Nutrition in infancy: Growth and development

Infancy is a period of rapid growth. The development during infancy is rapid than any other period in the life time of an individual.

 GROWTH AND DEVELOPMENT

The average birth weight of a newborn is 2.5 kg.

The growth and development is accompanied by a number of physiological changes which include

1. Change in body size

A healthy normal infant doubles its birth weight by six months and triples the birth weight by the end of one year. Similarly there is increase in body length of the infant from 50-55 cm at birth to about 75 cm during the first year. With increase in body length the body proportion also changes. By the time the child is two years old the head circumference achieves nearly 2/3rd of its final size and there is an increase in chest circumference.

2. Change in body composition

Weight gain comprises of growth in muscles, organ tissue, skeletal tissue and skeletal structure. At birth the infant has water content as high as 75 percent in its body,12-15 percent fat and poorly developed muscles. By the end of one year the water content decreases to 60 percent and fat content increases to 24 percent and there is a corresponding decrease in lean body mass. Mineralization of skeletal system takes place and continues during childhood and later during adolosence.

3. Changes in gastro intestinal system

A full term infant is able to digest simple proteins, emulsified fat and simple carbohydrates. During the first few months gastric acidity and salivary secretion is low. As the child grows the digestibility improves and by the end of first year the child is able to digest all types of food.

4. Changes in excretory system

Kidneys reach their full functioning capacity by the end of first year. During early months the glomerular filtration rate is low and hence excretion of high concentration of solutes is difficult.

5. Mental development

There is a rapid increase in the number of brain cells in the first 5-6 months after birth. Thereafter the rate of cell division declines though it continues till the second year.

6. Changes in circulatory system

The infants have a rapid heart rate of 120-140 per minute. At birth the level of haemoglobin is 18-22 g/100ml which provides sufficient reserve for expansion of blood volume and adequate oxygen carrying capacity to the growing tissues during the first 4-6 months.

7. Feeding behaviour

Maturation of nervous system especially that which controls muscular co-ordination brings about the change in feeding behaviour.

At birth the baby is able to co ordinate sucking, swallowing and breathing. Although the eyes cannot focus, the baby is able to find its nourishment by rooting reflex. Till about three months the baby sucks by the up and down movement of the tongue which pushes out solid food if placed (extrusion reflex). By 3-4 months the tongue movements change and the child is able to swallow and by 6 months chewing movements also develop.

Growth monitoring

Though the above mentioned growth and developmental changes are significant, satisfactory growth in an infant can be accurately assessed by growth monitoring.

'Growth monitoring is a regular measurement of growth which enables to visualize growth, or lack of it and obtain specific, relevant and practical guidance to ensure continued regular growth and health of children.'

Though growth monitoring can be done in a number of ways the best way to do is by using a 'Growth chart'.

Immunization:

Malnutrition during infancy leads to higher incidence of infant mortality. Besides malnutrition there are certain other factors which compound with it causing mortality. Infectious diseases are one of them and hence it is important to protect the children against these disease through immunization.

Immunization is given at different ages during the first year of life which give life long immunity to the child against six dreadful diseases namely tuberculosis, polio, diphtheria, pertusis, tetanus and measles. So immunization is important not only for nutritionally deprived but for all children. List  presents the immunization schedule.

Immunization Schedule

Age   Vaccine

Soon after birth  Hepatitus B 1st dose, OPV 1st dose, BCH

6 weeks       : Hepatitis B 2nd dose DPT 1st dose OPV 2nd dose

10 weeks: DPT 2nd dose         OPV 2nd dose

14 weeks: DPT 3rd dose OPV 4th dose

6 months: OPV 5th dose Hepatitis B 3rd dose

9 months: Measles

15 to 18 months : MMR

18 months: DPT, OPV 1st Booster

2 years: Typhoid vaccine

5 years:       DPT, OPV 2nd Booster

Source : Primary Health Centre