What is Nutrition?
Nutrition is defined as the science of food and its relationship to health. It is considered primarily with the part played by nutrients in body growth, development and maintenance.
Good nutrition means “maintaining a nutritional status that enables us to grow well and enjoy good health”
Nutrients
Nutrients are organic and inorganic complexes contained in food. They are of two types
(i) Macro Nutrients: Proteins, fats and carbohydrates are called as macro nutrients because they form the main bulk of the food
Proteins- 7-15%
Fats- 10-30%
Carbohydrates- 65-80%
(ii) Micro Nutrients: Vitamins and minerals. They are required in small amounts.
Proteins
Proteins are complex organic nitrogenous compounds. They are composed of carbon, hydrogen, oxygen, nitrogen and sulfur. Proteins are made of smaller units called as amino acids. There are essential and non-essential amino acids. Essential amino acids have important biological functions. New tissues cannot be formed unless all the essential amino acids are present in the diet.
NOTE: Essential amino acids cannot be synthesized by the human body and should be supplied along with diet. Whereas non-essential amino acids are synthesized in human body and need not require any essential supplements.
Sources:
Anima source: Milk, meat, eggs, cheese fish and fowl.
Vegetable source: Pulses, cereals, beans, nuts, oil-seed cakes.
Functions:
Daily requirements:
The daily average requirement of proteins is 75grams.
Deficiency:
Fats
Fats are solids at 20 degrees Celsius. They are called as oils if they are liquids at room temperature. Fats and oils are rich energy sources. Fats yield fatty acids and glycerol on hydrolysis. There are saturated fatty acids and unsaturated fatty acids. Essential fatty acids are those that cannot be synthesized by humans. The most important essential fatty acid is linolenic acid.
Sources:
Animal fats: Ghee, butter, milk, cheese, egg and fat of meat and fish
Vegetable fats: Groundnut, mustard, sesame, coconut. They are the sources of vegetable oils.
Functions:
Fats and Disease:
Requirements:
The average daily requirement of fats-55grams
Carbohydrates:
The main source of energy providing constituent. Carbohydrates provide 50% energy and heat required by the body. They are stored in liver as glycogen.
Sources:
Starch- Cereals, roots and tubers
Sugars- Monosaccharides(glucose, fructose and galactose), disaccharides(sucrose, lactose and maltose)
Dietary fibers- Vegetables, fruits and grains.
Functions:
Deficiency:
Requirements:
The average daily requirement is 400grams.
Vitamins:
Vitamins are a class of organic compounds categorized as essential nutrients. They are required by the body in very small amounts. Vitamins are divided into two groups
Vitamin-A
Source:
Animal foods - Liver, eggs, butter, cheese, whole milk, fish and meat. Fish liver oils are the richest source of vitamin A
Plant foods- Spinach and amaranth, papaya, mango, carrots etc.
Functions:
Deficiency:
Daily requirement:
5000 I.U (International units)
Toxicity
Nausea, vomiting, anorexia, sleep disorders. Skin desquamatization, enlarged liver, papillar oedema.
Vitamin D
The important forms of Vitamin D in man are calciferol(Vitamin D2) and chole calciferol(Vitamin D3)
Sources:
Sunlight- Vitamin D is synthesized by the body by action of ultra violet rays of sunlight on 7-dehydro cholesterol, which is stored in large abundance in skin.
Foods- Liver, egg yolk, butter, cheese, milk, fish fat.
Functions:
Deficiency:
Requirements:
Adults- 2.5micro grams (100IU)
Infants and children- 5.0micro grams (200IU)
Pregnancy and lactation- 10.0micro grams (400IU)
Vitamin E
Vitamin E is the generic name for a group of closely related naturally occurring fat soluble compounds, the tocopherols.
Sources:
Vegetable oils, cotton seed, sunflower seed, egg yolk and butter. Foods rich in poly unsaturated fatty acids are also rich in Vitamin E.
Functions:
This is one group of anti-oxidants that serves to scavenge free radicals formed in the redox reactions(reduction reactions) throughout the body.
Deficiency:
Requirement:
10mg/day
Vitamin K
Vitamin K occurs in at least two major forms, Vitamin K1 and Vitamin K2.
Sources:
Vitamin K1- Fresh green vegetables, Cow’s milk
Vitamin K2- Synthesized by intestinal bacteria
Functions:
The most important function is the synthesis of certain blood coagulation factors.
