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Biochemical principles of nutrition


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Title: Biochemical principles of nutrition

Biochemical principles of nutrition
  • Nutrition may be defined as the science of
    food and its relationship to health. It is
    concerned primarily with the part played by
    nutrients in body growth, development and
    maintenance. The word nutrient or "food factor"
    is used for specific dietary constituents such as
    proteins, vitamins and minerals. Dietetics is
    the practical application of the principles of
    nutrition it includes the planning of meals
    for the well and the sick. Good nutrition means
    "maintaining a nutritional status that enables us
    to grow well and enjoy good health".

  • In various historical times structure of
    nutrition and character of a nutrition changed
    depending on
  • development of industrial forces of a society,
  • climate-geographical conditions,
  • direction of economic activity and so on.
  • The character of nutrition of the population
    was formed gradually depending on an economic and
    cultural level of development of the country, in
    view of national customs and features.
  • Through centuries, food has been recognized as
    important for human beings in health and disease.

  • Good nutrition is a basic component of health.
    The relation of nutrition to health may be seen
    from the following view points
  • Growth and development Good nutrition is
    essential for the attainment of normal growth and
    development. Not only physical growth and
    development, but also the intellectual
    development, learning and behaviour are affected
    by malnutrition.
  • Specific deficiency Malnutrition is directly
    responsible for certain specific nutritional
    deficiency diseases. Good nutrition therefore
    is essential for the prevention of specific
    nutritional deficiency diseases and promotion of
  • Resistance to infection Infection, in turn, may
    aggravate malnutrition by affecting the food
    intake, absorption and metabolism.
  • Mortality and morbidity The indirect effects of
    malnutrition on the community are even more
    striking - a high general death rate, high infant
    mortality rate, high sickness rate and a lower
    Expectation of life.

'You are what you eat', some people say. If you
eat rubbishy food, you can't really expect to
grow up strong and healthy.                    
But if you eat good-quality food, you've a good
chance of doing so. That's just commonsense
  • Main rules of healthy nutritional
  • Eating fruits, vegetables, and grain products
    that contain fiber may help prevent heart disease
  • Limiting the amount of saturated fat and
    cholesterol in your diet may reduce your risk of
    heart disease
  • Limiting the amount of total fat you eat may help
    reduce your risk for cancer
  • Eating fiber-containing grain products, fruits,
    and vegetables may help prevent cancer
  • Eating fruits and vegetables that are "low in
    fat" and "good sources" of dietary fiber, vitamin
    A, or vitamin C may help prevent cancer

Nutrition as a science can be regarded as the
study of six main categories of food components

  • Water
  • Water is necessary to make up the loss caused
    by its excretion in breath, sweat, urine, faces,
    and also to renew all the various fluids and
    solid organs of the body.
  • It is estimated that about 2 liters of water
    enters the body daily as such or as a part of
    cooked food, beverages etc. Out of which 1.37 -
    1.81 liters is excreted daily in urine, sweat
  • Some important uses of water are
  • - As a solvent for transportation of nutrients in
    the body.
  • - It helps regulating body temperature
    through evaporation from lungs and skin.
  • - As an aid in removing wastes of metabolism in
    the urine.
  • - As an aid in functions like osmosis.

Diseases, that is direct or mediate related with
a nutrition
4. Disease, which are transferred by a
nutritional way (some infections diseases and
intestinal worms, alimentary poisonings).
  • 1. Alimentary disease, illness caused by
    deficiency or surplus of components of nutrition.

3. Disease of multifactor nature that very much
frequently develops on a background of genetic
predilection, for example, atherosclerosis, gout,
idiopathic hypertension, etc.
2. The secondary illnesses of insufficiency or
excessive nutrition, which is developed as
complication on a background of wearisome
illnesses (surgical, infectious, oncology and
5. Alimentary intolerance - atypical reaction to
nutrition, for example alimentary allergy,

Function of nutrition
Provision of energy
  • Body building and repair

Maintenance and regulation of tissue functions
  • Classification by predominant functions
  • Energy-giving foods. These constitute fats and
    carbohydrates. They are also called protein
    sparer. Proteins also produce energy to some
    extent. Cereals, roots and tubers, dried fruits,
    sugars and fats belong to this group. They supply
    heat and energy to the body.
  • Body building foods. These are foods rich in
    proteins, mineral salts and water. Milk, meat,
    fish, pulses, oilseeds and nuts fall in this
  • Protective foods. These constitute inorganic
    salts, vitamins and minerals. They include
    proteins and water. Milk, eggs, liver, green
    leafy vegetables and fruits are included in this
    group. They build our bones, teeth, muscles, soft
    tissues, blood and other body fluids. They
    provide material for repair in the body as wear
    and tear goes on constant.

  • 2. Classification by origin
  • Foods of animal origin
  • Foods of vegetable origin
  • 3. Classification by chemical composition
  • Proteins
  • Fats
  • Carbohydrates
  • Vitamins
  • Minerals
  • 4. Classification by nutritive value
  • Cereals and millets
  • Pulses (legumes)
  • Vegetables
  • Nuts and oilseeds
  • Fruits
  • Animal foods
  • Fats and oils
  • Sugar and jaggery
  • Condiments and spices
  • Miscellaneous foods


Balanced diet is one, which will meet a person's
caloric need and contain all nutrients,
particularly proteins, and vitamins. In addition,
the food should satisfy the taste and desire of a
person and should have enough roughage to promote
the peristalsis. Balanced diet should have 50-60
carbohydrates 30-35 fats and 10-15 proteins
with necessary vitamins and minerals. A balanced
diet must contain foods from the above three
Importance of the main components of food in
nutrition of the man
  • Nutrients are organic and inorganic complexes
    contained in food. There are about 50 different
    nutrients which are normally supplied through the
    foods we eat. Each nutrient has specific
    functions in the body. Most natural foods contain
    more than one nutrient. These may be divided into
  • (i) Macronutrients These are proteins, fats and
    carbohydrates which are often called
    "proximate principles" because they form the
    main bulk of food.
  • (ii) Micronutrients These are vitamins and
    minerals. They are called micronutrients because
    they are required in small amounts which may vary
    from a fraction of a milligram to several grams.

