BASIC KNOWLEDGE OF IMPORTANT NUTRIENTS
Nutrients are the constituents in food that must be supplied to the body in suitable amounts. These include carbohydrates, fats, proteins, minerals and vitamins.
Carbohydrates are sugars or polymers of sugars such as starch, that can be hydrolyzed to simple sugars by the action of digestive enzymes or by heating with dilute acids.
Carbohydrates are classified as monosaccharides or simple sugars (glucose, fructose), disaccharides or double sugars (sucrose, lactose) and polysaccharides which include many molecules of simple sugars (starches, dextrins).
The body uses carbohydrate as a source of energy. One gm of carbohydrate provides 4 kilocalories.
They are the major source of energy for muscular work.
The main source of energy for the central nervous system is glucose.
The body mainly uses carbohydrate as the source of energy, thus sparing the tissue protein breakdown for energy purpose. This is called 'protein sparing action of carbohydrates'.
In the liver, carbohydrates have special functions to perform. They include detoxifying action and a regulating influence on protein and fat metabolism.
The heart muscle mainly uses glucose as a source of energy.
Excess of calories is stored in the form of fat in the adipose tissue.
Consumption of indigestible polysaccharides or fibre prevents constipation and reduces the incidence of heart diseases, diabetes mellitus and colon cancer.
RICH SOURCES
Sugar, jaggery, 85 - 99
Cereals and millets 63 - 79
Dried fruits 67 - 77
GOOD SOURCES
Pulses 56 - 60
Milk powder , full fat 38 - 39
Milk powder, skimmed 54 - 55
Roots and tubers 22 - 39
FAIR SOURCES
Fresh fruits 10 - 25
Milk 4
Nuts and oil seeds 10 - 25
The term lipid or fat is applied to a group of naturally occurring substances characterised by their insolubility in water. The lipids present in the diet of animal and human body includes triglycerides, phospholipids and cholesterol.
Fats are a concentrated source of energy. One gram of fat provides 9 calories.
Fat is essential for the absorption of fat soluble vitamins like vitamin A, D, E and K.
Fats improve the palatability and gives a satiety value (ie) feeling of fullness in the stomach.
Fats are deposited in adipose tissue and thus serve as a reserve source of energy during starvation and illness.
They protect vital organs in the body by forming a lining on top.
They act as insulators against heat and cold.
They are the essential constituent of the membrane of every cell.
Phospholipids are present in the plasma in combination with proteins as lipoproteins which are involved in the transport of fat and cholesterol.
Phospholipids are present in large amounts in the nervous system and essential for its function.
Cholesterol serves as a precursor for the formation of bile acids.
FOOD FAT%
RICH SOURCES
Pure oils and fats 100
Ghee and vanaspathi 100
Butter 80-81
GOOD SOURCES
Nuts and oil seeds 40-60
Milk powder, fullfat 26
Eggs 14
Meat and fish 10-15
FAIR SOURCES
Milk, cow's 4
Milk, buffalo 7
Pulses (whole) 3-5
Cereals and millets 2-3
Dietary protein performs all three functions of nutrients .It is needed for growth, maintenance, and repair of body tissues. It regulates key processes within the body and only excess protein can be used as a source of energy.
1 . Proteins are required for the growth and maintenance of tissues.
It is needed for the formation of essential body compounds.
It regulates water balance in the body.
It helps in the transport of nutrients.
It is required for the maintenance of appropriate pH.
It is also a source of energy. One gram of protein provides 4 calories.
It fights the body against diseases.
It helps in detoxifying action.
FOODS PROTEIN%
RICH SOURCES
Meat, fish and liver 18-20
Eggs 14
Milk powder, full fat 26
Cheese 18-20
Pulses, dry 18-24
Nuts and oilseeds 18-26
Soyabean 35-40
GOOD SOURCES
Cereals and millets 6-12
Calcium makes up between 1.5-2% of body weight. Almost 99% of this calcium is found in the hard tissues of the body, namely the bones and teeth.
It is essential for the formation of bones and teeth.
It is essential for clotting of blood.
It regulates the permeability of capillary walls.
It is essential for the contraction of heart and muscle.
It regulates the excitability of nerve fibres and nerve centres.
It acts as an activator for the enzymes present in the gastric juice.
Food stuffs Calcium (mg/100g)
Rich sources
Milk powder, sesame seeds with 1.20-1.45
husk and small dried fish
Good sources
Ragi, milk and green leafy
vegetables and small fish eaten
with bone 0.10-0.33
Phosphorus constitutes approximately 1% of the weight of the human body, Upto 90% of this is found within calcium phosphate crystals in the bones and teeth.
It is necessary for the formation of bones and teeth.
It is essential for carbohydrate metabolism.
It is a constituent of certain co-enzymes.
It is an essential constituent of nucleic acids and nucleoproteins which are integral parts of the cell nuclei.
Sources of Phosphorus
Food stuffs Phosphorus (g/100g)
Cereals, Millets, Pulses, nuts
and Oilseeds 0.20 - 0.65
Dried fish 1.2 - 1.3
Milk powder 0.76 - 0.82
Meat, fish and eggs 0.31 - 0.41
Milk 0.09 - 0.11
Most of the iron in the body is found in the blood, but some is present in every cell bound to iron containing enzymes.
