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Micronutrients

Micronutrients. What are Macronutrients and Micronutrients? The nutrients can be divided into two major groups – “ Macronutrients” and “ Micronutrients” .

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Micronutrients

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  1. Micronutrients Dr S Nayak

  2. What are Macronutrients and Micronutrients? The nutrients can be divided into two major groups – “Macronutrients” and “Micronutrients”. Macronutrients are those that are needed in large quantities (tens or hundreds of grams) every day. These are: Carbohydrates, protein and fats/oils. Micronutrients are those that are needed in minute quantities (micrograms or at best milligrams). These are vitamins, minerals and trace elements. Dr S Nayak

  3. Vitamins Vitamins are naturally occurring organic substances. Their coenzyme forms are active and are essential in metabolic processes. They serve nearly the same roles in all forms of life. The daily requirement of any vitamin depends on a number of factors and may increase during growth, pregnancy and lactation. They are essential nutrients of humans, and have various roles in the human body Dr S Nayak

  4. Vitamins are either fat-soluble or water-soluble . • Fat soluble vitamins are vitamins A, D, E and K. • Water-soluble vitamins are the B-complex vitamins and vitamin C. • B-complex vitamins are vitamin B1, B2, B6, B12, niacin, folic acid, biotin and pantothenic acid. Dr S Nayak

  5. Soluble vitamins, when taken in excess of body needs, are excreted in urine. • On the other hand, fat-soluble vitamins, when taken in excess, are stored in the body (particularly liver) for use at times when the intake of these vitamins is inadequate. • Most vitamins can be derived from liver, fruits, vegetables, legumes and grains. Dr S Nayak

  6. Vitamin A Preformed retinoid is a collective term for retinol, retinal, and retinoic acid, all of which are biologically active. Recommended Dietary Allowance • Adult: 5000 IU/day • Pregnancy lactation: 4000 IU/day • Infants and children: 3000 IU/day Dr S Nayak

  7. Functions 1.Role of vitamin A in vision Retina of the eye contains two types of cells Rod cells (Vision in dim light) Cone cells (vision in bright light). Rod cells have a photosensitive pigment called rhodopsin, is a conjugated protein made up of opsin and 11-cis retinal Dr S Nayak

  8. 2. Retinoic acid form of vitamin A maintains structural and functional integrity of epithelium 3. Retinol form of vitamin A is required for growth and reproductive function. 4. Retinol is also known to require for the formation of bone and teeth. Deficiency Night blindness Keratomalacia: Dryness of the cornea, corneal epithelium becomes keratinised and opaque and may become softened and ulcerated. Follicular keratosis: Deficiency will affect hair follicles and causes scaly skin Dr S Nayak

  9. Vitamin D Sources Fish liver oils, eggs, milk & butter Sunlight induces synthesis of vit. D in the body from skin cholesterol. Required Dietary Allowance • Children: 400 IU/day • Adults: 400 IU/day • Pregnancy and lactation: 400 IU/day • Vitamin D2 or D3 are not active biologically but converted to active form by hydroxylation [1,25 dihydroxyvitamin D3]. Dr S Nayak

  10. Functions Helps in the mineralization of bones by enhancing absorption of calcium Deficiency The deficiency of vitamin D leads to rickets in children Signs and symptoms are bowlegs, knock knee, pigeon Chest, hypocalcemia and hypophosphatemia Dr S Nayak

  11. Vitamin E Sources Vegetable oils, germinated whole-grain cereals Required Dietary Allowance • Adult male : 30 IU /day • Female : 25 IU/day • Children : 10-20 IU/day Functions 1. Potent physiological antioxidant: Protects membranes with lipids from oxidative damage. Dr S Nayak

  12. 2. Vitamin E, which is present in cell membranes, prevents the destructive non-enzymatic oxidation of polyunsaturated fatty acids (PUFA) by molecular oxygen, and it maintains the membrane integrity. 3.Protects erythrocytes from hemolysis by oxidizing agents (H2O2) 4. Required for normal reproduction in animals. 5. Prevents liver necrosis and muscular dystrophy Deficiency Hemolysis of erythrocytes which may leads to anemia Muscular weakness, fragile RBCs. Dr S Nayak

  13. Vitamin K Phylloquinone, menaquinone and menadione are the three forms of vitamin K Sources • Green leafy vegetables and Tomato, • It is also synthesized by microorganisms in the intestinal tract Functions Required for the maintenance of normal concentration of blood clotting factors. Deficiency Excessive bleeding Dr S Nayak

  14. Vitamin C Sources • Citrus fruits (Orange, lemon), • Tomatoes • Strawberries • Green vegetables • Guava fruit Required Dietary Allowance • Adults: 60 mg/day • Children: 40 mg/day. Dr S Nayak