PROTEINSThe word "protein" means that which is
of first importance. Indeed they are of the
greatest importance in human nutrition. Proteins
are composed of carbon, hydrogen, oxygen,
nitrogen and sulphur in varying amounts. Some
proteins also contain phosphorus and iron and
occasionally other elements. Proteins differ from
carbohydrate and fat in the respect that they
contain nitrogen. Proteins are made up of simpler
substances, called amino acids. These are the
building blocks of proteinSome 22 amino acids
are stated to be needed by the human body, out of
which eight are called "essential".

  • Proteins are needed by the body
  • For growth and development They furnish the
    building material, i.e. the amino acids from
    which the body proteins are synthesized.
  • For repair of body tissues and their maintenance
    It has been shown that the body proteins
    are constantly being broken down they have to
    be replaced for which fresh protein
    intake is required.
  • For synthesis of antibodies, enzymes and
    hormones Antibodies, enzymes and hormones
    contain protein. The body requires protein
    to produce them.
  • Proteins can also furnish energy to the body, but
    generally the body depends for its energy on
    carbohydrates and fats rather than proteins.

Sources of protein
Plant sources
Animal sources
  • Protein requirements
  • Doctors recommended 1,0 g. protein/kg body
    weight for an adult.
  • Daily allowances recommended by experts of the
    World Health Organization (Geneva, 1976) is 37 g
    of protein per day for the standard man with mass
    of body 65 kg for professions of average hardness
    (II group) and 29 g of protein for the standard
    woman with body mass 55 kg.

  • Effects of protein deficiency
  • The effects of protein deficiency may summarized
    as below.
  • During pregnancy
  • Still birth,
  • low birth weight,
  • anemia
  • Infancy and early childhood
  • Marasmus,
  • kwashiorkor,
  • mental retardation,
  • stunted growth and development

  • Effects of protein deficiency
  • Adults
  • Loss of weight,
  • underweight,
  • poor musculature,
  • anemia,
  • increased susceptibility to infection,
  • frequent loose stools,
  • general lethargy,
  • incapacity to sustained work,
  • delay in wound healing,
  • cirrhosis of liver,
  • oedema,
  • ascitis, etc.

Fats are composed chemically of carbon, hydrogen
and oxygen, only in different proportion than
they are contained in carbohydrates. There is
less of oxygen in fats than in carbohydrates.
Fats are a form of concentrated food and like
carbohydrates, they are used as body fuels for
the production of heat and energy. As fats are
not soluble in water, the process of digestion
changes the fat into an emulsion form for their
absorption into the body. Liquid fats and those
which melt at body temperature are somewhat
better digested than those which are much harder.
  • Fats serve the following functions
  • Dietary fat is a concentrated source of energy.
    One gram of fat supplies 9 calories of energy.
  • Fats are carriers of fat-soluble vitamins, e.g.,
    vitamins A, D, E and K.
  • Dietary fat supplies "essential fatty acids".
    Linoleic acid, one of the essential fatty
    acids, prevents scaly skin formation.
  • The fat layer below the skin plays an important
    role in maintaining our body temperature.
  • Fats provide support for many organs in the
    body such as heart, kidney, intestine etc.
  • Foods containing fats are tasty.

Animal sources These are ghee, butter, fat
of meat, fish oils, etc.
Vegetable sources These are various vegetable
oils such as groundnut, gingely, mustard,
cottonseed, safflower (kardi) and coconut oil.
Chemically carbohydrates are composed of carbon,
hydrogen and oxygen as the name implies.
Polysaccharides are various starches which are
converted into two molecules saccharides i.e.
cane sugar, beet sugar, milk sugar and malt
sugar. These on further, glucose and digestion
change into single molecule monosaccharides

Foods that are high in carbohydrates Breads,
pastas, beans, potatoes, bran, rice and cereals.
The original source of all starches and sugars is
green plants. When plants have excessive sugar
and they need to store it, as reserve supply of
food, plant body is capable of changing its sugar
into starch. Carbohydrates are abundantly present
in food. All carbohydrates have to be changed
into glucose and fructose before they can be
absorbed into the body. 1 gm of carbohydrates
yields 4.1 calories of heat. The daily
requirement of carbohydrates varies from 50 to
60 of total energy intake. The carbohydrates
are chief sources of energy. In the active
muscles, the glucose is oxidized for the
production of energy and warmth. Glucose which
cannot be used immediately, is converted into
glycogen and stored in the liver and muscles or
converted into fat and stored under the skin.
There are three main sources of carbohydrate
Starches These are present in cereals (rice,
wheat) roots and tubers (potatoes).
  • Sugars
  • Monosaccharides glucose, fructose, galactose.
  • (b) Disaccharides Sucrose, lactose, maltose.
  • (c) Cellulose This is the tough fibrous lining
    found in vegetables, fruits, cereal, etc.
  • It is hard to digest and has no nutritive value.
    However, cellulose acts as "roughage" and
    prevents constipation.