Deficiency:
Thiamine
Vitamin B1 (Thiamine) is a water soluble vitamin
Source:
Whole grain cereals, wheat, gram, yeast, pulses, oil seeds and nuts.
Meat, fish, eggs, vegetables and fruits (fruits contain smaller amounts)
Functions:
Essential for utilization of carbohydrates. It is involved in direct oxidative pathway of Glucose.
Deficiency:
Beriberi and Wernick’s encephalopathy.
Dry beriberi is characterized by nerve involvement. Wet beriberi is seen in infants between 2 and 4 months of life.
Wernick’s encephalopathy is characterized by opthalmoplegia, polyneuritis, ataxia and mental disorientation.
Requirement:
1.5mg/day
Riboflavin (Vitamin B2)
Sources:
Milk, eggs, liver, kidney and green leafy vegetables.
Meat and fish contain small amounts.
Functions:
Deficiency:
Requirement:
1.5mg/day
Niacin
Sources:
Liver, kidney, meat, poultry, fish, legumes and groundnut.
Functions:
Niacin is essential for the metabolism of carbohydrate, fat and protein. Essential for normal functioning of the skin, intestine and nervous system.
Deficiency:
Requirement:
18mg/day
Pyridoxine (Vitamin B6)
Pyridoxine exists in three forms pyridoxal and pyridoxamine.
Source:
Milk, liver, meat, egg yolk, fish, whole grain cereals, legumes and vegetables.
Functions:
It plays an important role in metabolism of amino acids, fats and carbohydrates.
Deficiency:
Peripheral neuritis
Requirement:
Adults- 2mg/day
Pregnancy and lactation- 2.5mg/day
Folate:
Sources:
Liver, meat, dairy products, eggs, milk, fruits and cereals.
Functions:
Deficiency:
Requirement:
Adults- 100mcg/day
Pregnancy- 300mcg/day
Lactation- 150mcg/day
Children- 100mcg/day
Vitamin B12
Sources:
Liver, kidney, meat, fish, eggs, milk and cheese. Vitamin B12 is not found in foods of vegetable origin. It is also synthesized by bacteria in colon.
Functions:
Vitamin B12 has a separate biochemical role in synthesis of fatty acids and myelin.
It cooperates with folate in synthesis of DNA.
Deficiency:
Requirement:
Adults- 1mcg/day
Pregnancy and lactation- 1.5mcg/day
Infants and children- 0.2mcg/day
Vitamin C
Vitamin C is a water soluble vitamin. It is the most sensitive of all vitamins to heat.
Sources:
Fresh fruits and green leafy vegetables. Germinating pulses contain huge amounts. Amla or gooseberry and guava are the richest sources of Vitamin C
Functions:
Deficiency:
Scurvy- signs of which are swollen and bleeding gums, subcutaneous bruising or bleeding into the skin or joints, delayed wound healing, anemia and weakness.
Requirement:
Adults- 40mg/day
Children- 40mg/day
Infants- 20mg/day
Lactation- 80mg/day
MINERALS
Calcium and Phosphorous
These are the abundant minerals in the body. They make up most of the skeletal structure. Calcium compromises of 1.5 to 2% and phosphorous about 1% of the body weight. They provide rigidity and strength to bone and teeth.
Sources:
Calcium- milk, milk products, eggs and fish
Phosphorous- vegetables
Deficiency:
Requirement:
Calcium- 400-500mg/day
Phosphorous- 1.5mg/day
Magnesium:
It is a constituent of bones and is present in all body cells. Magnesium is essential for the normal metabolism of calcium and potassium.
Sources:
Vegetables
Deficiency:
Irritability, tetany, hyperflexia
Requirement:
200-300mg/day
TRACE ELEMENTS
WHO (World Health Organization) has recognized 14 trace elements, which should be present in human nutrition. These are iron, iodine, fluoride, copper, zinc, cobalt, chromium, manganese, molybdenum, tin, nickel, silicon, selenium and vanadium
Iron
Sources:
Liver, meat, poultry, fish, cereals, green leafy vegetables, legumes, nuts.
Deficiency:
Iodine
Sources:
Seafood, cod liver oil, milk, meat and vegetables.
Deficiency:
Zinc
Sources:
Liver, kidney, green leafy vegetables.
Deficiency:
Selenium, Molybdenum, Vanadium, Strontium
These are cariostatic because they reduce the acid solubility of calcified dental tissues.
Copper
It is widely distributed in nature
Deficiency:
Requirement:
2mcg/day
SO WHAT DID YOU LEARNT?
