NUTRITION - Dr. L. Nagpal


From birth to adolescence, health and development are normally related more to nutrition than to anything else. The food you eat has a strong influence on your health, on chances of developing disease and some types of cancer. The key to a healthy diet is to have a balanced approach. One must have the right kind of nutrition.

One would wonder as to " What is Nutrition ? ". The study of food at work in the body is defined as Nutrition. Chemical constitution derived from the food by the body is known as Nutrients. There are 53 nutrients in the body, which are grouped into various categories. They are carbohydrates, proteins, fats, minerals, vitamins and water. Generally speaking, nutrients are the raw materials for the body to synthesize various substances for survival.

Carbohydrates, proteins and fats are energy yielding nutrients. Proteins, water and minerals are body-building nutrients. Water, vitamins and minerals are protective nutrients. Considering the importance of nutritive food for growing children, mothers should emphasize on proper meals and ensure that their children are eating well. The least parents can do is give a healthy start to their children, so that they develop into healthy adults. It is very necessary for parents to themselves realize and be sure about the basic facts related to different foods and the reason why they should be included in the food plan and how different foods affect growth and health.


PROTEINS
Proteins are the building blocks of our body. Without them, we would not be able to replace or repair our body cells.

What are Proteins ?
Proteins are large compounds of smaller units called Amino acids. Amino acids contain carbon, hydrogen, oxygen, nitrogen and occasionally sulphur. Each species has its own characteristic proteins. The protein of human muscle for instance is different from those of beef muscle.

Importance of Proteins :

a. Proteins are responsible for tissue growth and tissue maintenance.
b. They help in healing wounds and growth of nails and hair.
c. Proteins also produce antibodies, which help to develop the immune system to fight disease.
d. They maintain the water balance in our body. If the protein level falls below the required amount, it will cause water retention in the body.
e. Proteins also maintain the alkalinity of the blood.
f. They are the chief solids present in muscles, organs, glands and body enzymes.

Sources of Protein :
The following table shows the various sources of protein. Each of the foods in the table given below contains 6 gms of protein.

200 ml milk whole   1 medium size egg
6 tablespoon baked beans   20 gms red meat
25 gms chicken   25 gms cheese
50 gms pasta    

Protein Requirements :
The recommended amount of protein in one's daily diet is determined primarily by one's age and sex. The figures set out in the table below are the Estimated Average Requirements (EARs).

Children

Age   Gms per day
0 - 1 year   11.0
1 - 3 years   11.7
4 - 6 years   14.8
7 - 10 years   22.8

The WHO (World Health Organisation) does not give figures for 0 - 3 months so no EAR (Estimated Average Requirements) can be derived. To avoid any confusion, all babies under 1 year have been put together.


CARBOHYDRATES
Carbohydrates are the main source of energy. Carbohydrates occur in two basic forms :
a.    Simple Carbohydrates : i.e. simple sugars such as glucose, sucrose and fructose.
b.    Complex Carbohydrates : i.e. starches, fibre
These complex carbohydrates when eaten are broken down into simple glucose through various chemical processes, before they can be utilised and burnt for the required energy.

1. Simple Carbohydrates :

Sugar :
Sugars are important sources of dietary energy. Glucose is used as fuel for the body cells and our brain is entirely dependent on it for all its functions. Excess sugar is stored in our liver as glycogen. Sugar is found in a variety of foods. Glucose is found in small amounts in fruits and vegetables such as grapes and onions. Fructose is found in fruits, vegetables and honey. Galactose when combined with glucose is found in milk.

Table sugar is a 99% pure source of sucrose. Commercial sugar comes in many forms including caster, icing, white, brown, dark brown, molasses and cubes. The stage and type of processing determines the colour and form of sugar.

How much sugar is needed ?
Research shows that sugar provides 18% of the total energy intake for an average adult.

2. Complex Carbohydrates :
a.    Starches b. Fibre

a. Starches :
Starch is a large complex compound that is made up of many glucose molecules. The more complicated the pattern, the more resistant the starch will be to digest. Raw starch is very difficult to digest. Starch provides up to 80% of total energy intake.
Sources of Starch :
Starches are complex carbohydrates. They are found in many plant foods. The following foods are a good source of starch :

Sources of Starch

Potatoes   Popcorn   Bread   Baked Beans
Rice   Biscuits Pasta   

One may wonder how much starch is needed ? A healthy diet should provide an average of 37% of energy from starches. The same is true for children over 2 years of age.

b. Fibre :
Fibre was originally called roughage. Fibre is the major component of plant cell walls and is resistant to enzymes that digest food.

Fibre can be further classified as :
1. Soluble fibre 2. Insoluble fibre

Soluble fibre : It comprises of foods like oats, barley, rye, peas, lentil, beans, oranges and apples. Soluble fibre has little effect on stool bulk. However, it binds bile acids, which are rich in cholesterol. Soluble fibre prevents re-absorption into your body, so more cholesterol is lost in the faeces and less is taken into the blood stream. This can be important in prevention of heart disease.