These are complex organic substances contained in
food and are very essential for the normal growth
and nutrition of animals. In fact, they are vital
accessory food factors required for the
maintenance of optimum, health. They are present
in various foods in minute quantities and diet
devoid of vitamins, if taken for some period,
gives rise to certain diseases known as
deficiency diseases and may ultimately even cause
death. They do not supply energy but are simply
protective foods.
Fat -soluble Vitamins
Water-soluble Vitamins
Thiamine (B1) 
A (retinol)
Riboflavin (B2)
Niacin (B3) 
E (tocopherol) 
Pyridoxine (B6)
Pantothenic acid  
D (calciferol)
Cobalamin (B12)
Folic acid
K (menadione)
Ascorbic acid
Nutritional Diseases
  • 1. Protein Calorie Malnutrition (PCM).
  • (i) Kwashiorkor. It results from consumption of
    very low protein in diets of low biological
    values, yet providing just enough energy to
    satisfy the needs of the child. This condition is
    usually seen in children between the age group of
    1-4 years. This symptom is characterized by
    pitting oedema, anemia, retarded growth, loss of
    appetite, diarrhoea, scanty hair growth...
  • (ii) Marasmus. It is a clinical condition of
    protein energy malnutrition, primarily due to
    total deprivation of the requisite calories
    required by the body. It usually occurs in the
    age group of 1/2 to 5 years. This syndrome is
    characterized by failure to gain weight, wasting
    of muscles and of subcutaneous fat. The child
    feels good appetite but is irritable.
  • (iii) Marasmic-Kwashiorkor. Patients suffering
    from Marasmic-Kwashiorkor show clinical symptoms
    of both Marasmus and Kwashiorkor.

  • 2. Protein Deficiency in Adults.
  • Protein deficiency in adults is also quite
    prevalent in poverty areas.
  • Protein deficiency will result in adults
  • reduced weight,
  • reduced subcutaneous fat,
  • anaemia,
  • greater susceptibility to infection,
  • frequent loose motions,
  • general lethargy,
  • delay in healing of wounds
  • oedema.

3. Mineral Deficiencies
  • Deficiency of iodine in water and feed leads to
  • (ii) Lack of flourine ( lt 0.5 ppm) in water leads
    to caries.

(iii) Calcium deficient diets lead to rickets
and osteomalacia. (iv) Iron deficiency diets lead
to anaemia, (v) There are other important
minerals like copper, selenium etc. Usually their
requirements are so little that deficiency
conditions do not occur.
4. Vitamins Deficiencies
(ii) B Complex Deficiency of Thiamine leads
to beri - beri. Niacin deficiency results in
pellagra. Riboflavin deficiency symptoms are
angular stomatitis, cheilosis, scrotal dermatitis
and corneal vascularisation.
  • Lack of vitamin A results in xerophthalmia,
    Bitot's spots, night blindness and keratomalacia.

  • Other B Complex deficiencies also result in
    glossitis, cheilosis and angular stomatitis
  • (iii) Vitamin C deficiency leads to scurvy,
    spongy bleeding gums, haemorrhages in skin and
    other haemorrhages,
  • (iv) Vitamin D deficiency result in rickets and
  • (v) Vitamin K deficiency leads to
    hypoprothrombinaemia, which further leads to

  • 5. Problems of Overnutrition (eating too much)
  • Proteins/fats/carbohydrates
  • Cardiovascular disease (Leading cause of death in
    the western world) a primary cause is thought to
    be ingestion of saturated fat and trans fat
  • Some cancers
  • Diabetes mellitus
  • Insulin resistance
  • Obesity The main features of obesity are
    overweight and fatness. It is mostly caused by
    overeating and intake of abundance of calories
  • Metabolic syndrome
  • Vitamins
  • Vitamin poisoning

(i) Hypervitaminosis A is at times caused by
excess of vitamin A therapy. The manifestation
are headache, nausea, vomiting, irritability and
anorexia. Carotenaemia is also caused due to
excessive consumption of carrots which is
characterised by yellow skin with normal
conjunctiva (ii) The toxic manifestations of
hypervitaminosis D are anorexia, nausea,
vomiting, thirst, polyuria and drowsiness.
Calcium and phosphorus levels in serum and urine
are raised. Calcium may be deposited in many
tissues also (iii) Fluorosis occurs if fluorine
is available gt 1,5 mg in water. It is
characterised by (a) dental fluorosis, i.e.,
mottled enamel of teeth and (b) skeletal
fluorosis i.e., dense bone formation, severe
spondylitis and even calcifications of ligaments
of spine and tendinous inflamation of other
muscles in severe cases.
  • Food allergies
  • Some people have allergies or sensitivities to
    foods which are not problematic to most people.
    This occurs when a person's immune system
    mistakes a certain food protein for a harmful
    foreign agent and attacks it. About 2 of adults
    and 8 of children have a food allergy.
  • Commonly food allergens are gluten, corn,
    shellfish (mollusks), peanuts, and soy. Most
    patients present with diarrhea after ingesting
    certain foodstuffs, skin symptoms (rashes),
    bloating, vomiting and regurgitation. The
    digestive complaints usually develop within half
    an hour of ingesting the allergen.
  • Rarely, the food allergy chelce can lead to
    anaphylactic shock hypotension (low blood
    pressure) and loss of consciousness. This is a
    medical emergency. An allergen associated with
    this type of reaction is peanut, although latex
    products can induce similar reactions.

