Early years crucial time for immune system

Early years crucial time for immune system

10 September 2012

Children should be taught to practise good hygiene.


The early years are important for a lot of things – development, teaching values, acquiring habits, and even the immune system.

Most of the changes in the immune system happen in the early years, says Dr Chai Pei Fan, consultant paediatrician and paediatric gastroenterologist from Hospital Pantai Kuala Lumpur.

The immune system is a network of cells, tissues and organs that not only protects the body from external elements (bacteria, microbes, viruses, toxins and parasites); it is also smart enough to detect normal human cells so as not to attack them.

Explains Dr Chai: “Besides protection, the immune system is also very important to allow things that benefit the person to get in. In cases where the immune system reacts to cells in the body or certain foods, then you can have an autoimmune disease or an allergy.”

Early years

Although children’s immune systems are still developing after five years, most of the changes happen in the early years.

After the first four to five years, the acquired immune system continues to develop but most of the “learning” happens in the early years.

“In the first 1,500 days or four years, a lot of things happen. Physically, the first four or five years see a tremendous rate of growth. If you look at nutrition for example, the amount of nutrition per kg for children as compared to adults is a lot higher which means kids need a lot of nutrition to grow. 

“Sometimes they may not have enough nutrition to also support the immune system,” says Dr Chai.

Influencing elements

A child’s immune system is influenced by his or her genetic buildup, how the child has been exposed to the environment, nutrition, lifestyle, how active the child is, and the child’s age.

There are two parts of the immune system – one part is what they are born with (genetic) and the other is acquired which develops with over time. 

The acquired immunity is influenced by a lot of factors like environment, diet and lifestyle. Basically, the acquired immunity learns from experience and the experience can come from natural infections. 

“The first time the child is exposed to a particular germ, virus or bacteria, the immune system would react to it – it learns how to deal with it, produces antibodies and also cells that can remember the same germ. So in future, subsequent exposure to the same germ usually will not cause any more infection and the body will know how to protect itself,” explains Dr Chai.

This is why children are given vaccinations to protect against the very severe diseases. By doing this, the child’s immune system is not allowed to experience the infection. Instead, the vaccines teach the immune system to protect the body against these diseases.

What is a weak system?

A weak immune system is one that is not working very well and that means the child’s body cannot protect itself from most infections. Basically, the child would fall sick most of the time and be prone to getting all sorts of infections (not just one type). 

There are children who are born with weakened immune systems or immunodeficiency, which is rare.

Children with immunodeficiency don’t just fall sick with the common illnesses; they fall ill a lot from a lot of infections and different types of infections. These are infections that other people would normally not get.

There is also acquired immunodeficiency – the most common being the HIV infection, which weakens the immune system.

While the cough and cold are very common and children get them all the time, especially if they are in school surrounded by other children, Dr Chai says this is not a sign that the child’s immune system is weak.

Dr Chai: ‘Parents should not worry until and unless their child gets very serious infections.’

“Parents should not worry until and unless their child gets very serious infections or if the child is very ill and requires hospitalisation very frequently,” he says.

To boost a child’s immune system

The best way to ensure your child’s immune system is in top working condition is to practise good hygiene at home, give the child a well-balanced diet and adequate nutrition, without deficiencies in the important vitamins, minerals and proteins.

Usually as children go through minor illnesses they also build up their immune system. It’s part of their growing up process. 

Does this mean that it’s better to expose children to germs rather than being too cautious?

Dr Chai explains the hygiene hypothesis which claims that if a child is brought up in a very clean environment, especially in the early years, his immune system is not able to develop.

“It may not be good in the long run for children. In fact, according to the hypothesis, the imbalance of the immune system leads to more allergies and autoimmune problems later in life,” explains Dr Chai.

Although he is unable to say for sure if this hypothesis is correct, he believes that parents should allow their children to play outdoors rather than limit them to a sterile environment.

“In a way, we encourage parents to have a good and clean environment but at the same time, I think, it should not be to the extent of preventing children from going outdoors to have fun in the playground. Sensible hygiene practices such as cleaning up after coming back from outdoors is good. But not to the extent of making them live in a sterile environment that the body can’t develop its immune system,” says Dr Chai.


Children who are getting breast milk and sufficient nutrients, needn’t take additional supplements. According to Dr Chai, most supplements, like vitamins, are for children above the age of one year old.

He explains that supplements will only make a difference if the child has a deficiency in nutrients.

If the child is well-nourished and the level of nutrients is optimal, taking supplements may not make any difference to the child and the additional nutrients may just be passed out of the child’s body eventually.

Dr Chai reminds parents that probiotics is another supplement and that means that sometimes it may not provide any additional benefit to children if they are already at their optimal health.

He cautions that not all probiotics are the same as the strains are different and have varying effectiveness.

For children, Dr Chai says probiotics can be taken after a long period of taking antibiotics to replace some of the good bacteria which were killed by the antibiotics.

There are many medical studies on how probiotics can influence and prevent certain diseases. Dr Chai says the evidence is very strong for gut infections. There is also research on using probiotics in the long run in healthy children to prevent infections or to reduce allergy. While there are studies to show that it works, Dr Chai says it is still too early to recommend it.

If parents are in doubt about probiotics and other supplements, they should consult a healthcare professional.

Best practices?

– Make sure children get good nutrition and well-balanced meals;

– Allow them to participate in children’s activities and outdoor games; and 

– Exercise is also very important to keep our children healthy.

Taken from ParenThot, thestar online, www.thestar.com.my.