine, potassium, magnesium, and sulphur.
• Minor minerals: Required in small quantities, less than 100 mg/day, e.g., iron and manganese.
• Trace minerals: A few micrograms to a few milligrams are required per day, e.g., iodine, fluorine, zinc and molybdenum.
Functions
of Mineral
• It forms the structural components of bones, teeth, and muscles, e.g., calcium, phosphorus, and manganese in bones.
• They regulate activity of nerves with regard to stimuli and contraction of muscles, e.g., calcium.
• Maintain acid-base balance of body fluids, e.g., sodium and chlorine.
• They control water balance by means of osmotic pressure and permeability of cell membranes, e.g., sodium and potassium.
• They are constituents of vitamins, e.g., thiamine contains sulphur and cyanocobalamin contains cobalt.
• They form part of molecules of hormones and enzymes, e.g., iodine in thyroxine and zinc in insulin.
• They activate enzymes, e.g., calcium activates enzyme lipase.
• They regulate cellular oxidation. E.g., iron and manganese.
• Necessary for clotting of blood. E.g., calcium.
Calcium
• Adult body contain 1.2 kg of calcium and 99% is present in bones and teeth.
• Bones provide :
q A rigid framework for the body
q Reserves of calcium
• The remaining 1% is distributed in extracellular and intracellular fluids and has following functions:
Calcium acts as a catalyst in blood clotting
q It increases permeability of cell membranes thus helping absorption
q It regulates contraction and relaxation of muscles including heart beat
q It activates number of enzymes such as pancreatic lipase and acts as co-factor
• Sources
q Milk and milk products excluding butter, ghee and cream
q Ragi, green leafy vegetables esp. Drumstick leaves, cabbage, curry leaves, carrot, etc.
q Small dried fish, nuts and oilseeds
q Betel leaf with slaked lime
• Deficiency
q A severe deficiency leads to rickets in children and osteomalacia and osteoporosis in adults.
q Osteoporosis – Bones becomes porous and causes loss in height, back and hip pain.
q Tetany – A decrease in serum calcium levels causing intermittent spasms of the muscles of hands and feet with muscular pain.
Iron
• Human body contains 3-5 gm of iron of which 70% is in haemoglobin.
• Functions:
q Essential for carrying O2 to the lungs where O2 is released and C O2 is picked up to be exhaled by haemoglobin in red blood cells.
q Essential part of several oxidative enzymes.
q Helps in specific brain functions such as a good attention span and capacity to learn and memorize.
q Facilitates the complete oxidation of carbohydrates, proteins, and fats with-in the cell and release of energy for performing physical work.
Iron is present in two forms i.e. Haeme iron is 40% in flesh food while 60% is non-haeme iron. Non-haeme is larger portion of iron in food.
• Sources
q Liver, organ meats, shellfish, lean meat, egg yolk
q Green leafy vegetables, whole grain and enriched cereals, legumes and jaggery
q Garden cress seeds and niger seeds
q Peaches, apricots, manukas and figs
q Use of iron cooking utensils
• Deficiency
q Iron deficiency or anaemia. Haemoglobin level may be low. Symptoms – general fatigue, giddiness, breathlessness on exertion, paleness of skin etc.
q Normal level females: 11.5 -14.5 g%
q Normal level males: 12.5 – 16.5 g%
Sodium
• Sodium chloride or common salt is a daily ingredient in our diet. Adult body contains 180 g of sodium mostly present in extracellular fluid of body.
• Functions:
q Maintaining fluid balance and normal osmotic pressure between intracellular and extracellular compartments.
q Maintains normal irritability of nerves and helps in muscle contraction.
q Regulates the alkalinity and acidity of body fluids along with mineral chloride.
q Regulates cell permeability or passage of substances into and out of the cell.
• Sources:
q Salt, Milk, egg white, meat, poultry, green leafy vegetables, Bengal gram dal, beetroot and knolkhol etc.
• Deficiency:
q Seen in people with heavy physical activities. May occur in cases of severe vomiting and diarrhoea. Results in weakness, giddiness, nausea and muscle cramps.
• Excess:
q It leads to hypertension. Low-sodium diet is preferred.
Iodine
• Most of it is found in thyroid gland
• Only function is as a constituent of thyroxine
• The thyroid hormone regulates the rate of oxidation within the cells. The iodine absorbed is in incorporated into amino acid tyrosine to form the hormone thyroxine
Iodine +Tyrosine => Thyroxine
• If intake of iodine is inadequate, the stores of thyroxine are gradually depleted and the thyroid gland enlarges in an attempt to produce the necessary thyroxine.
• Sources:
q Seafood contains maximum iodine and fruits contain least.
q Iodized salt.
• Deficiency:
q Occurs when iodine content of soil is low that insufficient iodine is obtained through food, e.g. Soil in Kangra valley is iodine deficient
q Goitre
• Symptoms:
q Enlargement of thyroid gland
Cretinism in children (stunted growth).It is characterized by low BMR, flabby and weak muscles, dry skin. Mental retardation is observed.
Fluorine
• Normal constituent of the body, found mainly in bones and teeth.
• Small amounts of flourine bring striking reductions in tooth decay probably because the tooth enamel is made more resistant to the action of acids produced by bacteria in mouth.
• Sources:
q Milk, eggs and fish are important sources.
q Flouridation of water to ensure a concentration of 1 ppm is a safe and economical way to reduce the incidence of dental carries.
• Deficiency
q Results in dental carries and is seen in areas where drinking water contains less than 0.5 ppm of flourine.
q Adding fluorine at a level of 1 ppm reduces the incidence of dental carries by 50 %.
• Fluorosis
q Fluorosis or mottling of teeth occurs in parts of the world where drinking water contains excessive amounts of flourine, i.e. 3-5 ppm. Teeth lose their lustrous appearance. Enamel becomes dull and unglazed and chalky white patches are seen.
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