The hygienic characteristics of some food-stuff
and their sanitary examination
Wheat It is the most important of all cereals
and is extensively used all over the world. It
contains 60-70 starch, 8-12 gluten and 15
water. The seeds have an outer envelope called
pericarp, which is very hard. It is composed
mainly of cellulose and mineral matter and forms
about 13 of the grain. A middle layer called
endosperm or kernel consists chiefly of starch.
It forms 85 of the grain. The germ or embryo
forms about 1.5 of the entire grain. It is rich
in protein and fat. Flour is prepared by
grinding up wheat.
Rice In fact, it forms the staple article of
diet for half the population of the world. In
composition, it is poorest in proteins, fats and
mineral matter, out of all the cereals and has no
cellulose contents or roughage. Its chief
constituent is starch, which is in a very
digestible form. It is digested within 3-4 hours.
Being rich in starch it is eaten with nitrogenous
and fatty substances, like pulses, fish, ghee
etc., to supply the deficiency in proteins and
fats. The bulkiness of rice eaters' diet gives
rise to two important consequences
(i) it tends to prevent the absorption from the
intestines of the proteins and vitamins contained
in other foods eaten with it, as dais or pulses
(ii) it is apt to cause distension of the
stomach and bowels with fermentation of their
contents, thus result in indigestion and bowel
complaints. The outer layer or pericarp
contains vitamin B1 and its complete removal may
give rise to beri-beri in rice eating population.
Rice does not contain vitamins A, C and D.
  • Barley. It is very nutritious and is
    characterized by its richness in mineral salts
    and fat but is poor in gluten, so it is unsuited
    for making bread.
  • Maize. It is as nutritious as wheat, and richer
    in fats than all cereals except oats. It contains
    10 proteins, 65 carbohydrates, 5 fats, 1-2
    salts and 14 water. Maize is poor in certain
    amino acidssuch as tryptophane. It is deficient
    in vitamins, the anti-scorbic and anti-pellagra
    factors being absent and an exclusive use of
    maize may cause pellagra.
  • Oats or Jao. These are highly nutritious. They
    are deficient in vitamins A and D and gluten.
    Oats are used as oatmeal porridge and should be
    eaten with plenty of milk.

  • Pulses
  • These are mostly legumes and are richer in
    nitrogenous substances that other vegetable
    foods. Pulses include peas, beans, and lentils.
    Owing to their richness in proteins, they are
    called "poor man's meat". Compared to meat,
    pulses are deficient in fat. Pulses also contain
    a good deal of carbohydrates If their fresh state
    they contain vitamins A, B, and C, but when dried
    they lose vitamin C.

Soya Bean It is the richest form of vegetable
proteins but with low fat content, a large amount
of mineral matter and almost complete absence of
starch. Iron content of soya beans varies from
7-30 mg. per 100 gms. The protein is of good
quality and easily digestible. It contains large
quantities of vitamin B1 but no vitamin C and D.
A milk from soya bean is prepared to resemble
more or less the composition of cow's milk. It
contains absolutely no cholesterol. The high
fibre content of soya milk helps relieve
constipation, while high mineral protein and
vitamin (especially B complex) levels provide
"ideal" nutrition.
Roots and Tubers. They exist chiefly in the form
of starch which is about 80 proteins and fats
being practically absent. They contain some
mineral matters which are mainly salts of potash.
The common form of tubers are carrots, potatoes,
beet-root, radish, onions, arrow-root, sago and
Potatoes are rich in carbohydrates and contain
starch 22 , protein 2 and a trace of fat (0.16
). They are a good source of vitamins B and C
and contain iron and phosphorus that is why they
are universally used as wholesome and palatable
dietary articles having much nutritive value.
Green Vegetables. They have little nutritive
value, but form an important article of diet on
account of the presence of vitamins and mineral
salts of sodium, calcium and chlorine, which they
contain. In composition they consist of 90
water, 2 nitrogenous substance or proteins, 4
starch and ½ fats.
They contain large amount of alkaline salts which
act as "buffers" and maintain the alkalinity of
the blood. They supply vitamins A, B1, B2 and C
and give relish to the food, so their inclusion
is essential in an ideal dietary. Green
vegetables are rich in cellulose, so add bulk and
are of value in curing chronic constipation. So
far as possible, they should be eaten raw as
  • Fruits
  • Fruits contain a large amount of sugar,
    vegetable acids and salts. These are protective
    foods. According to their nutritive value fruits
    have been divided into food fruits and flavouring
  • Food fruits are those which afford nutriment,
    and include bananas, dates, figs, grapes, mangoes
    etc. Their nutritive value depends on the
    presence of carbohydrates, which exist in the
    form of sugar and commonly known as levulose or
    fruit sugar. Certain fruits such as lemons and
    oranges are rich in potassium salts, lime and
    magnesia and contain vitamin C.
  • The fruits are valuable because
  • They have cooling effect and quench thirst.
  • They contain important mineral salts of potash
    combined with vegetable salts.
  • They have anti-scorbutic properties being the
    richest sources of vitamin C and for this reason
    they are included in children's dietary. They
    prevent scurvy.
  • They prevent constipation.

  • Nuts.
  • They differ from fruits as they have higher
    calorific and nutritive value, being rich in
    proteins and fats. The common nuts are almonds,
    cocoa nuts, ground nuts, walnuts etc. They are
    rich in vitamin B but contain very little vitamin
    A and no vitamin C.

  • Meat
  • It consists of muscle-fibres held together by
    connective tissues. The fibres of meat contain
    muscle plasma or muscle-juice. It contains 1 to 2
    salts which are chiefly chlorides and
    phosphates of potash. The proteins of meat which
    are present to the tune of about 17 to 20 are
    myosin, muscle-albumen and haemoglobin. Fat (10
    to 20 ) is often embedded in the connective
    tissues of meat.
  • Inspection of Meat. Anti-mortem inspection of
    animals should be done, wherever possible and the
    animals should be rejected, if they appear to be
    ill. The carcase should be inspected after
    slaughtering whole and also part by part and
    subsequently organ by organ. Mediastinal and
    bronchial lymphatic glands should be examined for
    evidence of tuberculosis. If the animal has
    suffered from jaundice, the flesh will have a
    yellow tinge.
  • Characteristics of Good Meat. The muscle fibres
    are of deep red colour and marbelled with fat.
    The reaction should be acidic. It should be firm,
    elastic to touch. It should have little or no
    odour as diseased meat emits odour of
    putrefaction or sickly smell. The fat should be
    firm and of whitish or yellowish grey colour.
    Lymphatic glands should be free from all
    diseases. Any diseased condition, i.e., cysts of
    tapeworms etc., should not be present.

