Overview of the Immune System

The immune system consists of highly specialized cells that produce functional responses against any pathogen. The tonsils, spleen, lymph nodes, thymus, and bone marrow are organs comprising the immune system.

The immune system neutralizes infections and diseases by producing antibodies. Antibodies are protein substances that counteract specific antigens that invade the body.

The BMJ Public Health Emergency Collection explores the four functions of the immune system as vigorous defenses of a host. First, it serves as a barrier against any pathogen. Second, it detects what is harmful to the body and reacts to it.

Third, the immune system eliminates pathogens by producing antibodies and promoting the process of phagocytosis. Finally, the immune system generates a memory (immunological memory).

It means the immune system can recognize the same antigen and initiate an immune response that was previously activated.

Why Elders Have Lower Immunity?


Not everybody has similar immune responses. Each body reacts differently. People who have co-morbidities and advanced chronological age have a higher chance of getting infected with respiratory illnesses such as COVID-19.

Generally speaking, older people have a weaker immune system due to a decrease in the production of natural killer cells and other lymphocytes that are associated with aging. However, there are easy steps to strengthen immunity, and people over 65 years old can still get protected from the virus.

1. Be Active in Any Way

The Nature Public Health Emergency Collection examines the association between regular physical activity and improving the immune response.

Researchers report that physical activity boosts immune responses by increasing the activity of macrophages and circulation of immune cells, thereby lessening pathogen overload and the influx of inflammatory cells.

They added that regular moderate to high-level exercise also shows improvement in cellular immunity resulting in increasing infection resolution.

2. Consume the Best Foods for Immune Strength

Poor nutrition is detrimental to patients who are susceptible to COVID-19. Nutrition is an essential requirement for a healthy, functioning body. We get the nutrients that we need to fight off infection from the food that we eat.

Consume the best foods for immune strength, such as fruits and vegetables that are rich in Vitamins A, C, D, E, zinc, selenium, and B-complex.

Popular immune boosters include red bell peppers, turmeric, garlic, broccoli, spinach, ginger, almonds, green tea, and kiwi.


3. Support Immune System with Herbs and Supplements

People who experience limited food availability and inactivity may consider taking supplements to strengthen the immune system. Vitamin B complex, C, D, and zinc are essential micronutrients that play a role in protecting the body against infection and flu-like symptoms.

Consuming certain herbs may also benefit the immune system. Ginseng, garlic, and echinacea are popular powerful antioxidants and immune boosters.

Natural, Simple Ways to Strengthen The Immune System

Below are some healthy tips on how to strengthen immune responses during the pandemic:

1. Get a full night’s sleep

The importance of sleep during a global pandemic cannot be overemphasized. Sleep has a direct influence on immunity. Sleep deprivation and fragmentation increase susceptibility to common colds.

On the other hand, a good nocturnal sleep shows to increase the production of lymphocytes, enhance the formation of immunologic memory, and determine infection risk.

2. Eat mindfully

People who devour nutritious food have a more robust immune system and are less susceptible to infections. Eat a variety but a well-balanced diet with particular attention to proteins.

Proteins have anti-viral and immune properties and contribute to immunoglobulin production. Another tip for healthy eating is to avoid processed and highly salted foods.

Limit salt intake to no more than 5 grams per day. In animal studies, mice that consumed salty foods have developed more severe infections than mice that consumed less amount of salt.

3. Use healthy fats

Good fats are monounsaturated and polyunsaturated fats that are healthy for the heart. Seafood, olive oil, soy, flaxseed, sunflower oil, avocado, and nuts help improve blood cholesterol levels and reduce risks of cardiovascular diseases.

They also help optimize immune function by improving neutrophil chemotaxis and promoting phagocytosis. Always opt for home foods, and limit intake of trans and saturated fats from takeaways, fried foods, and processed meats.


4. Take fermented foods

Fermented foods are any food that underwent fermentation or the process of changing carbohydrates to organic compounds with the use of anaerobic yeast or bacteria. Alcohol, kimchi, and yogurt are examples of fermented commercial products.

Research shows that fermented foods have health-promoting properties. According to the Nutrients[1], fermentation encourages the antioxidant activity of food, alleviates high blood pressure, improves digestion of proteins, and addresses lactose intolerance.

In terms of immunity, fermented foods have a good vitamin content, particularly Vitamin D and B complex – the best vitamins for immunity alongside Vitamin C, zinc, and selenium.

5. Ditch sugar

Bacteria and viruses thrive very well in a ‘sweet’ environment. Too much intake of sugar weakens the immune system, thus increasing susceptibility to infections. Sugar can be an immune system buster when consumption exceeds 75 mg per day.

The recommended daily intake of sugar is 25 mg per day. Cut back sugar by using honey, spices, or extracts instead of sugar, swapping out soda and cans in syrup, and comparing labels or reading the ingredient list.


6. Keep the fluids coming

Drink plenty of water and fluids. Fluids may include tea, coffee, smoothies, milk, juices, and many more. People are advised to drink up to 1.5 L of fluids daily. Drink healthily and avoid drinks with excessive sugar and caffeine content. Too much caffeine and sugar weaken the immune system and reduce its ability to fight off infections.

7. Learn to de-stress

When a person encounters chronic stress, it downgrades several immunity functions of the body, thereby increasing vulnerability to infectious diseases. Also, studies reveal that people who are stressed are likely to resort to alcohol drinking and sleep deprivation as effort measures to manage stress & anxiety during COVID-19.

In addition to that, stress can trigger an adverse change in immunological functions, contributing to so-called ‘sickness behavior’ that may involve depressed mood and reduced social interaction.

Why a Healthy Immune System is All We Need During this Pandemic

COVID-19 is a powerful, one-of-a-kind, novel virus, which has not been encountered, recorded, or widely studied. There is no present cure for COVID-19.

The world is still contesting for solutions that will save humanity from contagion. However, natural health doctors have a different take on facing this serious health crisis.

For them, people only need a healthy immune system to be flu-free – or at least, making people less susceptible to coronavirus. They contend that by eating nutritious food, exercising regularly, having a good sleep, and managing stress and anxiety, people can counter the virus. Indeed, a healthy immune system is a friend during this difficult time.

Of course, a healthy immune system will not deter any person from contracting any disease or infection without maintaining social distance and washing hands regularly.


COVID-19 has affected men and women of all ages, status, and religion. It has made people’s lives harder these days and more impoverished. The virus has taken a toll not only on physical health but also on mental and social wellbeing.

Today is a critical moment to remain fit and healthy in surviving coronavirus while the country leaders strive to find the best solution for it. While waiting for the approved and registered vaccine against COVID-19, a healthy immune system remains the best weapon against the virus.

A robust immune system has a key role in protecting the human body from pathogenic diseases and maintaining a healthy body system. Following the above natural and simple measures will help the world become less vulnerable to respiratory infections, particularly coronavirus.

Proper nutrition, consumption of herbs and supplements, getting enough sleep, hydration, and managing stress and anxiety contribute to maintaining the optimum function of immune cells, hence enduring immune response to COVID-19.