Our immune system is known to be a very complex organization of various kinds of cells and molecules. Here are some basics about how the immune system works and what you can do to keep it intact.
The orchestra of immune system components
You can imagine the immune system as an orchestra where each participant has their role and all of them playing correctly together results in a healthy and protected body. Those orchestra members are cells and molecules circulating through the body within blood and lymph, communicating with each other and ensuring that we are protected from infections and diseases. Immune system cells are white blood cells called leukocytes (e.g., macrophages, lymphocytes, etc.). Immune system molecules are proteins produced by immune cells or the liver (e.g., antibodies, cytokines, etc.).
Innate immunity – the first line of defense
An organism that can invade our body and cause infection is called a pathogen. Typical examples of a pathogen are viruses, bacteria, and fungi. The most important task for our immune system is recognizing such invaders from non-dangerous agents or our body cells and fighting them. Our immune system can do that in two ways: innate immunity and adaptive immunity. Innate immunity is the general, rapid first line of defense by our immune system, which uses phagocytic cells that can “eat” the pathogen or proteins that can destroy it. The innate immunity fights against all the invaders in the same way and therefore is non-specific and ineffective for all infections.
Adaptive immunity – a trained way of fighting against infection
Our immune system switches to adaptive immunity when innate immunity is not enough. It is slower but utilizes ways of recognizing and destroying a specific pathogen in a specific way. In other words, adaptive immunity needs more time to learn the pathogen and get trained on how to fight it but is more accurate in killing it. The adaptive immunity's primary response to a new pathogen is very slow, while the secondary response is much faster and more efficient. This means the immune system is better at fighting a pathogen that our body has seen before. This is called immunological memory.
Immunological memory serves as a basis for vaccination
Our immune system gets better at fighting against viruses or bacteria after it has already met the invading pathogen used in creating vaccines. A vaccine mimics infection by giving immune system cells and molecules all the needed information about the pathogen without making us sick. If the same pathogen enters our body after a vaccine against it, the adaptive immune system knows how to fight that specific invader and reacts immediately. Therefore, we get a very light version of a disease or do not get sick after vaccination. Due to this, vaccines are the most effective way of preventing infections, which is recognized by public health authorities worldwide.
How to boost your immune system?
The best way of preparing your immune system to do its best when protecting you from getting sick is to stay up-to-date with all recommended vaccines. Some viruses, such as flu, are mutating every year, making it very important to get your flu shot yearly. Besides vaccinations, there are a few other ways that scientific studies have shown to affect maintaining your immune system stronger.
Nutrition and a healthy diet. Many of us have heard that to stay healthy, we need to eat healthily. This is true when it comes to our immunity. Many studies show the importance of nutrition to our immune system. This recent review gives a good overview of COVID-19 and the pandemic. The author explains how important it is to get different substances and nutrients used when the immune system is activated. Such substances are essential for the immune system to be able to work, and we should get them from our diet. The most important in supporting the human immune system are vitamins A, B6, B12, folate, C, D, and E and elements such as zinc, copper, selenium, and iron.
The author mentions other factors impacting our immunity, which are a healthy gut microbiome and maintaining a healthy body weight. Both are closely related to our diet as well.
Sleep is one of the most important factors in keeping your immune system intact. You can read an article about scientific evidence in one of our other articles.
Exercise. For many years, experts have debated the effect of exercise on the immune system, and different studies exist. However, a recent study from 2021 showed that regular, moderate physical activity leads to a 31% risk reduction of infectious disease and a 37% lower risk of infectious disease-related mortality. The researchers did their analysis using data from different studies involving more than 400,000 individuals in total. The study included people over 18 years of age and excluded athletes. Moderate physical activity criterium was considered to be equal to or over 150 min per week performed regularly.
Stress. Research on psychological stress and its effect on the immune system has interested the scientific and medical community for many years. Human and animal studies have shown that psychological stress may also increase the risk of infections and diseases; stress changes the immune response to vaccination and affects tumor growth.
Many studies investigating stress effect on our immunity concentrated on tumor models. One such study from 2018 investigated the effect of chronic stress on cancer prognosis. Using mice models, the researchers showed that chronic stress alters immune system responses toward tumor cells, increasing tumor growth and dissemination.
This scientific review from 2018 presents multiple studies conducted in pigs that demonstrate how stress changes molecules and responses of innate and adaptive immunity. In addition to animal studies, this study from 2016 involved 113 university students and demonstrated the negative effect of stress, depression, and loneliness on the secretion of some specific molecules important in the immune system defense.
It is important to mention that the detailed mechanisms in which psychological stress impairs our immune system are still to be understood.