  15. Functions 1. Collagen synthesis. Vitamin c is involved in the hydroxylation of proline and lysine residues, which are the collagen precursors. 2. It helps in the absorption of iron. 4. Acts as an antioxidant, scavenging the free radicals and reduces the nitrosamine formation. 5. The conversion of dopa to dopamine and dopamine to nor adrenaline requires vitamin C as an activator. Deficiency • Scurvy Spongy gums , loose teeth, fragile blood vessels ,aching swollen joints and delayed wound healing. Dr S Nayak

  16. Thiamin [Vitamin B1] Sources Whole grains (unpolished rice, wheat), legumes (Beans, peas) Meat. Required Dietary Allowance • Children: 1.2 mg/day • Adults: 1.5 mg/day • Pregnancy and lactation – 2.0 mg/day. Functions The coenzyme form of thiamine is Thiamin pyrophosphate (TPP) Helps to release energy from nutrients supports normal appetite and nerve function TPP is required as coenzyme for Pyruvate dehydrogenase complex, α-ketoglutarate dehydrogenase complex, Transketolase etc. Dr S Nayak

  17. Deficiency Cause:alcoholism and malnutrition The overall picture of this vitamin deficiency including neurological, cardiovascular and gastrointestinal disorders is referred to as Beriberi Beriberi is of four types • Dry beriberi (peripheral neuritis) • Wet beriberi (cardiac manifestation) • Cerebral beriberi (Wernicke-Korsakoff’s syndrome) • Infantile beriberi Dr S Nayak

  18. Riboflavin[B2] Sources • Animal liver, yeast, green leafy vegetables, milk & eggs Required Dietary Allowance • Adults: 2.0 mg/day • Children: 1.2 mg/day • Pregnancy and lactation: 2.0 mg/day The riboflavin has two coenzyme forms they are flavin mononucleotide (FMN). Flavin adenine dinucleotide (FAD) Some enzymes have FMN and FAD as their integral part. Such enzymes are called flavoproteins Dr S Nayak

  19. Functions Helps release energy from nutrients; supports health • FMN is required for: 1. L-amino acid oxidase 2. Cytochrome C reductase. • FAD is required as coenzyme for: 1. Succinate dehydrogenase, 2. Pyruvate dehydrogenase complex, 3. α -ketoglutarate dehydrogenase complex, 4. Xanthine oxidase. Dr S Nayak

  20. Deficiency seen in: Malabsorption, malnutrition, and chronic alcoholism Ariboflavinosis • It is the medical condition caused by deficiency of riboflavin. It is often associated with protein energy malnutrition and alcoholism. Characterized by: • Glossitis (Magenta colored tongue) • Cheilosis (Fissuring of the lips) • Fissuring at the corners of mouth, • Seborrheic dermatitis, corneal vascularization are the symptoms of riboflavin deficiency. Dr S Nayak

  21. Niacin [B3] Sources • Lean meats (liver) • Legumes, peanuts (ground nuts) • Green vegetables • Whole grains. • Amino acid tryptophan can be converted to the coenzyme NAD. • About 60 mg of tryptophan yields 1 mg of niacin. Required Dietary Allowance • Adults: 16-20 mg/day. • Children: 9-16 mg/day • Infants: 5-8 mg/day Dr S Nayak

  22. The coenzyme forms of niacin are Nicotinamide Adenine Dinucleotide (NAD) Nicotinamide Adenine Dinucleotide Phosphate (NADP). Functions Helps release energy from nutrients; supports skin, nervous and digestive systems NAD is required as a coenzyme for PDH complex, α-ketoglutarate dehydrogenase complex to mediate the reactions. NADP is required for glucose-6-phosphate dehydrogenase and 6-phosphate gluconate dehydrogenase mediated reactions. Deficiency • Pellagra whichInvolves skin, gastrointestinal tract and central nervous system. Dr S Nayak

  23. Pyridoxine [B6] Sources • Whole grains, • Poultry fish • Potatoes • Organ meats, • Eggs • Legumes. Required Dietary Allowance • Adults: 2.2 mg/day • Children: 1.2 mg/day • Infants: 3.0 mg/day Dr S Nayak

  24. Functions Helps to make red blood cells Helps in amino acid and fatty acid metabolism • Coenzyme form of pyridoxine is pyridoxal phosphate (PLP) • PLP is required as coenzyme for the enzymes like • Transaminases, Decarboxylases, • Kynureninase, Cystathionine α-synthase, • Cystathionine gamma-lyase and ALA synthase. Deficiency • Hypochromic microcytic anemia • Glossitis • Pigmented scaly dermatitis similar to pellagra Dr S Nayak

