FOOD SCIENCE AND NUTRITION

Second Edition

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Sunetra Roday

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CHAPTER 20Minerals

MineralsMinerals are inorganic elements required by the body in varying amounts to carry out various body functions. Classification Major minerals or macrominerals: Required in large

amounts of over 100 mg/day, e.g., calcium, phosphorus

Minor minerals: Required in small quantities, less than 100 mg/day, e.g., iron and manganese

Trace elements: A few micrograms to a few milligrams are required per day, e.g., iodine, fluorine

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Functions of Minerals Forms the structural components of bones, teeth, soft

tissues, blood, and muscles Regulates activity of nerves with regard to stimuli and

contraction of muscles Maintains acid–base balance of body fluids Controls water balance They are constituents of vitamins Form part of molecules of hormones and enzymes Activate enzymes Regulate cellular oxidation Necessary for clotting of blood

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CalciumFunctions Acts as a catalyst in clotting of blood Increases permeability of cell membranes thus helping in absorption Regulates contraction and relaxation of muscles Activates a number of enzymes

Factors affecting calcium absorption Body needs Gastric activity Vitamin D Lactose Ascorbic acid

SourcesMilk and milk products, ragi, green leafy vegetables, nuts and oilseeds, small fish

DeficiencyLeads to rickets in children and osteomalacia and osteoporosis in adults © Oxford University Press. All rights reserved

PhosphorusFunctions Building bones and teeth along with calcium and magnesium The nucleic acids needed for genetic coding contain phosphorus Regulate the absorption and transport of fats ATP and ADP are necessary for storing and releasing energy

according to body needs As part of enzymes needed for the metabolism of

carbohydrates, fats, and proteinsSourcesWidely distributed in foodsDeficiencyDeficiency is rare

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IronFunctions Essential for carrying O2 to the lungs An essential part of several oxidative enzymes Helps in specific brain functions Facilitates the complete oxidation of carbohydrates, proteins, and fats within

the cell and release of energy

Factors affecting iron absorption Body need Acidic medium Form of iron

SourcesLiver, organ, meat, shellfish, lean meat, egg yolk, peaches, apricots, green leafy vegetables, wholegrain and enriched cereals, jaggery, legumes, iron cooking utensils

DeficiencyCauses microcytic and hypochromic anaemia© Oxford University Press. All rights reserved

IodineFunctionsAs a constituent of thyroxine, it regulates rate of oxidation in the cell and determines rate of metabolismSourcesSaltwater fish and shellfish; iodine content of eggs, meat, dairy products depend on iodine content of diet of animal and plants depend on iodine content of soilDeficiencyDeficiency results in goitre, and cretinism in children

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FluorineFunctions Fluoride along with calcium forms tooth enamel Maintains bone structureSourcesMilk, eggs, fish, water, fluoridated water, topical applications of stannous fluoride by dentistsDeficiencyDeficiency results in dental cariesEffect of excessive fluorineFluorosis or mottling of teeth

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SodiumFunctions Maintains fluid balance and normal osmotic pressure Maintains normal irritability of nerves and helps in muscle

contraction Regulates the alkalinity and acidity of body fluids Regulates cell permeabilitySourcesMilk, egg white, meat, poultry, green leafy vegetables, bengal gram dal, beetroot, and knolkhol DeficiencyResults in weakness, giddiness, nausea, and muscle crampsEffect of excessive sodiumIt predisposes a person to hypertension

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Potassium

Functions Helps in regulating the water balance along with sodium Regulates the acid–base balance like sodium Helps in transmitting nerve impulses and contraction of

muscle tissues

SourcesFruits, vegetables, pulses, nuts, flesh food, and whole grains

DeficiencyIt is very rare but may occur in severe malnutrition, chronic alcoholism, surgery, and prolonged infection

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MagnesiumFunctions Helps in maintaining fluid balance along with sodium,

potassium, and calcium Helps in transmission of nerve impulses, muscle

contractions, and regulation of the heart beat Acts as a co-factor in many metabolic reactionsSourcesMilk, cheese, fish, meat, whole grains, pulses, and nutsDeficiencyIt is uncommon and occurs in malnutrition and alcoholism

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Other Mineral Elements

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