The Immune System Demystified: A Beginner's Guide

The Immune System Demystified: A Beginner's Guide

What is Immunity?

 We encounter millions of bacteria, viruses, and other foreign pathogens daily, which can cause ill health or disease. Immunity, in simple terms, is our body's ability to fight these pathogens daily so that it does not disturb our health. The immune system is the in-built defense mechanism of our body that protects us from disease-causing microbes and prevents us from contracting infections and diseases.

Is immunity created, or is it already present in our bodies?

It is both. We all are born with immunity and also develop immunity as we age.

What are the different types of immunity?

Innate immunity: Innate immunity is the immunity we are born with. It usually serves as the first line of defense and is quick. Innate immunity is not specific to any pathogen. It just recognizes danger from any foreign microbe and starts acting. Because innate immunity is different for everyone, some people are more vulnerable to infections than others.

Adaptive immunity: Adaptive immunity is like a continuous process, and we develop it throughout our lives. It is created by our immune system as and when we get exposed to pathogens. Adaptive immunity develops slowly but lasts a long time as our immune system stores it in the form of memory. Adaptive immunity also develops when we get vaccinated.

Passive immunity: Passive immunity is a borrowed immunity that does not last long. It is directly getting antibodies for particular diseases. For example, the antibodies acquired by the baby from the mother via placenta or breast milk. This immunity is short-term and not created by our immune system.

 What does our immune system comprise, and how does it work?

Our immune system is made of organs and cells, primarily white blood cells, which work together to fight invading pathogens and developing infections. White blood cells consist of phagocytes and lymphocytes. Phagocytes eat up the invading pathogens, while lymphocytes consist of B cells and T cells. These cells help the body remember the invading pathogens and destroy them with the existing antibodies or kill them by producing antibodies through an adaptive response.

The entire immune system works towards recognizing the invading pathogens and getting rid of them. The primary organs involved in the immune system are the skin, mucus, gut, and lymph. The Lymph system comprises the spleen, thymus, bone marrow, and lymph nodes.

How to strengthen your immune system?

Maintain a balanced and healthy diet

Consuming a healthy, well-balanced diet that provides all the vitamins and minerals in the required dosage is a great way to boost your immune system. Optimal nutritional status ensures the smooth functioning of all the organs to their full potential, and you can achieve it by including fruits, vegetables, whole grains, pulses, dairy products, and nuts in your daily platter, along with controlled portion sizes.


Be it running, jogging, yoga, or an intense workout, exercising improves blood circulation, helps transport nutrients all over the body, and reduces stress hormone levels. It promotes sound sleep and improves your immune functions.



Stay hydrated

Drinking adequate water aids in better digestion and helps prevent constipation. It helps maintain blood volume and also keeps the gut healthy. Fluid intake could also be maintained by consuming water, fresh fruit or vegetable juices, soups, and stocks.

Get good sleep

A restful sleep of 6 to 8 hours is a must for our bodies. Our immune system and the wear and tear mechanism of the body function the best while we sleep. Good sleep aids in better recovery and helps reduce stress hormones.


Stress negatively impacts not only the immune system but also the entire body. Thus it is crucial to de-stress. Indulging in some activity, hobby, listening to music, or other recreational activities can help unwind and push back the dreaded stress hormones.

Specific Nutrients that help boost immunity and their Food sources

Vitamin C - It is a potent antioxidant that neutralizes free radicals.

Food sources - Indian gooseberries, lemon, spinach, papaya, tomato, bell pepper, sprouts, berries, all citrus fruits, and guava.

Vitamin E - It is a powerful antioxidant and also fights inflammation. It is helpful to maintain heart health and is vital in the formation of red blood cells.

Food sources - Nuts like almonds, hazelnuts, peanuts, sunflower seeds, sunflower oil, safflower oil, and soyabean oil.

Vitamin D - The deficiency of Vitamin D makes a person more susceptible to infections. Vitamin D helps modulate innate and adaptive immunity.

Food sources - Egg yolk, whole milk, and fish like tuna and salmon.

Vitamin A - It is essential for the proper growth and regeneration of cells in the body. Thus it plays a pivotal role in maintaining the health of immune cells like T cells and B cells. It also helps reduce inflammation.

Food sources - Carrots, mango, pumpkin, spinach, eggs, fish, liver, and milk.

Iron - It plays a huge role in immune cell proliferation and maturation.

Food source - Liver, fish, egg yolk, spinach, tofu, broccoli, legumes, amaranth seeds, garden cress seeds, and pumpkin seeds.

Zinc - Zinc helps maintain the integrity of the immune cells like neutrophils and fighter cells in the body. The deficiency of zinc makes the person prone to infections.

Food source – Whole grains, nuts, seeds, sprouts, eggs, shellfish, and liver.

Folic acid - It plays a primal role in producing and maintaining our body cells. The deficiency of folic acid can reduce T-cell proliferation, which is essential for immunity.

Food source - Lentils, leafy vegetables, broccoli, sprouts, dried peas, beans, beet, and eggs.

Omega 3 fatty acids – Inflammation in the body is the precursor to most of our health problems. And omega 3 fatty acids help reduce inflammation, and improve brain, heart, and skin health, thus boosting immunity.

Food sources – Flax seeds, pumpkin seeds, pomegranate seeds, sunflower seeds, and more.

Probiotics – The importance of probiotics (good bacteria) for maintaining gut health is no longer a secret. Since a majority of our immune system is present in our gut, one can easily conclude that probiotics are beneficial for our immunity.

Food sources - Fermented foods, yogurt, sauerkraut, kimchi, tempeh, miso.

Is taking supplements vital to boost immunity?

A wholesome, well-balanced diet is sure to boost your immunity, but are we all able to achieve it? Many factors affect our diet, like food choice, portion size, and busy lifestyle, and the list is endless. When your diet alone is not sufficient to fulfill your daily nutritional requirements, supplements come to your rescue. Supplements like Vitamin C, Zinc, Omega 3, Vitamin D, and probiotics help fill the nutritional gap in the body and boost your immune system.


What weakens the Immune system?

  • Excessive alcohol intake
  • Smoking and tobacco
  • Excess sugar in the diet
  • Consumption of fried junk food and aerated drinks
  • Excess intake of caffeine
  • Sedentary lifestyle
  • Stress


Remember, just as how Rome was not built in a day, so was not your immunity. It is small, correct steps taken every day towards improving your health, which build up a strong immune system.

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