  25. Biotin [B7] Sources • Egg yolk • Organ meats (liver, kidney) • Milk • Legumes • Nuts Required Dietary Allowance • Adults: 0.3 mg/day. • The intestinal bacteria also synthesize biotin to some extent. Dr S Nayak

  26. Functions Biotin itself functions as coenzyme in the reactions involving fixation of CO2. Helps release energy from carbohydrates; aids in fat synthesis •  Pyruvate carboxylase • Propionyl CoA carboxylase • Acetyl CoA carboxylase Dr S Nayak

  27. Pantothenic acid [B5] Sources • Eggs, Animal liver,Meat , Milk, Vegetables and Grains. Required Dietary Allowance • Adults: 5-10 mg/day • Children: 4-5 mg/day • Infants: 1-2 mg/day Conzyme form: Coenzyme A (CoASH): Required for • Pyruvate dehydrogenase complex • α-ketoglutarate DH complex • Thiokinase  • Thiolase Dr S Nayak

  28. Folic acid Sources • Fresh green, Vegetables, Liver, Whole grains, Meat Legumes. Required Dietary Allowance • Children - 300 µg/day • Adults - 400 µg/day • Pregnancy and lactation - 800 µg/day • The coenzyme form of folic acid is tetrahydro folic acid [THF] (FH4) is the active form. The THF is a carrier of single carbon and it is involved in single carbon transfer reactions Dr S Nayak

  29. Helps in the formation of DNA and new blood cells including red blood cells Deficiency • Megaloblastic anemia The deficiency of folate leads to impairment of the methionine synthase reaction due to which purine ring synthesis is impaired. The impaired synthesis of DNA prevents cell division and formation of the nucleus of new red blood cells. • Growth failure. Dr S Nayak

  30. Vitamin B12 or cobalamin Sources Liver,Meat, Fish, Eggs and Milk. Human beings get small amount of vitamin B12 from their intestinal flora. Required Dietary Allowance • Children: 2 µg/day • Adults: 3 µ g/day • Pregnancy and lactation: 4 µg/day. Active form of Vitamin B12 • Methylcobalamin and Deoxyadenosylcobalamin a Dr S Nayak

  31. Functions • Vitamin B12 along with folic acid is required for the development of red blood cells beyond megaloblastic stage. • It acts as coenzyme for the mutase enzyme which converts methyl malonyl CoA into succinyl CoA. • Methylcobalamin is required in the conversion of homocysteine to methionine • It is involved in the conversion of ribonucleotides to deoxyribonucleotide. Dr S Nayak

  32. Deficiency Cause: malabsorption. Pernicious anemia is caused by a deficiency of intrinsic factor, which leads to impaired absorption of cobalamin. • Megaloblastic anemia, • Glossitis and inflammation of mouth, • Methyl malonic aciduria. Dr S Nayak

  33. Minerals Minerals are vital to physical and mental development. They also help protect the body against infections. Meat, fish, milk, cheese, green leafy vegetables and legumes provide most of the minerals needed by the body. Dr S Nayak

  34. Minerals Minerals are inorganic chemical elements present throughout the body in varying amounts. Like the vitamins, they cannot be synthesized in the body and must be taken with food. Minerals act as co-factors of enzymes for metabolism. Minerals form part of the structure of body tissues, such as bones, teeth and nails, blood, nerves and muscles. Dr S Nayak

  35. Calcium Functions • Mineralization of bones and teeth • Regulator of many of the body’s biochemical processes • Involved in blood clotting • Involved in muscle contraction and relaxation • Nerve function • blood pressure and immune defenses • Activates pancreatic lipase in the digestion of fats • Serves as a second messenger in the action of hormones like adrenaline. Serum ionic calcium level is maintained by vitamin D and hormones like parathyroid hormone (PTH) and calcitonin. Dr S Nayak

  36. Action of Vitamin D a. Increases the absorption of calcium (and phosphate) from the small intestine b. Causes bone resorption. Action of PTH on Kidney and Bone 1. PTH increases the activity of 1 α-hydroxylase in kidney, which increases the synthesis of 1-25-dihydroxy vitamin D3 and this in turn enhance the absorption of calcium from intestine. 2. It increases the reabsorption of calcium from glomerular filtrate in kidneys. 3. It causes the resorption of calcium from bone. The above process helps maintain normal calcium level Dr S Nayak

  37. Hypocalcemia This provokes a characteristic hyper excitable state of the nerves and muscles called tetany. Symptoms are: • Numbness of extremities • Emotional irritability • Tightness and spasm of muscles. – Hypocalcaemia also occurs in hypoparathyroidism, rickets, osteomalacia, pancreatitis, etc. Hypercalcemia Occurs in hyperparathyroidism and hypervitaminosis D. Dr S Nayak