WHAT IS BALANCED DIET?
A balanced diet contains a variety of foods in such quantities and proportions that the need for energy, amino acids, vitamins, minerals, fats, carbohydrates and other nutrients is adequately met for maintaining health.
In constructing balanced diet, the following principles should be borne in mind:
Nutrition is defined as the science of food and its relationship to health. It is considered primarily with the part played by nutrients in body growth, development and maintenance.
Good nutrition means “maintaining a nutritional status that enables us to grow well and enjoy good health”
Nutrients
Nutrients are organic and inorganic complexes contained in food. They are of two types
(i) Macro Nutrients: Proteins, fats and carbohydrates are called as macro nutrients because they form the main bulk of the food
Proteins- 7-15%
Fats- 10-30%
Carbohydrates- 65-80%
(ii) Micro Nutrients: Vitamins and minerals. They are required in small amounts.
Proteins
Proteins are complex organic nitrogenous compounds. They are composed of carbon, hydrogen, oxygen, nitrogen and sulfur. Proteins are made of smaller units called as amino acids. There are essential and non-essential amino acids. Essential amino acids have important biological functions. New tissues cannot be formed unless all the essential amino acids are present in the diet.
NOTE: Essential amino acids cannot be synthesized by the human body and should be supplied along with diet. Whereas non-essential amino acids are synthesized in human body and need not require any essential supplements.
Sources:
Anima source: Milk, meat, eggs, cheese fish and fowl.
Vegetable source: Pulses, cereals, beans, nuts, oil-seed cakes.
Functions:
- Body building
- Repair and maintenance of body tissues
- Maintenance of osmotic pressure
- Synthesis of certain substances like antibodies, plasma proteins, heamoglobin, enzymes, hormones and coagulation factors.
Daily requirements:
The daily average requirement of proteins is 75grams.
Deficiency:
- Kwashiorkor is the result of protein deficiency
- Delayed eruption and hypoplasia of deciduous teeth
- Cementum deposition is retarded
- Resorption of alveolar bone
Fats
Fats are solids at 20 degrees Celsius. They are called as oils if they are liquids at room temperature. Fats and oils are rich energy sources. Fats yield fatty acids and glycerol on hydrolysis. There are saturated fatty acids and unsaturated fatty acids. Essential fatty acids are those that cannot be synthesized by humans. The most important essential fatty acid is linolenic acid.
Sources:
Animal fats: Ghee, butter, milk, cheese, egg and fat of meat and fish
Vegetable fats: Groundnut, mustard, sesame, coconut. They are the sources of vegetable oils.
Functions:
- They are high energy sources thus provides energy
- Serve as vehicles for fat soluble vitamins
- Fats in body support viscera such as heart, kidney and intestine
- Essential fatty acids are needed for growth, for structural integrity of cell membrane and decreased platelet adhesiveness.
Fats and Disease:
(a) Obesity- A diet rich in
fat can pose a threat to human health by encouraging obesity
(b) Phrenoderma- Deficiency of
essential fatty acids is associated with dry and rough skin.
(c) Coronary heart disease-
High fat intake has been identified as major risk factor for coronary heart
disease
(d) Cancer- Diets high in fat
increase the risk of colon cancer and breast cancer.
Requirements:
The average daily requirement of fats-55grams
Carbohydrates:
The main source of energy providing constituent. Carbohydrates provide 50% energy and heat required by the body. They are stored in liver as glycogen.
Sources:
Starch- Cereals, roots and tubers
Sugars- Monosaccharides(glucose, fructose and galactose), disaccharides(sucrose, lactose and maltose)
Dietary fibers- Vegetables, fruits and grains.
Functions:
- Essential for oxidation of fats
- Essential for synthesis of certain non-essential amino acids
Deficiency:
1.
Marasmus is the result of carbohydrate deficiency
2.
Abnormal fat metabolism
3.
Excess excretion of sodium
4.
Loss of energy and fatigue
Requirements:
The average daily requirement is 400grams.
Vitamins:
Vitamins are a class of organic compounds categorized as essential nutrients. They are required by the body in very small amounts. Vitamins are divided into two groups
- Fat soluble vitamins-vitamins A, D, E and K
- Water soluble vitamins-vitamins of B-group and C
Vitamin-A
Source:
Animal foods - Liver, eggs, butter, cheese, whole milk, fish and meat. Fish liver oils are the richest source of vitamin A
Plant foods- Spinach and amaranth, papaya, mango, carrots etc.