  • Unsound Meat.
  • It is that meat which has begun to putrefy.
  • It becomes soft, moist, pale and often has
    greenish colour.
  • The reaction becomes alkaline
  • ?dour of putrefaction may commence in the deeper
    part of the meat especially near the bones and so
    the odour may not be apparent from the outer
    surface. Therefore, in case of suspected meat, it
    is advisable to push an iron skewer deep into the
    meat pull it out and smell it.
  • The smell should be sweet and agreeable.
  • The juice should be reddish and acidic, since
    alkalinity is an indication of decomposition.
  • Putrified meat is extremely dangerous, as
    poisonous substances get developed, which
    introduce sudden and fatal illnesses due to
    ptomaine poisoning.

  • Diseased Meat
  • The flesh of animals killed by accident,
    lightning or those who happen to be suffering
    from diseases like anthrax, rabies, glanders,
    general tuberculosis etc., should be condemned.
    The diseased meat should be condemned and
    prevented from sending into the market.
  • The chief diseases of animals are
  • Tuberculosis.
  • Cysticercus.
  • Trichinella Spiralis.
  • Actinomycosis or Ray Fungus.
  • Distomum Hepaticum of Liver Flukes.

Fish It is easily digested and is assimiable. It
has a high nutritive value, though not so
stimulating as meat, but generally it is less
rich in fats and contains more calcium than
ordinary meat. It has all the vitamins except
vitamin C. Fish liver is a rich source of
vitamins A and D. Sea fish is a rich source of
iodine. There are two kinds of fish Lean fish.
It consists of small fibres and contains fat
below 2 . It is easily digested. Fat fish. It
consists of medium or large fibres with fat
content of 2.5 or more. It is somewhat difficult
to digest.
Characteristics of Good Fish A fish should have
bright pink gills, firm glistening scales and
prominent lustrous eyes. It should have a bright
and glistening skin with a covering of clear
slippery mucous. It should be free from any
disagreeable odour. When held flat on hand by
head, the tail should not droop. It should not
feel soft or leave an impression or depressed
mark when pressed by a finger. Its skin should be
intact and scales should not be easily
detachable. If not eviscerated a sound dead fish
sinks in water.
A decaying fish has dull grey sunken eyes, grey
muddy gills, the scales become detached and have
a characteristic putrefying smell. It may cause
ptomaine poisoning. It floats in water with belly
up, A putrefying fish shows dark blood or dark
tarry liquid on cutting and its body becomes
flaccid. A large tapeworm called
Dibothriocephaluslatus is conveyed to man by
eating insufficiently cooked fish. Fish poisoning
may occur due to toxins produced by Cl.
botulinus. Its decomposition may give rise to
ptomaine poisoning. It may be found that some
persons possess idiosyncracies especially to
muscles, which are said to cause poisoning by
mytilo toxin. The chief symptoms produced are
dyspepsia, urticaria, swelling of tongue,
numbness of limbs, weak irregular pulse etc.
Tinned Meat and Fish. They are commonly used. It
is very essential to see that meat and fish in
tins are wholesome, not old and putrefied. The
tins should be carefully examined before
consumption in the following ways
On Inspection. There should be no indentations,
holes, soldering defects or signs of gross ill
usage. It should not be rusty. It should have
concave ends and not be bulging or blowing out
indicating putrefaction and formation of hydrogen
gas in acidic medium. A collapsed tin signifies
too much vacuum. All leaking and non-airtight
tins should be discarded. On Palpation. If
putrefaction has set in and gas has formed it
gives a springy feel with a sense of resistance.
It so happens particularly, when air has entered
into the tin through a leaking hole and the
vacuum is lost. On Percussion. If the note is
tympanitic, it indicates unsound tin due to
formation of gas, while a dull note indicates a
sound tin. On Shaking. A sound tin will produce
no sound, but if the contents are putrefied and
are partially liquid then a loose sloppy sound
will be detected.
Eggs A egg's weighs approximately 56.70 gms and
consists of 10 outer covering or shell, 60
white, and 30 yolk. It is a food containing all
the proximate principles of food, except
carbohydrates necessary for the growth and
development of the body. It is a protective food
containing first-class proteins with all the
essential amino acids and have the highest
nutritive value among dietary proteins. In view
of the presence of sulphur in the white of egg,
they are considered as acid forming foods and
resemble meat in this respect.
It consists of an outer shell with its interior
white and yolk. The shell consists of carbonate
of lime, the white is made up wholly of proteins,
the chief being egg albumen and the yolk contains
less proteins and a large amount of fat. Besides,
it contains lecithin, vitalin and the organic
compounds of phosphorus, lime, and iron. It is
rich in calcium salts, anti- neuritic and
anit-rachatic vitamins.
  • Yolk of egg is a valubale food for anaemic
    patients, since it contains iron which is very
    easily digested and assimilated in the body.
    Since the fat present in the yolk of eggs is in
    emulsified form, just like milk, it is easily
    digested and is almost completely absorbed in the
    intestines only 3 of residue is left.
  • Freshness of eggs can be tested
  • by holding them in the hand in front of a candle
    in the dark. Fresh ones being more transparent in
    the centre and stale ones are transparent at
    their extremities. This process of testing the
    eggs is known as Candling.
  • (2) By putting them in 10 salt solution fresh
    eggs will sink, whereas stale ones will float.

