Healthy immune system is crucial for optimal health and well being of people at all stages of life. We need to take extra care when it comes to children, as they are vulnerable to infections and parasitic infestation. The body's immune system acts as a powerful defense mechanism, and when it is weakened, it can pave the way for infections and illnesses.

The human immune system is a complicated mechanism comprising of many organs and cells, which all work in harmony to protect us from bacterial, viral and fungal infections, parasitic infestation, and toxins. The healthier the lifestyle and food habits, the better is the immune system. Whereas unhealthy eating habits and lifestyle play havoc on the immune system. To build a stronger immune system, a healthy diet and a physically active lifestyle with adequate sleep, rest and relaxation are crucial.

The power of foods as preventive medicine

We often ignore the fact that the foods we eat every day can bolster or weaken the immune system. Children are prone to choose junk and processed foods in this modern lifestyle and this could have a negative impact on their health. Refined sugars, artificial sweeteners, artificial colours, flavouring agents, additives and chemicals added to these foods tend to deplete the vital nutrients by interfering in the absorption. Besides these, unhealthy fats (saturated fats & trans fats) in junk and oily foods, could weaken the immune system. It is essential to eliminate these immune weakening foods and replace these with healthier and natural alternatives.

• Natural foods such as fruits, vegetables, greens, sprouts, nuts and seeds etc are power-packed with immunity-boosting nutrients such as antioxidants, phytonutrients, vitamins and minerals. Here are some of the important nutrients needed to build immunity and their sources.
• Betacarotene (Provitamin A) found in spinach, pumpkin, sweet potato, carrot and mango help increase the infection-fighting cells.
• Riboflavin (Vitamin B2) present in spinach, beet greens and most other greens, almonds and sesame seeds help strengthen the immunity.
• Pantothenic acid (Vitamin B5 ) is an immune system stimulant and helps in warding off infections. Lentils, Peanuts, sunflower seeds, broccoli and cauliflower are good sources of this vitamin.
• Pyridoxine (Vitamin B6) is needed for the production of antibodies which help against bacterial diseases. This vitamin can be obtained from chickpeas, lentils, bananas, papaya, watermelon, cantaloupe and prunes.
• Folate (Vitamin B9) helps in the building of antibodies which prevent infections. Greens such as mint, amaranth, spinach, pulses and legumes are good sources of this vitamin.
• Vitamin C (ascorbic acid) found in citrus fruits, mango, guava, berries and melons, as well as in green leafy vegetables and sweet potatoes is an important nutrient needed for the immune function. This vitamin enhances the immune cell function and safeguards against infections.
• Vitamin D- the sunshine vitamin helps reduce the risk of colds and flu. Regular sunlight exposure helps to get this vitamin naturally.
• Vitamin E - a potential antioxidant, reduces the stress on the immune system during infections. Almonds, peanuts, sunflower seeds are rich in this vitamin.
• Besides the vitamins, minerals like Zinc and copper are also needed for strong immunity. Spinach, lentils, sesame seeds, pumpkin seeds, cashew nuts provide zinc and help protect the immune system. Copper protects the immune system and is present in legumes, walnuts, beet greens, mustard greens and fenugreek leaves.
• Phytonutrients: these are nutrients found only in plant foods such as fruits, berries, vegetables and greens and are responsible for the different colours of the natural plant foods. Carotenoids, Flavonoids, Polyphenols and terpenes are some of the important phytonutrients which strengthen the immune system and reduce inflammation.
• Healthy fats: Omega 3 fatty acids present in chia seeds, flax seeds and walnuts help reduce inflammatory reaction and support the immune system.

Prebiotics & Probiotics

Gut health and immune health are determined to a greater extent by the presence of healthy intestinal bacteria. These bacteria can thrive well if fibre-rich natural foods are consumed in abundance. The fibres and natural sugars present in certain plant foods act as prebiotics - the media for the healthy bacteria to thrive.

All these immune-boosting natural foods can be incorporated into kids' diet regularly. These foods are mostly colourful and palatable. Children have the natural instinct to choose colourful natural foods such as fruits and vegetables. Just by creating healthier versions of their favourite foods, it would be practically possible to introduce different varieties of fruits, vegetables, greens and lentils into their daily diet easily. As varied nutrients are present in different kinds of foods, the easiest way to get maximum nutrients is to choose plant-based foods which are whole, organic, locally grown and seasonal. This would ensure more nutrient density and variety in a natural way.

Exercise, Rest, Sleep

There is no doubt that exercise enhances overall health and well being. This also applies for the immune system, as exercise improves the blood circulation, which in turn allow the cells and substances of the immune system to move through the body easily. Exercise also reduces stress, which can have a positive impact on the immune system. Chronic stress can have a negative impact on the immune system, whereas a healthy diet and exercise can help build immunity.

When it comes to children, the best form of exercise could be allowing them to enjoy outdoor games and to reconnect with nature. Such physical activities also help children to get fresh air and sunlight exposure, which in turn can boost theVitamin D level. Gardening can be a good exercise as well as a motivation to grow their own greens and vegetables.

Rest and Sleep are essential to bolster the immune system. Children usually need more sleep hours than adults and sleep deprivation could suppress their immune system. Sound sleep can boost the T cell response and thereby improve immunity. Children usually prefer to go to bed early and wake up with the sunrise. Encourage them to respect their innate tendency to be in tune with the circadian rhythm.

In a nutshell, including more plant foods in the whole form, physical activity, rest and good quality sleep and sunlight exposure influence the immune system in a positive way.

(About the author: Dr Saravanan is a BHMS, PGDHSC, CLM by education. He works as a Nutrition and Lifestyle Medicine Consultant.)