Do you often fall sick?
Have you ever wondered why some people get sick more often?
This is because everyone has a different immunity. Elders and infants have low immunity and hence are more susceptible to diseases. Immunity refers to the body’s ability to prevent the invasion of a foreign substance (such as bacteria and viruses). Immunity differs from person to person.
How Immunity Works?
Human body is designed in such a way that it can fight against foreign substances and various cells help to maintain the body’s natural immunity.
- WBCs (White blood cells)-
- White blood cells are also called Leukocytes.
- They circulate in the body in blood vessels and lymphatic vessels.
- Whenever a bacteria or virus invades the body, WBCs begin to multiply in number to fight against it.
- Our white blood cells are stored in different places in the body, which are referred to as lymphoid organs. These include the following-
- Thymus— a gland between the lungs and just below the neck.
- Spleen— an organ that filters the blood.
- Bone marrow— found in the center of the bones, it produces Red blood cells (RBCs).
- Lymph nodes—small glands positioned throughout the body, linked by lymphatic vessels.
Why they are called white blood cells?
- The name “white blood cell” derives from the physical appearance of a blood sample after centrifugation.
- White cells are found in the buffy coat, a thin, typically white layer of nucleated cells between the sedimented Red blood cells & blood plasma.
Normal WBC Count
WBC count (per mcL of blood)
9,000 to 30,000
Children Under 2
6,200 to 17,000
|Children Over 2 and adults||
5,000 to 10,000
Types of WBCs/ Leucocytes
- Phagocytic activity means engulfing something.
- Phagocytes surround and absorb pathogens and break them down, effectively eating them.
There are many types of phagocytes-
- They are the first line of defense against any foreign body.
- Neutrophils are the most abundant white blood cell, constituting 60-70% of the circulating leukocytes.
- They defend against bacterial or fungal infection.
- Neutrophils are active in engulfing bacteria and are present in large amounts in the pus of wounds.
- Neutrophils are the most common cell type seen in the early stages of acute inflammation.
- These are the largest type, have longer life span & help to break down bacteria.
- They present pieces of pathogens (foreign bodies) to T-cells so that the pathogens may be recognized again and killed.
- Monocytes eventually leave the bloodstream and become tissue macrophages.
- Basophils are chiefly responsible for allergic and antigen response by releasing the chemical histamine causing the dilation of blood vessels.
- They are the rarest of the white blood cells (less than 0.5% of the total count).
- They excrete two chemicals that aid in the body’s defenses: histamine and heparin. Histamine is responsible for widening blood vessels and increasing the flow of blood to injured tissue.
- Heparin is an anticoagulant that inhibits blood clotting and promotes the movement of white blood cells into an area.
- They attack and kill parasites and cancer cells, and help with allergic responses.
- Eosinophils compose about 2-4% of the WBC total.
- It rises in response to allergies, parasitic infections, collagen diseases, and disease of the spleen and central nervous system.
- Eosinophils are also the predominant inflammatory cells in allergic reactions.
- Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity)
- T cells (for cell-mediated, cytotoxic adaptive immunity)
- B cells (for humoral, antibody-driven adaptive immunity).
- Lymphocytes help the body to remember previous invaders (Viruses, bacteria) and recognize them if they come back to attack again.
- Lymphocytes begin their life in Bone marrow. Some stay in the marrow and develop into B lymphocytes (B cells), others head to the thymus and become T lymphocytes (T cells).
What makes a person immune?
- Lymphocytes act as memory cells and develops antibodies against specific antigen.
- Once you have produced antibodies to a certain microbe—it cannot make you sick again, because you have cells that immediately recognize it and produce the antibodies that destroy it.
- The immunity may last for years, sometimes for life.
- Vaccines act as an immunity booster. Creating immunity by injecting healthy people with dead or altered disease-causing microbes has prevented millions of deaths from measles, polio, diphtheria, flu, smallpox, tetanus, yellow fever, and many other diseases.
How can we boost our Immunity?
Choose a healthy lifestyle. Every part of the body functions better when protected from environmental assaults.
Firstly what should be followed in order to maintain a healthy immune system-
- Avoid Smoking & drinking alcohol
- Diet high in fruits and vegetables
- Being physically active
- Maintaining a healthy weight.
- Get adequate sleep
- Maintaining a good hygiene
- Try to minimize stress
How age is related to our Immunity?
- As we age, our immune response capability becomes reduced, which in turn contributes to more infections and more cancer.
- As life expectancy in developed countries has increased, so too has the incidence of age-related conditions.
- Compared to younger people, the elderly are more likely to contract infectious diseases and even more likely to die from them.
- This happens with a decrease in T cells, possibly from the thymus atrophying with age and producing fewer T cells to fight off infection.
Diet which boosts immunity?
- Micronutrient deficiencies— like deficiencies of zinc, selenium, iron, copper, folic acid, and vitamins A, B6, C, and E — alter immune responses.
- All these deficiencies can be fulfilled by eating fresh fruits, vegetables, legumes, dry fruits, etc.
Some of the Immunity Booster Fruits & Vegetables are:-
1. Citrus fruits
- Vitamin C is thought to increase the production of white blood cells, which are key to fighting infections.
- Almost all citrus fruits are high in vitamin C.
- Some of the citrus fruits include:
- Indian gooseberry (Amla)
- Turmeric is a very familiar spice and also available in every kitchen.
- Not only a spice but turmeric had enormous benefits for skin, gut & also to boost our immunity.
- Curcumin, the compound present in turmeric is a very potent agent and aids in healing wounds and infections. This is the reason, it is often suggested to have turmeric milk.
3. Green leafy vegetables
- Green leafy vegetables tend to have high iron content in them which is really essential for our body.
- It contains many essential nutrients and antioxidants, including-
- Vitamin C
- Vitamin E
4.Ginger & Garlic
- Due to high quantity of anti-oxidants & anti-inflammatory properties, it helps to prevent various infections.
- Ginger is an age old remedy to prevent cough & cold.
- Ginger extract mixed with honey is given to children for recurrent cough.
- Zinc is a mineral that can help boost white blood cells, which defend against invaders.
- Sources include nuts, pumpkin seeds, sesame seeds, beans, and lentils.
- Yoga has been used for centuries in keeping the body functioning fit and fine, holistically.
- However, the benefits of yoga are not just limited to stress relief and mental wellness.
- If practised properly, yoga can recharge your body, get rid of the toxins, negative energy and keep your vital organs functioning well.
- Certain yoga positions can help support, balance and boost the immune system.
- It can also help fight oxidative stress which poses a risk to the healthy cells.
Some of the yoga poses
- Surya Namaskar
- Sarvang asana
- Manduk asana
- Vakra asana
- Gomukh asana
- Bhujang asana
Pranayama can improve Immunity by improving blood circulation, reducing fatigue, reducing stress and improving the physical posture.
- Kapal bhati
What precautions should be taken to prevent COVID-19 infection?
- Wearing a mask always while interacting with people outside home to ensure that you are protected from infection.
- Disinfect your surroundings.
- Sanitize your hands often by using regular soap and water while at home and you may carry a sanitizer while traveling outside.
- Reduce the hand-face interactions as much as possible.
- Practice physical distance while interacting with other people for at least 6 feet from yourself.
Research has proved that those with lower immunity are more susceptible to disease than those with a healthy immune system. As we await a cure for COVID our best bet is to nourish our body with healthy food that aids the functioning of the immune system. A healthy diet and a strong immune system is a strong line of defense.