It is required for the transport and storage of oxygen in cells & tissues.
It acts as co-factors of enzymes and other proteins.
It is required for the formation of red blood cells.
Food stuffs Iron (mg/l00g)
Rich sources
Sesame seeds, jaggery and
green leafy vegetables. 10-20
Good sources
Cereals and millets 3-8
Liver 7-9
Meat and egg 2-3
Iodine is a constituent of thyroxine, the active principle of the thyroid gland. The thyroid gland plays an important role in energy metabolism and in the growth of the body.
Iodine is present only in small amounts in common foods, the quantity of iodine present depending on the iodine content of the soil. Iodised salt and seafish are good sources of iodine.
Vitamins may be defined as organic compounds occurring in small quantities in the different natural foods and necessary for the growth and maintenance of good health in human beings.
Vitamin A plays a critical role in vision in dim light.
Vitamin A is essential for the integrity of the mucous secreting cells of epithelial tissues.
It is essential for normal bone formation.
Vitamin A deficiency causes degeneration of the myelin sheath.
Vitamin A is essential for the synthesis of mucoproteins and glycoproteins.
It is essential for normal reproduction.
Vitamin A is present only in foods of animal origin, such as liver, eggs, milk and fatty fish. All plant foods contain only carotenoids which is converted to vitamin A in the body .Papaya, mango, carrots, green leafy vegetables and other yellow, orange coloured fruits and vegetables are good sources of b-carotene.
Vitamin D promotes the absorption of calcium and phosphate from the small intestines.
This also acts on the bones directly promoting calcification.
It regulates the concentration of calcium in blood plasma.
The good sources of vitamin D includes sunlight, fish liver oils, butter, cheese, ghee and milk.
It is essential for normal reproduction in man.
It is required for the normal functioning of the immune system.
It is an antioxidant, which reduces the incidence of heart diseases.
Vegetable oils and fats, nuts and oilseeds and whole grams are the richest natural sources of vitamin E.
Vitamin K is essential for blood coagulation. It is required for the synthesis of various substances needed for blood clotting.
The concentration of vitamin K is highest in dark green leafy vegetables, but it is also found in liver, pulses, cereals and some tubers.
Vitamin C is essential for
Formation of collagens and intercellular cement substances.
Absorption of iron and incorporation of plasma iron in ferritin.
Bone formation.
Adrenal cortex function.
Neuro transmitter synthesis.
Aids in calcium absorption.
Drug detoxification.
Activation of hormones.
The rich sources of vitamin C includes amla, guava and other citrus fruits. Good sources include green leafy vegetables and fruits like papaya and tomato.
Thiamine is essential for growth.
It is essential for maintaining the nerves in normal condition.
It plays an important role in carbohydrate metabolism.
Diets based on whole wheat, millets, raw hand pounded rice or parboiled rice usually supplies thiamine in the diet. Organ meats, pork, liver, eggs and whole grams are fair sources of thiamine.
Riboflavin is involved in the regulatory functions of some hormones involved in carbohydrate metabolism.
The retina contains free riboflavin, which is converted by light to a compound involved in stimulation of the optic nerve.
Riboflavin plays, an important role in many enzyme systems involved in the metabolism of carbohydrates, fats and proteins.
It is involved in the formation of red blood cells in the bone marrow.
Rich sources of riboflavin include milk and milk products, eggs, liver, and dried yeast. Good sources are green leafy vegetables, whole cereals and millets, meat and fish. Fair sources include milled cereals, cereal products and roots and tubers.
Nicotinic acid is essential for the normal functioning of the skin, intestinal tract and the nervous system.
Nicotinic acid is a component of two coenzymes NAD and NADP, which take part in several enzymatic reactions.
The rich sources of niacin are groundnuts, dried yeast and liver. Good sources are whole cereals, legumes, meat and fish. The fair sources include milled cereals, maize, milk and eggs.
Pyridoxine like other vitamins functions as a co-enzyme.
It is essential for growth of infants and prevention of macrocytic anemia.
Meat, pulses,wheat and dried yeast are good sources while green leafy vegetables and other cereals are fair sources of this vitamin.
It is essential for the maturation of red blood cells.
It is required for the normal growth and division of all cells.
It plays a role in the metabolism of some amino acids.
It prevents megaloblastic anaemia.
Fresh green leafy vegetables, yeast, liver and eggs are rich sources of this vitamin. Cereals, pulses, nuts, oilseeds and other vegetables like ladies finger and cluster beans are good sources of this vitamin.
It promotes the maturation of erythroid cells.
It is involved in biochemical-processes essential for DNA synthesis and division of cells.
It is required for the synthesis of myelin, the white sheath that covers the nerve fibers.
It stimulates appetite and improves the general health of the patient.
It cures the neurological symptoms of pernicious anemia.
Vitamin B(12) is normally present only in animal foods like liver, egg,
mutton and milk.
Functions
It is involved in the synthesis of amino acids, B12 and hemoglobin.
The best sources of pantothenic acid are liver, kidney, egg yolk, yeast and fresh vegetables. Milk and meat are fairly good sources.
Biotin takes part as a coenzyme in several metabolic functions of carbohydrate and lipid metabolism.
Liver, kidney and yeast extracts are good sources. Pulses, nuts and chocolate are fair sources of this vitamin.
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