Functions:
- It is indispensable for normal vision
- Necessary for maintaining the integrity and normal functioning of glandular and epithelial tissues which lines intestinal, respiratory and urinary tracts
- It supports growth especially skeletal growth.
Deficiency:
1.
Night blindness
2.
Bitot’s spots
3.
Corneal xerosis
4.
Keratomalacia(softening, drying and ulceration of cornea)
5.
Hyperkeratosis and hyperplasia of gingival tissue
6.
Atrophy of odontoblasts(cells which help in formation of enamel)
7.
Atrophy of salivary glands
Daily requirement:
5000 I.U (International units)
Toxicity
Nausea, vomiting, anorexia, sleep disorders. Skin desquamatization, enlarged liver, papillar oedema.
Vitamin D
The important forms of Vitamin D in man are calciferol(Vitamin D2) and chole calciferol(Vitamin D3)
Sources:
Sunlight- Vitamin D is synthesized by the body by action of ultra violet rays of sunlight on 7-dehydro cholesterol, which is stored in large abundance in skin.
Foods- Liver, egg yolk, butter, cheese, milk, fish fat.
Functions:
- It helps in absorption of calcium
- Used in maintenance of calcium homeostasis and skeletal integrity
Deficiency:
1.
Rickets- observed in young children
2.
Osteomalacia- observed in adults
Requirements:
Adults- 2.5micro grams (100IU)
Infants and children- 5.0micro grams (200IU)
Pregnancy and lactation- 10.0micro grams (400IU)
Vitamin E
Vitamin E is the generic name for a group of closely related naturally occurring fat soluble compounds, the tocopherols.
Sources:
Vegetable oils, cotton seed, sunflower seed, egg yolk and butter. Foods rich in poly unsaturated fatty acids are also rich in Vitamin E.
Functions:
This is one group of anti-oxidants that serves to scavenge free radicals formed in the redox reactions(reduction reactions) throughout the body.
Deficiency:
- Anatomic changes in the nervous system. Ataxia , dysarthria, loss of pain sensation, depressed tendon reflexes.
- Hemolytic and hypoplastic anemia
- Degenerative lesions in skeletal muscles and heart
Requirement:
10mg/day
Vitamin K
Vitamin K occurs in at least two major forms, Vitamin K1 and Vitamin K2.
Sources:
Vitamin K1- Fresh green vegetables, Cow’s milk
Vitamin K2- Synthesized by intestinal bacteria
Functions:
The most important function is the synthesis of certain blood coagulation factors.
Deficiency:
- Prothrombin content of blood is markedly decreased and the blood clotting time is considerably increased.
- Bleeding
Thiamine
Vitamin B1 (Thiamine) is a water soluble vitamin
Source:
Whole grain cereals, wheat, gram, yeast, pulses, oil seeds and nuts.
Meat, fish, eggs, vegetables and fruits (fruits contain smaller amounts)
Functions:
Essential for utilization of carbohydrates. It is involved in direct oxidative pathway of Glucose.
Deficiency:
Beriberi and Wernick’s encephalopathy.
Dry beriberi is characterized by nerve involvement. Wet beriberi is seen in infants between 2 and 4 months of life.
Wernick’s encephalopathy is characterized by opthalmoplegia, polyneuritis, ataxia and mental disorientation.
Requirement:
1.5mg/day
Riboflavin (Vitamin B2)
Sources:
Milk, eggs, liver, kidney and green leafy vegetables.
Meat and fish contain small amounts.
Functions:
- It has a fundamental role in cellular oxidation.
- It is co-factor in a number of enzymes involved with energy metabolism.
Deficiency:
1.
Angular stomatitis
2.
Cheilosis
3.
Glossitis
Requirement:
1.5mg/day
Niacin
Sources:
Liver, kidney, meat, poultry, fish, legumes and groundnut.
Functions:
Niacin is essential for the metabolism of carbohydrate, fat and protein. Essential for normal functioning of the skin, intestine and nervous system.
Deficiency:
- Pellagra
- It is characterized by three D’s- Diarrhoea, Dermatitis and Dementia.
- Glossitis
- Stomatitis
Requirement:
18mg/day
Pyridoxine (Vitamin B6)
Pyridoxine exists in three forms pyridoxal and pyridoxamine.
Source:
Milk, liver, meat, egg yolk, fish, whole grain cereals, legumes and vegetables.
