NUTRITION AND HEALTH:
Defination-
Nutrition may be defined as the science of food and its relationship to
health.
The word nutrient or food factor is used for specific dietary
constituents such as proteins, vitamins and minerals.
DIETICS – it 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”
The discovery of vitamins rediscovered the science of nutrition.
Between the two world wars, research on protein gained
momentum. By about 1950, all the presently known vitamins and
essential amino acids had been discovered.
The association of nutrition with infection, immunity, fertility,
maternal and child health and family health have engaged scientific
attention. More recently a great deal of interest has been focused on
the role of dietary factors in the pathogenesis of non-communicable
diseases such as CHD, DIABETES and cancer.
CLASSIFICATION OF FOOD-
There are many ways of classifying foods-
1 CLASSIFICATION BY ORIGIN-
a) Foods of animal origin
b) Foods of vegetable origin
2 CLASSIFICATION BY CHEMICAL COMPOSITION-
, a) Proteins
b) Fats
c) Carbohydrates
d) Vitamins
e) Minerals
3 CLASSIFICATION BY PREDOMINANT FUNCTION-
a) Body-building foods like milk, meat, poultry, fish, eggs, pulses,
groundnuts etc.
b) Energy-giving foods like cereals, sugars, roots and fats, oils etc.
c) Protective foods like vegetables, fruits, milk etc.
4 CLASSIFICATION BY NUTRITIVE VALUE-
a) Cereals and millets
b) Pulses
c) Vegetables
d) Nuts and oilseeds
e) Fruits
f) Animal foods
g) Fats and oils
h) Sugar and jaggery
i) Condiments and spices
j) Miscellaneous foods
NUTRIENTS-
Nutrients are organic or inorganic complexes contained in
food.
They are divided into Macronutrients and Micronutrients.
a) Macronutrients – these are proteins, fats and carbohydrates,
they form the main bulk of food.
, b) Micronutrients - these are vitamins and minerals. They are
called micronutrients because they are required in small
amounts.
PROTEINS –
The word protein by derivation means that which is of first
importance. Indeed they are of the greatest importance in
human nutrition.
ESSENTIAL AMINO ACIDS-
Proteins are made up smaller units, called amino acids. Some
20 amino acids are stated to be needed by the human body, of
which 9 are called essential because the body cannot synthesize
them in amounts corresponding to its needs and therefore,
they must be obtained from dietary proteins.
They are –
a) Leucine
b) Isoleucine
c) Lysine
d) Methionine
e) Phenylalamine
f) Threonine
g) Valine
h) Tryptophan
i) Histidine
Some of the essential amino acids have important biological
functions like formation of niacin from tryptophan, the action of
methionine as a donor of methyl groups for the synthesis of choline,
folates and nucleic acids. There is evidence that cystine and tyrosine
are essential for premature babies.
New tissues cannot be formed unless all the essential amino acids
EAA are present in the diet.
, A protein is said to be biologically complete if it contains all the EAA
in amounts corresponding to human needs. When one or more EAA
is lacking the protein is called biologically incomplete protein.
From the nutritional standpoint, animal proteins are rated superior
to vegetable proteins because they are biologically complete. For
example milk and egg proteins have a pattern of amino acids
considered most suitable for humans.
FUNCTIONS OF PROTEIN-
a) Body building
b) Repair and maintenance of body tissues
c) Maintenance of osmotic pressure
d) Synthesis of certain substances like antibodies, plasma
proteins, haemoglobin, enzymes, hormones and coagulation
factors
e) Proteins can also supply energy when the calorie intake is
inadequate but this is not their primary function.
SOURCES-
a) Animal Sources- proteins of animal origin are found in milk,
meat, eggs, cheese, fish and fowl. These proteins contain all the
essential amino acids in adequate amounts. Egg proteins are
considered to be the best among food proteins because of their
high biological value and digestibility. They are used in nutrition
studies as a “reference protein”.
b) Vegetable Sources- vegetable proteins are found in pulses,
cereals, beans, nuts, oil-seed cakes etc. they are poor in EAA.
PROTEIN REQUIREMENTS-
The Indian Council of Medical Research recommended 1gm
protein/kg/day for an Indian Adult.