Milk It is a food material of special importance.
It is almost complete, an ideal food and
contains most of the proximate principles of a
well balanced diet required for human body. It is
thus the nearest approach to perfect food. It
forms the only diet of children to the age of a
year or so. It is the best source of calcium in
diet both on account of quality and the valuable
assimilable form in which it exists. It provides
proteins of high biological value to the body.
Milk contains the following proximate
principles 1. Proteins 3,5 of total weight,
consisting of 3 Caseinogen, 0,4 Lact albumen,
and 0,1 Lacto-globulin. Milk proteins are of
high biological value. Cow's milk is rich in
casein, and human milk in Lactalbumi 2.
Carbohydrates The carbohydrate in all milks is
lactose or milk sugar (4 to 5). Human milk
contains more lactose than cow's milk
3. Fats 3,5 to 4 in the form of glycerides in
emulsified form. Milk fat is a good source of
vitamins A and D When milk is allowed to stand
for sometime, fat rises to the surface as cream.
Chemically milk fat consists of myristin, olein,
palmitin and stearin. 4. Vitamins It contains
all the vitamins except vitamin E. In summer,
cows, if fed on grass, produce milk containing
large amount of vitamins B, C and D. But in
winter, amount of vitamins A and D in milk is
much reduced. 5. Mineral Salts Phosphates and
chlorides of calcium, potassium and sodium. It is
poor in iron.
  • Average specific gravity of cow's milk is 1.032.
    Lactometer is used to determine the specific
  • Solids other than fat are estimated by
    evaporation to complete dryness, a known weight
    of milk and then weighing total solids and
    subtracting therefrom the fat previously
    determined from percentage of solids, which gives
    percentage of solids other than fat.
  • Milk-borne diseases.
  • The important milk-borne diseases are
  • 1. Directly from the milch animal
  • Tuberculosis,
  • Brucellosis
  • Streptocobbsl infection
  • Malta fever
  • Anthrax
  • 2. Inderectly from the human handler or
  • Typhoid and paratyphoid fevers
  • Cholera,
  • Dysentery,
  • Diphtheria,
  • Viral hepatitis

  • Methods of Preservation of Milk
  • These are as follows
  • (1) Boiling is ancient method of rendering the
    milk safe for human consumption.
  • (2) Pasteurisation. According to WHO,
    pasteurisation may be defined as the heating of
    milk to such temperatures and for such periods of
    time, as are required to destroy any pathogenic
    organisms that may be present, while causing
    minimal changes in the composition, flavour and
    nutritive value of milk.
  • There are various methods of pasteurisation of
    milk. Some of them are as follows
  • Holder or Vat Method. In this method milk is
    heated and kept at 63 to 66C for 30 minutes and
    then quickly cooled to below 5 C.
  • High Temperature and Short Time method milk is
    heated rapidly to a temperature of 72 C and then
    quickly cooled to below 5 C.
  • Ultra High Temperature method The temperature of
    milk is raised to 125 to 150 C for a few seconds
    only and then rapidly cooled

Difference bw pasteurization and boiling
Pasteurization Boiling
Temperature 63 0C-65 0C 72 0C 800C Both iodine and Vit. C decreased by 20 Lactose is not caramelized or chared. Pathogenic organisms are killed and iactia acid forming bacilli. Taste, appearance and food value not charged. Souring delayed. 1.Temperature 100 0C 2. Iodine and Vit. C totally lost. 3. Lactose is completely caramelized. 4. All organisms are destroyed 5. Taste, appearance and food value affected. 6. Souring may be prevented.
3. Sterilisation. This is done by raising the
temperature to 100C and then by maintaining it
for 15 minutes in closed sterilised vessels. It
kills all micro-organisms and their spores. The
disadvantages is that vitamin C and B are
destroyed to one-half and one-third respectively
of their original content. The biological value
of proteins is said to be slightly reduced. It is
unsuitable for feeding infants. 4. Drying or
Desiccation The milk prepared from this powder is
of uniform composition, free from all dangerous
organisms and easily digested by infants, as the
curd formed in their stomach is more flocculent
and finely divided than that of the fresh cow's
milk. The vitamin content of dried milk is
variable. Vitamin C is reduced considerably. So
when it is given to infants, orange juice or any
other vitaminised preparation should be added to
Cream. It is prepared by allowing the milk to
stand for a considerable time in the cold so that
butter fat may rise to the top and then removing
the top layer. The fat or cream may be separated
from milk mechanically through a centrifuge
machine known as a separator or it may be
obtained by churning the curdled milk. Cream may
contain about 50 fat. Besides milk fat, cream
contains proteins and lactose also. Butter It is
the most nutritious and easily digestible form of
all fats. Good butter should neither be rancid
nor have an unpleasant odour. Specific gravity of
butter fat varies from 0.911 to 0.913. Its
melting point is 35.8C. Its average composition
should be Water 12 - 15 Fat
80 - 90 Caseinogen 1 - 3 Lactose
1 Ash 2-3 Salt and
Vitamins -q.s.
Cheese. It is a very concentrated protein food
and methods of making it vary considerably at
different places. It is prepared by coagulating
caseinogen of whole milk or skimmed milk with
rennet. Cheeses differ by high content of
protein (20-25 ), fat (25-30 ) and what is also
important calcium and phosphor.
Depending on quality the food-stuff can be
divided on such groups 1. Products of high
quality - the products which may be used without
restrictions. 2. Non-standard. The products,
which have the certain deviations from
requirements of state standards or
specifications, but it does not interfere to
their realization (for example, chicken eggs of
mass less 40g etc.). 3. Conditionally suitable.
It is products, which can be used after
additional processing. 4. Substitutes (ersatz).
The products with reduced value as natural
substitutes, for example, barley and acorn
coffee. They are allowed to realization, provided
that the consumer would be informed, what kind
product is offered to him. 5. Food Adulteration
It is products, in which premeditatedly
qualitative structure are changed to hide the
certain disadvantages or sings of decay. Such
products are forbidden to realize to the
population. 6. Low-quality. The products concern
to those, which are not suitable to nutrition in
any way, that is, which have the expressed signs
of decay (rotting, etc.).
  • Some of the common practices in different country
  • Rice and wheat There are mixed with stone chips
    and gravel to incrase the bulk.
  • Flour Wheat flour is mixed with soap stone
    powder and cheaper flours such as maize flour
  • Milk Removal of fat and addition of water,
    starch and skimmed milk, milk powder etc. are the
    common types of milk adulteration
  • Butter is adulterated with other animal fats in
    Western countries and in India by other vegetable
  • Miscellaneous Tea leaves are adulterated with
    old tea leaves, leather and saw dust. Coffee is
    adulterated with chicory. Honey is adulterated
    with sugar or jaggery and boiled with empty
    beehives. Papaya seeds are mixed with pepper.
    Powdered condiments and spices often contain an
    assortment of innumerable substances including
    horse dung and brick powder.
  • Some forms of adulteration may not be very
    dangerous e.g., addition of water to milk, cheap
    edible oils to expensive ones, cheap flours to
    expensive ones etc. However, they may
    considerably reduce the nutritive value,
    contaminate the food (e.g. water to milk) and add
    toxins to the food (e.g., kesari dal flour to
    other flour and adulteration of edible oils with
    argemone oil and white mineral-oil, use of
    non-permitted colours in sweets and cordials, and
    that of lead chromate for spices etc.