Functions:
It plays an important role in metabolism of amino acids, fats and carbohydrates.
Deficiency:
Peripheral neuritis
Requirement:
Adults- 2mg/day
Pregnancy and lactation- 2.5mg/day
Folate:
Sources:
Liver, meat, dairy products, eggs, milk, fruits and cereals.
Functions:
- Plays a role in synthesis of nucleic acids
- It is also needed for the normal development of blood cells in the marrow
Deficiency:
1.
Megaloblastic anemia
2.
Glossitis
3.
Cheilosis
4.
Gastro-intestinal disturbances
Requirement:
Adults- 100mcg/day
Pregnancy- 300mcg/day
Lactation- 150mcg/day
Children- 100mcg/day
Vitamin B12
Sources:
Liver, kidney, meat, fish, eggs, milk and cheese. Vitamin B12 is not found in foods of vegetable origin. It is also synthesized by bacteria in colon.
Functions:
Vitamin B12 has a separate biochemical role in synthesis of fatty acids and myelin.
It cooperates with folate in synthesis of DNA.
Deficiency:
- Megaloblastic anemia
- Demyelinating neurological lesions in the spinal cord
- Infertility
Requirement:
Adults- 1mcg/day
Pregnancy and lactation- 1.5mcg/day
Infants and children- 0.2mcg/day
Vitamin C
Vitamin C is a water soluble vitamin. It is the most sensitive of all vitamins to heat.
Sources:
Fresh fruits and green leafy vegetables. Germinating pulses contain huge amounts. Amla or gooseberry and guava are the richest sources of Vitamin C
Functions:
- Vitamin C has an important role to play in tissue oxidation
- It is needed for the formation of collagen
Deficiency:
Scurvy- signs of which are swollen and bleeding gums, subcutaneous bruising or bleeding into the skin or joints, delayed wound healing, anemia and weakness.
Requirement:
Adults- 40mg/day
Children- 40mg/day
Infants- 20mg/day
Lactation- 80mg/day
MINERALS
Calcium and Phosphorous
These are the abundant minerals in the body. They make up most of the skeletal structure. Calcium compromises of 1.5 to 2% and phosphorous about 1% of the body weight. They provide rigidity and strength to bone and teeth.
Sources:
Calcium- milk, milk products, eggs and fish
Phosphorous- vegetables
Deficiency:
- Altered calcification
- Increased dental caries
- Reduction in alveolar bone formation
Requirement:
Calcium- 400-500mg/day
Phosphorous- 1.5mg/day
Magnesium:
It is a constituent of bones and is present in all body cells. Magnesium is essential for the normal metabolism of calcium and potassium.
Sources:
Vegetables
Deficiency:
Irritability, tetany, hyperflexia
Requirement:
200-300mg/day
TRACE ELEMENTS
WHO (World Health Organization) has recognized 14 trace elements, which should be present in human nutrition. These are iron, iodine, fluoride, copper, zinc, cobalt, chromium, manganese, molybdenum, tin, nickel, silicon, selenium and vanadium
Iron
Sources:
Liver, meat, poultry, fish, cereals, green leafy vegetables, legumes, nuts.
Deficiency:
- Gingivitis
- Glossitis
- Stomatitis
- Delayed wound healing
Iodine
Sources:
Seafood, cod liver oil, milk, meat and vegetables.
Deficiency:
- Hypothyroidism
- Small jaw
- Retarded eruption of teeth
- Root resorption
Zinc
Sources:
Liver, kidney, green leafy vegetables.
Deficiency:
- Thickening of skin
- Loss of hair
Selenium, Molybdenum, Vanadium, Strontium
These are cariostatic because they reduce the acid solubility of calcified dental tissues.
Copper
It is widely distributed in nature
Deficiency:
- Neutropenia
- Hypocupremia occurs in patients with nephrosis, Wilson’s disease
Requirement:
2mcg/day
SO WHAT DID YOU LEARNT?
WHAT IS BALANCED DIET?
A balanced diet contains a variety of foods in such quantities and proportions that the need for energy, amino acids, vitamins, minerals, fats, carbohydrates and other nutrients is adequately met for maintaining health.
In constructing balanced diet, the following principles should be borne in mind:
- The daily requirement of protein should be met. This amounts to 15-20% of daily energy intake.
- Fat requirement should be limited to 20-3-% of daily energy intake
- Carbohydrates rich in natural fiber should constitute the remaining food energy
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