ASSESSMENT OF PROTEIN NUTRITION STATUS-
Defination-
Nutrition may be defined as the science of food and its relationship to
health.
The word nutrient or food factor is used for specific dietary
constituents such as proteins, vitamins and minerals.
DIETICS – it 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”
The discovery of vitamins rediscovered the science of nutrition.
Between the two world wars, research on protein gained
momentum. By about 1950, all the presently known vitamins and
essential amino acids had been discovered.
The association of nutrition with infection, immunity, fertility,
maternal and child health and family health have engaged scientific
attention. More recently a great deal of interest has been focused on
the role of dietary factors in the pathogenesis of non-communicable
diseases such as CHD, DIABETES and cancer.
CLASSIFICATION OF FOOD-
There are many ways of classifying foods-
1 CLASSIFICATION BY ORIGIN-
a) Foods of animal origin
b) Foods of vegetable origin
2 CLASSIFICATION BY CHEMICAL COMPOSITION-
, a) Proteins
b) Fats
c) Carbohydrates
d) Vitamins
e) Minerals
3 CLASSIFICATION BY PREDOMINANT FUNCTION-
a) Body-building foods like milk, meat, poultry, fish, eggs, pulses,
groundnuts etc.
b) Energy-giving foods like cereals, sugars, roots and fats, oils etc.
c) Protective foods like vegetables, fruits, milk etc.
4 CLASSIFICATION BY NUTRITIVE VALUE-
a) Cereals and millets
b) Pulses
c) Vegetables
d) Nuts and oilseeds
e) Fruits
f) Animal foods
g) Fats and oils
h) Sugar and jaggery
i) Condiments and spices
j) Miscellaneous foods
NUTRIENTS-
Nutrients are organic or inorganic complexes contained in
food.
They are divided into Macronutrients and Micronutrients.
a) Macronutrients – these are proteins, fats and carbohydrates,
they form the main bulk of food.
, b) Micronutrients - these are vitamins and minerals. They are
called micronutrients because they are required in small
amounts.
PROTEINS –
The word protein by derivation means that which is of first
importance. Indeed they are of the greatest importance in
human nutrition.
ESSENTIAL AMINO ACIDS-
Proteins are made up smaller units, called amino acids. Some
20 amino acids are stated to be needed by the human body, of
which 9 are called essential because the body cannot synthesize
them in amounts corresponding to its needs and therefore,
they must be obtained from dietary proteins.
They are –
a) Leucine
b) Isoleucine
c) Lysine
d) Methionine
e) Phenylalamine
f) Threonine
g) Valine
h) Tryptophan
i) Histidine
Some of the essential amino acids have important biological
functions like formation of niacin from tryptophan, the action of
methionine as a donor of methyl groups for the synthesis of choline,
folates and nucleic acids. There is evidence that cystine and tyrosine
are essential for premature babies.
New tissues cannot be formed unless all the essential amino acids
EAA are present in the diet.
, A protein is said to be biologically complete if it contains all the EAA
in amounts corresponding to human needs. When one or more EAA
is lacking the protein is called biologically incomplete protein.
From the nutritional standpoint, animal proteins are rated superior
to vegetable proteins because they are biologically complete. For
example milk and egg proteins have a pattern of amino acids
considered most suitable for humans.
FUNCTIONS OF PROTEIN-
a) Body building
b) Repair and maintenance of body tissues
c) Maintenance of osmotic pressure
d) Synthesis of certain substances like antibodies, plasma
proteins, haemoglobin, enzymes, hormones and coagulation
factors
e) Proteins can also supply energy when the calorie intake is
inadequate but this is not their primary function.
SOURCES-
a) Animal Sources- proteins of animal origin are found in milk,
meat, eggs, cheese, fish and fowl. These proteins contain all the
essential amino acids in adequate amounts. Egg proteins are
considered to be the best among food proteins because of their
high biological value and digestibility. They are used in nutrition
studies as a “reference protein”.
b) Vegetable Sources- vegetable proteins are found in pulses,
cereals, beans, nuts, oil-seed cakes etc. they are poor in EAA.
PROTEIN REQUIREMENTS-
The Indian Council of Medical Research recommended 1gm
protein/kg/day for an Indian Adult.
ASSESSMENT OF PROTEIN NUTRITION STATUS-
