I always have to smile a little when I hear in the advertising what all is supposed to boost the defense power or see happy people who pour themselves vitamin supplements and talk about strengthening the immune system into the camera.
A system like the immune system, which was shaped over millions of years in evolution and is absolutely vital for survival, cannot be “strengthened” by a yogurt or a vitamin supplement – it is usually strong and precise enough, otherwise we wouldn’t stand a chance in the cycle of life with all the bacteria, viruses and parasites around us. So forget about the advertising crap…
The only measure that can meaningfully “support” the immune system is vaccination. Here, the immune system is either presented with a weakened pathogen (example would be the measles vaccine, where a weakened measles virus is injected) or components of a pathogen (e.g. protein sequences of the virus capsid or the virus envelope) in combination with a so-called adjuvant (a substance that non-specifically stimulates the immune system), with the aim of generating an antibody formation. If this is successful, then pathogens can be neutralized directly after entering the human body and are no longer able to infect cells (see also article on adaptive immunity). We would very much like something like this against the new coronavirus – and it is being worked on feverishly.
Therefore, it makes no sense to dwell on the “strengthening of the immune system” in the current situation (so you can safely ignore advertising messages on this topic), but it is more useful to consider what can impair our ability to fend off pathogens.
The main thing is a higher age – like any other “organ”, the immune system also ages and loses its responsiveness. This phenomenon is called immunosenescence. In older people, a number of changes occur both in the innate and adaptive immune defenses that lead to a decrease in the functional capacity of the immune system and thus to an increase in infection-related morbidity and mortality. Now, there is nothing one can do about aging itself – but a healthy life is definitely not a disadvantage, because the state of the innate and adaptive immune defenses in older people correlates directly with the state of health.
A healthy life includes, among other things, dealing well with another important component of innate immunity – namely the epithelial barriers, or more simply put, the skin and mucous membranes. A main interface between the environment and us is the mucous membrane of the respiratory tract, through which the corona virus enters the body. The epithelial surface in the respiratory tract is an important physical barrier between microbes in the external environment and the host tissue. The barrier epithelia also contain certain types of lymphocytes that play a role in host defense by secreting messenger substances, activating phagocytes (phagocytes) and killing infected cells. Loss of integrity of these epithelial layers predisposes a person to infections – this is among other things a big disadvantage that smokers have to accept. Therefore, it is much better for an intact immune system to quit smoking than to reach for a vitamin supplement.
Sport as an essential health factor
Another major health factor is sport. From a study on women over 70 years of age (Nieman DC et al. Med Sci Sports Exerc 1993), we know that regular physical training significantly increases the functionality of natural killer cells compared to those of an inactive control group, and this was associated with fewer upper respiratory tract infections. Accordingly, physical inactivity also seems to increase our susceptibility to infection. For this reason too, I hope that we do not get curfews – because in my view this would be rather counterproductive for health. So let’s all work on ensuring that it doesn’t come to that.
An important circumstance that one cannot influence is when a weakening of the immune system has to be accepted for medical reasons – either because one has a basic disease that directly damages the immune system (e.g. blood cancer) or because one suffers from a disease that necessitates taking drugs that damage the immune system (e.g. chemotherapy for certain tumors).
And then of course there are the many people with an autoimmune disease who take medication to dampen a “too well functioning” immune system. Here too, drugs are used that suppress the immune system, which makes many patients with autoimmune diseases nervous at the moment. The difference from the above diseases, however, is that we try to achieve a good balance between functionality and suppression of hyperfunction/autoimmunity – and in general this is successful and the infection defense remains unaffected.
