How to strengthen a child's immunity: what parents need to know

Doctors and pharmacists are constantly searching for new scientific formulas and ways to boost children's immunity, while parents dream of strong long-term disease resistance for their offspring. In this context, it is important to mention that there are still a few simple "vitamins for immunity" that cost nothing – they are accessible to everyone and in every home. Take care of your child's strong immune system now, as this will be the foundation for your adult child's health.

Why is the formation of a child's immune system important for adults?

If a newborn is born with only innate immunity, meaning antibodies received through the mother's placenta and milk, these disappear around 6 months of age, and the baby's immunity begins to learn and train itself. During this period – roughly until three years of age – toddlers very often suffer from common colds and upper respiratory tract diseases. There is no need to fear them – the child's body learns to recognize infections and fight them, with the thymus gland, which produces T lymphocytes, being particularly active at this time.

Around the age of six, a child's immune system is still rapidly building immune memory, as the child interacts a lot with other children – attending kindergarten or other educational institutions, additional classes, and having more contact with other children while playing.

The immunity of primary school children and adolescents up to about 12 years of age becomes increasingly similar to that of adults, so the child is less susceptible to infections. If they do contract various viral or cold-related illnesses, they suffer from them for a shorter duration and with less severity. In adolescence, the thymus gland begins to shrink, immunity is considered more or less mature, and the accumulated immune system memory does most of the work. An adult's immune system has accumulated many memory cells and antibodies, allowing it to react more effectively, specifically, and quickly when needed.

An adult's immune system functions by utilizing the immune system memory created in childhood. This is why adults do not repeatedly contract "childhood" diseases, such as chickenpox. The T lymphocytes, which are crucial for the immune system, mature most actively in the thymus gland during the first 10–12 years. These are like the soldiers of the immune system, fighting against diseases on behalf of the adult throughout their remaining life. This process is widely described in immunology and pediatrics studies, which demonstrate the long-term impact of early childhood on adult resistance to infections.

Thus, how you care for your child's immune system in childhood will determine your adult child's resistance to infections, predisposition to allergies, and resistance to autoimmune and even metabolic diseases, such as obesity.

Weak child immunity – when is it normal, and when should you see a doctor?

Parents often worry whether frequent illnesses in a child indicate a weak immune system or if it's a natural part of immune system development. Especially in the first years of life and upon starting kindergarten, a child's body actively "trains": it encounters new viruses, forms immune memory, and learns to respond more effectively to infections.

Nevertheless, it is important to distinguish situations where frequent illness is a normal developmental stage from when a child's weak immunity may signal potential health problems or unfavorable lifestyle factors.

When is frequent illness usually considered normal?

• The child contracts colds approximately 4-8 times a year, but recovers quickly enough and without complications.

• Between illnesses, the child feels well, is active, has a good appetite, and grows and develops normally.

• More frequent illnesses occur when starting kindergarten or school.

• Illnesses are usually mild and do not leave long-term consequences.

When should you consult a doctor about a child's weak immunity?

• Illnesses recur very frequently and last unusually long.

• Complications often occur (e.g., ear infections, pneumonia, frequent hospitalizations).

• The child recovers slowly from illnesses, constantly feels tired or sluggish.

• There is a lack of weight gain, frequent digestive problems, or other chronic symptoms.

• There is a family history of hereditary immune or autoimmune diseases.

More is not better: common mistakes when trying to strengthen a child's immunity

The popularity of topics on strengthening children's immunity revives in autumn and spring, but it is important to know that immunity formation is a long-term journey. Although there are studies supporting the short-term effect of vitamin intake (for example, vitamin C, taken before a cold infection, shortens the duration of illness), nevertheless, to achieve a long-term result – a strong immune system for the child, and later for the adult – a consistent lifestyle plan is essential. Here, not only supplements are important, but also nutrition, physical activity, sufficient sleep duration, and stress management.

Vitamins for strengthening a child's immunity are a very relevant topic, but it is important to know that it is very easy for a child to overdose on vitamin A and other fat-soluble vitamins (D, E, K). It is safest to consult a doctor and perform special blood tests before starting a long-term course of these vitamins, as an overdose can cause severe poisoning or even liver damage.

It is also important to understand that no vitamins, food supplements, or their combinations can replace vaccinations against specific diseases. Only vaccination (or a past infection) creates the necessary immune system memory, which allows the body to fight the same pathogen faster and more effectively in the future.