  • Fortification and Enrichment
  • Addition of one or more dietary essentials to
    some foods in amounts which make the total
    content greater than that found in that
    particular food in its natural state is known as
    Fortification. It also includes addition of one
    or more dietary essentials which original food
    does not contain in its natural state. Enrichment
    means addition of dietary essentials to a food to
    restore the total content of the former. Some of
    the examples of fortification and enrichment are
    as follows
  • Addition of Vit. A and D to milk,
  • addition of potassium iodate to common salt for
    endemic goitre areas,
  • addition of iron and calcium to common salt is
    being considered by the Government of India,
  • addition of synthetic aminoacids foods e.g.,
    lysine to wheat flour etc.
  • Supplementary Foods
  • A number of cheap supplementary foods are being
    formulated, which can provide nutrients at low
    cost, as a supplement to the usual diet.

Food Additives Food additives are non-nutritious
substances which are added intentionally to food,
generally, in small quantities to improve its
appearance, flavour, texture or storages
properties. Food additives are generally used as
food colours, antimicrobials, anti-oxidants and
as stabilising, bleaching and maturing agents.
Their use for a number of techinical processes
such as the maintenance of the nutritive quality
of food, enhancement of keeping quality, making
food attractive to the consumers and providing
essential aids to food processing, is well
recognised. However, their abuse is creating
serious public health problems, because they are
sometimes used to deceive the consumer by
disguising the faulty handling and processing
techniques. Several food additives are under
controversy about their safety and some are
dangerous to health, which are quite often used
in spite of not being permitted by law.
Treatment-prophylactic nutrition is a special
nutrition for workers of harmful enterprises. The
base of this nutrition is rational nutrition,
which is structured according to metabolism of
harmful substances in the human organism and
curative action of some nutrients, which protect
human organism from negative influence of
chemical compounds and physical factors.
Treatment-prophylactic nutrition is an obligate
component of protective health-proving measures,
directed on limitation of negative action of
harmful factors on production on the organism.
  • Treatment-prophylactic treatment is directed on
  • elimination of possibility of harmful substances
    penetration into internal medium of the
    organism from the digestive tract, meaning their
    binding in stomach and intestines
  • quickening of excretion of harmful substances
    from the human organism
  • increasing of general resistance of the organism
    towards harmful factors
  • protection of certain, most damageable systems of
    the organism from harmful action of toxic
  • quickening or on the opposite slowing down toxic
    substances metabolism in the organism (aiming to
    stop their income into internal medium).

In Ukraine there are 3 kinds of
treatment-prophylactic nutrition on harmful
  • Treatment-prophylactic ratios.
  • Milk.
  • Synthetic vitamin drugs.

Introduction of treatment-prophylactic nutrition
as a rule follows after theoretical and
medical-biological investigations directed on
determination of mechanism of action of certain
harmful substances and their combinations on the
organism. Complex interrelations between
components of the mixture are determined during
studying of complex action of several toxic
substances as if they enter the organism
together character of their toxic action may
change (synergism or antagonism). After detoxic
action of different nutritive products and
substances is studied. It is proved that many
nutrients have a considerable detoxicating
action. Thus, pectin substances are able to bind
heavy metals and radionuclide in digestive tract,
preventing their absorption and entering internal
medium of the organism. Sulfur containing amine
acids methyonin, cystin, magnesium salts promote
excretion of some toxic substances from the
organism. Vitamins raise protective capabilities
of the organism.
In case of constant poisonings with chemical
substances their multiple influences on the
organism is often performed, presented by damage
of central and peripheral nervous system,
internal organs (liver, kidneys, respiratory
organs) and blood producing organs (anemia often
develops). General result of the influence of all
chemical substances on the organism is
disordering of functional condition of liver,
which leads to its inflammation (hepatitis), and
after to cirrhosis.
  • Following principles are followed during
    organization of treatment-prophylactic nutrition
  • As a usual result of influence of all chemical
    substances on the organism is disordering of
    liver function, so in treatment-prophylactic
    nutrition a considerable attention should be paid
    to nutrients and substances which increase
    functional condition of liver and limit
    consumption of substances and products which
    overload its work. Products, which increase
    functional condition of liver, are milk,
    sour-milk products, cheese and cottage-cheese.
    Wide usage of milk products in treatment-prophylac
    tic nutrition is explained by considerable
    contents of sulfur containing amine acids
    (methyonin, cystin), which protect liver from fat