  38. Phosphorous Functions • Mineralization of bones and teeth • Part of every cell • Used in energy transfer and maintenance of acid-base Balance • Helps in the formation of compounds like nucleic acids,nucleotides like ATP, GTP, ADP • It is also required in energy metabolism, synthesis of phospholipids Dr S Nayak

  39. Hypophosphatemia • Rickets • Hyperparathyroidism Clinical symptoms are muscle pain and weakness with respiratory failure and decreased myocardial output Hyperphosphatemia • Seen in hypoparathyroidism • Hypervitaminosis D • Renal failure. Elevated phosphate may cause a decrease in serum concentration. Therefore it may lead to tetany and seizures Dr S Nayak

  40. Sodium Sodium (Na+) is the major cation of the extracellular fluid Functions • Maintains normal fluid and electrolyte balance • Assists nerve impulse initiation and muscle contraction • Helps in the active transport of glucose, galactose and • amino acids across intestinal mucosa and for Na+/K+ ATPase. Hyponatremia Causes • Kidney failure and defect in adrenal cortex • Vomiting and diarrhea Dr S Nayak

  41. Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) Hypernatremia Causes: Hyperactivity of adrenal cortex When water loss exceeds sodium loss, as occurs with Dehydration. Clinical symptoms: high blood pressure, fluid retention and swelling Dr S Nayak

  42. Potassium Most important cation of intracellular fluid Functions • Intracellular K+ is essential for a number of enzyme- mediated reactions such as pyruvate kinase, glycogen synthesis and protein synthesis • The extracellular potassium is important for its influence cardiac muscle Hypokalemia and Hyperkalemia Renal causes Dr S Nayak

  43. Chloride Functions Maintains normal fluid and electrolyte balance It is involved in maintaining osmotic pressure Hypochloremia: Metabolic alkalosis Vomiting diarrhea, diuretics and gastric suction Hyperchloremia :Metabolic acidosis Dehydration, decreased renal blood flow, medications ammonium chloride and Hyperparathyroidism Dr S Nayak

  44. Magnesium Magnesium (Mg2+) is the major intracellular cation Functions • It is an essential activator of many enzymes especially those involving transfer of phosphate groups from ATP. • Examples are hexokinase and phospho­fructokinase. • It also activates a number of enzymes like – enolase, – glucose-6-P dehydrogenase, – pyruvate carboxylase, – thiokinase, – Glucose 6 Phosphogluconatedehydrogenase. Dr S Nayak

  45. Iron Functions • Iron is necessary for the synthesis of certain proteins • Iron containing proteins in the body are of two types: • Heme proteins (Hemoglobin, myoglobin, catalase and cytochrome) and non-heme proteins (ferritin, transferrin, aconitase and sucinate dehydrogenase). • Essential in the formation of blood • Involved in the transport and storage of oxygen in the blood • It is a cofactor bound to several non-heme enzymes Required for the proper functioning of cells Dr S Nayak

  46. Ferritin is the storage form of iron and transferrin is the transport form Deficiency Hypochromic microcytic anemia (microcytic RBC of reduced size). Causes: haemorrhage, malabsorption Iron overload Haemosiderosis and haemochromatosis Dr S Nayak

  47. Copper Functions A need for copper is linked to its functional role in several copper containing enzymes. 1. Ceruloplasmin 2. Cytochromeoxidase 3. Dopamine-oxidase of catecholamine synthetic pathway. 4. Monoamine oxidase and diamineoxidase. 5. Cytoplasmic superoxide dismutase 6. Lysyloxidase involved in cross-linking process in the conversion of tropocollagen to collagen. 7. Tyrosinase of melanin synthetic pathway is a Cu dependent enzyme. Dr S Nayak

  48. Deficiency Hypochromic microcytic anemia Wilson’s disease or Hepatolenticular degeneration It is a fatal inherited disease. Blood copper level decreases. There is an excessive storage of copper in the liver, kidney, brain and cornea Menkes syndrome or Kinky-hair disease It is a rare X-linked recessive disorder Both serum copper and ceruloplasmin and liver copper content are reduced. Depigmentation of the skin and hair Dr S Nayak

  49. Zinc Essential for normal growth, development and reproduction It is required as an activator ion for: • Carbonic anhydrase • Alkaline phosphatase • Liver alcohol dehydrogenase • Carboxyl peptidase A • DNA polymerase • Cytosolic superoxide dismutase Deficiency Dwarfism Acrodermatitis enteropathica: autosomal recessive disorder Dr S Nayak

  50. Manganese Manganese acts as a cofactor or an activator for several enzymes • Acetyl CoA carboxylase • Mitochondrial superoxide dismutase • Arginase • 6 Phosphate-gluconate dehydrogenase • Squalene synthetase • Isocitrate dehydrogenase • Glutamine synthetase • Kinases Dr S Nayak

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