Insoluble Fibre : It comprises of foods like whole meal bread, whole meal cereals, biscuits, brown rice, wheat bran and oats. Insoluble fibre increases the bulk and wetness of faeces. It therefore prevents and relieves constipation. It reduces the pressure in the bowel.

How much Fibre is needed :
Research shows that an adult's diet should contain 12 - 24 gms of fibre per day from a variety of sources. There is no specific recommendation for children besides suggesting that fibre intake should be related to body size.

Here is a table indicating some commonly used complex carbohydrates along with an approximate size of each serving. Each serving has approximately 15 - 18 gms of carbohydrates and 80 - 90 calories.

Food   Approx. size of serving
Brown bread   1 slice
Bread sticks   4 small
Chapati plain   1 medium
Idli plain   1 medium
Pita bread plain   (6" diameters)
Cooked Cereals
Dalia   cup
Oats   cup
Suji   cup
Uncooked Cereals
Rolled Oats   2 tablespoon
Break Cereals
Corn flakes   cup
Popcorn   2 cup
Cooked Pasta
Macaroni   cup
Noodles / Spaghetti   cup




FATS
Fat is an essential part of our diet. Fat is essential to perform a number of vital functions in the body in order to maintain good health. One would wonder as to "What are fats ?". The basic building blocks of fat are fatty acids and glycerol. The amount and type of fatty acids one eats, influences the way in which our body handles them.

Importance of Fat

a. Fat prevents extra dryness of the skin.
b. Fat helps to carry fat-soluble vitamins A, D, K and E and in their absorption in the body.
c. Fat is a concentrated source of energy for the body.
d. Fat acts like an insulation layer below the skin, thereby protecting the body from extreme temperatures.
e. Fat protects all the vital organs like the heart and kidney from shock and injury.
f. Fat supplies fatty acids, which are essential for the normal growth of children and for regulating the production of sex hormones.


Types of Fats
One of the major components of fat is fatty acid. There are two categories of these fatty acids i.e :
a.    Saturated fatty acids. b. Unsaturated fatty acids

Based on the amount and the type of fatty acids presents, fats are classified as a. Saturated b. Unsaturated
Saturated fats : Generally fats that originate from animal sources such as butter have a high level of saturation. Saturated fats are more solid at room temperature than unsaturated fats.
Unsaturated fats.: Unsaturated fats are derived from vegetable sources. The less saturated the fat, the more liquid it will be. There are exceptions to this, such as coconut oil, which is a saturated fat but is a liquid.

Have much fat do we need ?
The basic guidelines in a balanced diet are that 30% of the total energy intake should come from fat. Saturated fats should not be responsible for more than 10% of our total energy intake. The recommended dietary intake of Essential Fatty Acids ( EFA's ) for adults is 1 to 2 % of the total energy intake i.e. 2 to 3 grams per day and 1% for children and babies.


VITAMINS
Vitamins are complex chemical substances. They are important for the proper functioning of the various organs in the body. Lack of vitamins can lead to ill health and cause deficiency diseases. A list of various vitamins, their source and the function of each vitamin is given in the chart below :

Name

Source

Functions

Vitamin C
(Ascorbic acid)  
Found in fruits and vegetables, especially citrus fruits, tomatoes, spinach, potatoes and broccoli.   It helps to maintain the skin and connective tissue. It helps in the proper healing of wounds and conversion of iron.
Vitamin B
(Thiamine)  
Found in fortified cereals and bread. Other sources are pork, nuts and legumes (peas and beans).   It helps to break down carbohydrates, fat and alcohol. It is essential for normal growth and it maintains normal appetite and digestion.
Vitamin B2
(Riboflavin)  
Found in dairy products, meat, fish, asparagus, broccoli, poultry and spinach.  It helps to extract energy from fat, proteins and carbohydrates in food.
Vitamin B6
(Pyridoxine)  
Found in poultry, fish, pork and eggs. Also found in oats, peanuts and soyabeans.   It is essential for the metabolism of proteins and haemoglobin (the oxygen carrying red pigment in our blood).
Vitamin B12
(Cyanocobalamin)  
Found in food derived from animals (including dairy products).   Cyanocobalamin is involved in the production of red blood cells.
Folate
(Folic acid)  
Found in liver yeast extract and green leafy vegetables.   It is essential for the normal formation of red blood cells.
Niacin   Found in meat and cereals.    It is involved in fat metabolism and is essential to maintain the condition of our skin.
Vitamin A
(Retinol)  
Found in dark green, orange and yellow vegetables such as spinach and carrots.   It is essential for normal growth. It is also essential for proper night vision.
Vitamin D
(Calciferol)  
Found in fatty fish such as sardines and mackerel, also found in eggs.   It is essential for growth and maintenance of bones.
Vitamin E
(Tocophenol)  
Found in vegetable oils, nuts, vegetables and cereals.   It acts as an antioxidant. It helps in maintaining the structure of lipids in our body and any structures such as membranes surrounding cells that are rich in lipids.
Vitamin K
(Phylloquinone, Menaquinone and Menadione.  
Found in dark green leafy vegetables.   It helps in production of proturomoin, a compound that is required for the normal clotting of blood.