2. Quantity of fats should be limited as they
speed up absorption of many chemical substances,
most of which are fat-soluble substances. 3.
Treatment-prophylactic nutrition should be
provided by a necessary quantity of fruit and
vegetables, which are the source of many
water-soluble vitamins, carotene, microelements,
pectin substances and fiber.
4. Treatment-prophylactic nutrition should have
an alkali orientation. Disorder of acid-base
balance of the organism to acidosis side leads to
increasing of harmful substances income into
blood, for example, lead, and moving to alkalosis
side promotes accumulation of many toxic
substances in the organism. Milk, milk products,
fruit and vegetables possess alkaline
properties. 5. Consumption of salt should be
limited, since it promotes water retention in the
organism. 6. Treatment-prophylactic nutrition
should be provided based on general rational
Vegetarianism is the practice of not consuming
the flesh of any animal, with or without also
eschewing other animal derivatives, such as dairy
products or eggs. Some vegetarians choose to also
refrain from wearing clothing which has involved
the death of animals, such as leather, silk and
fur. Veganism, sometimes called "strict
vegetarianism", excludes all animal products from
diet and attire, whether or not their production
has involved the actual death of an animal
(dairy, eggs, honey, wool, silk and down
feathers). Vegetarians have varied motivations
including religious, cultural, financial,
ethical, environmental, and health concerns.
There are many different practices of
vegetarianism. The following table summarizes the
practices of various different types of
vegetarian diet
Foods allowed in the main vegetarian diets Foods allowed in the main vegetarian diets Foods allowed in the main vegetarian diets Foods allowed in the main vegetarian diets
Diet Name Meat (includes fish) Eggs Dairy
Lacto-ovo vegetarianism No Yes Yes
Lacto vegetarianism No No Yes
Ovo vegetarianism No Yes No
Veganism No No No
  • Other dietary practices commonly associated with
  • Fruitarianism is a diet of only fruit, nuts,
    seeds, and other plant matter that can be
    gathered without harming the plant.
  • Macrobiotic diet is a diet of mostly whole grains
    and beans, though it allows the consumption of
  • Natural hygiene in its classic form recommends a
    diet principally of raw vegan foods.
  • Raw veganism is a diet of fresh fruit, nuts,
    seeds, and vegetables.
  • Freeganism argues that all commodities produced
    under capitalism, not only those from animal
    sources, contribute to exploitation and avoid
    buying anything, including food. Freegans thus
    focus on acquiring foods and other commodities by
    means other than purchasing, including dumpster
    diving, foraging for wild plants, and gardening
    with intent to cause as little violence and
    ecological destruction as possible through their
    consumption. While many freegans are vegans or
    vegetarians, others will eat animal products
    recovered from dumpsters that would otherwise go
    to waste on the belief that doing this does not
    encourage further animal exploitation.

Vegetarian diets appeal to people for various
reasons. For some people, religious and
philosophical teachings prompt adherence to a
vegetarian regimen. Other people seek health
benefits. There is much to be said for
most of us making our food choices in the
direction of vegetarian principles, eating less
meat and eggs and substituting foods of vegetable
origin. Such choices will reduce the amount of
fats, particularly the saturated ones, and
increase the amount of fiber consumed. Although
such choices will reduce the amount of protein we
eat, most of us consume more protein than we
need. At the same time, a poorly planned
vegetarian diet can put you at risk for disorders
such as vitamin B12 deficiency iron-deficiency
anemia, growth retardation (in persons who have
not yet achieved their full adult growth), and
osteoporosis. Careful planning is the key to
such a diet. Because many of the nutrients a
human body needs are found most readily in animal
products, finding substitutes requires effort.
  • There are various degrees of food restrictions
    in vegetarian diets.
  • Total vegetarians, known as vegans, restrict
    their foods to those of plant origin only.
  • Fruitarians further restrict their foods to only
    raw or dried fruits and nuts, honey, and olive
  • Lacto-vegetarians eat foods of plant origin plus
    milk and other dairy products.
  • Lacto-ovovegetarians eat plant foods, milk and
    other dairy products, and eggs.
  • Obviously, the question of the
    nutritional adequacy of a particular vegetarian
    regimen depends on the extent of food
    restrictions. Also, children and teenagers,
    pregnant and lactating women, and people
    recovering from a serious illness or injury who
    are vegetarians need to take precautions to
    ensure that all of their body's needs are met.
    Such people should follow a vegetarian regimen
    only with the careful supervision of an
    experienced, registered dietitian.
  • Protein is of some concern when planning a
    strict vegetarian diet. Protein found in foods of
    plant origin tends to have only small amounts of
    one or more essential amino acids. Protein from
    animal sources contains essential amino acids in
    an optimal proportion.

  • Grains and cereals with ingredients including
    wheat, com, oats, and rice provide some essential
    amino acids, while legumes such as peas, peanuts,
    and dry beans provide others. When, during the
    course of a day, you combine a grain with a
    legume, or cornmeal with beans, you have a more
    nearly complete set of essential amino acids.
  • Another important nutrient in the vegetarian diet
    is vitamin B12. Vegetarians who consume milk or
    eggs will get enough of this vitamin. Those who
    do not can eat foods artificially enriched with
    vitamin B12. Some commercial foods made from
    soybeans and other plant proteins are fortified
    with vitamin B12.
  • Vegetarians who eat eggs and dairy products also
    usually receive enough calcium and riboflavin,
    but the vegan has to devise special dietary
    strategies. Many foods of plant origin contain
    calcium, but they may not be as easily used by
    the body because of the presence of fiber and
    oxalic acid in the foods. Oxalic acid and fiber
    may interfere with the body's ability to use the
    calcium present in the foods. Thus, if you are a
    strict vegetarian, you may need calcium

  • Vitamin D, iron, and zinc are other
    nutritional elements needing special attention in
    the vegetarian diet. Most of us obtain vitamin D
    through fortified milk and exposure of our skin
    to sunlight. If you do not drink milk, you must
    rely on sunlight or on a vitamin supplement.
    However, children and pregnant and lactating
    women who are vegetarians should not rely solely
    on sunlight but should take a supplement.
  • The high fiber content of most vegetarian diets
    tends to impair the absorption of iron and zinc.
    Good sources of iron include enriched cereals
    and grains, legumes, dates, prunes, raisins, and
    leafy green vegetables. You can enhance
    absorption of the iron in vegetables by including
    citrus fruit or juice or other foods high in
    vitamin C with meals hat contain plant sources
    of iron. Vitamin C helps increase the iron
    absorption from plant roods. Good sources of zinc
    include legumes and nuts.