For strengthening children's immunity, just like adults', nutrition plays a very important role – the more varied food we eat, the more essential substances the body receives and absorbs. However, it can be difficult to get enough of some immune-critical substances through food – especially for children. For example, fatty fish is not a common choice for children, so, most likely, you will not be able to do without quality fish oil for children, as it helps regulate inflammation, can reduce the risks of allergies and asthma, and shorten the duration of some infectious diseases if contracted. As with achieving any long-term result, fish oil should be given to children regularly.

Three steps to strengthen a child's immunity

Recently, there has been an increasing number of studies on the impact of lifestyle on a child's (and later an adult's) strong or weak immunity. So, what is important for every child?

1. Ensure sufficient sleep

Make sure your child gets the recommended number of hours of sleep for their age, as sleep is critically important for both the formation and functioning of their immunity. During sleep, the activity of immune cells increases, antibody production intensifies, and the body restores protective mechanisms.

Clinical data show that shorter sleep is associated with an increased risk of respiratory tract infections. This means that chronic sleep deprivation can weaken a child's resistance to infections and lead to more frequent illnesses.

Note that specialists recommend that infants up to one year old should sleep 12–15 hours per day, children up to two years old – at least 11–14 hours, children from three to five years old – 10–13 hours, and children and early adolescents up to thirteen – at least 9–11 hours per day. Sufficient and quality sleep is one of the simplest, yet most effective ways to maintain a child's strong immune system.

During sleep, the activity of immune cells increases, antibodies are produced, and the immune system strengthens. For example, children who slept enough after vaccination produced more antibodies against flu, pneumococci, and hepatitis A than those who slept less.

2. Schedule free time in the daily routine

A busy lifestyle, with various opportunities for development, learning, and entertainment, often overloads a child's daily schedule, leaving no time for boredom, rest, or unhurried activities. High expectations (to study well, excel in sports, achieve artistic recognition), and the impact of screens (bullying, constant "availability," being "online," harmful content) create tension and continuous stress.

If a child is constantly tense, stress hormones – adrenaline, cortisol, etc. – accumulate in their body, which inhibits the activity of lymphocytes that fight infections. Moreover, elevated cortisol levels reduce the body's ability to effectively regulate inflammatory processes. Scientific reviews show that chronic stress and associated hormonal changes can significantly weaken immune system function and increase susceptibility to infections. As a result, constantly anxious children may get sick more often, and the course of illness may be prolonged.

Therefore, you can not only ensure a child's quality and long sleep, but also schedule free time – without screens, without obligations, without tasks. Include at least a few hours a day to be calm, even better – outdoors.

3. Worry less about sterile environments and warm clothing

Although the Covid-19 pandemic taught everyone to wash hands more often and use disinfectants, it is still not necessary to sterilize and overly clean the entire environment. Constant disinfection of everything (floors, clothes, dishes, hands, furniture, bedding, handles, etc.) reduces the diversity of microbes needed to train the immune system. By encountering various microbes, a child's immune system learns to distinguish "friend from foe," so it is beneficial for a child to play outdoors, explore, touch, feel, smell, interact with other children, and touch their belongings.

The hygiene hypothesis states that low microbial exposure in early life may interfere with normal immune regulation and increase the risk of allergic or immunological disorders later in life. This idea is based on the analysis of epidemiological data and immunological mechanisms.

A similar situation applies to clothing – there is no need to fear that the child will feel cold, get slightly chilled hands or feet, that a scarf will expose part of the neck, or that they will briefly run outside without a hat in low temperatures. If a child never experiences cold, their immune system does not have the opportunity to learn and train how to react to temperature changes.

Instead of excessively worrying about warm, waterproof, windproof clothing, consider more physical activity outdoors, bathing in water of various temperatures, and gradual hardening.

What truly helps strengthen a child's immunity

The formation of a child's immunity is a long-term process, the foundations of which are laid in early childhood. Although short-term measures can sometimes ease the course of illness, responsible strengthening of a child's immunity relies on daily habits: sufficient sleep, balanced activity, "intelligent" contact with the environment, and a careful approach to supplements.

If a child's immunity is weak, it is important to assess not only the symptoms, but also the child's lifestyle and emotional well-being. Understanding how to strengthen a child's immune system helps parents make calmer, more thoughtful decisions and build a strong foundation for the child's well-being not only today, but also in the future.