I’ve heard the common tale many times over the internet that lots of exposure to germs builds a “stronger immune system”. I’m highly skeptical of idea for many reasons.
But instead of getting into that, I want to resolve an inkling of an idea that I’ve had. It’s probably silly and has no scientific basis, but I want to make sure. I’ve hypothesized in my own time, as a young teenager (I’m 21 now) that actually exposing yourself to a lot of germs makes your immune system work harder. Even if it does have the benefit of increasing its performance, it comes with the cost of reducing its overall lifespan - that it’s going to wear out earlier in your life. In contrast, someone who tried to stay as sanitary as possible and only modestly used their immune system (as a fail-safe rather than their main line of defense) will have a lot of resources left in the tank even when he or she reaches 70, 80, or 90 years old, because or she won’t have used all of them up in fighting off all those germs because of not washing after using the restroom, before eating, eating off the floor, etc.
When I was a young teenager, this was one of my justifications for being a vigilant germaphobe. I haven’t been nearly as much, that was just a phase back in the day. But I thought I was doing my body a favor by saving its immune system from having to unnecessarily work and waste its lifetime resources.
Is there anything to suggest that you have a limited lifetime supply of “immune system”, so you should avoid using it as much as possible so that you still have resources left in the tank in case you make it to 125? How ludicrous of an idea is this? Anything scientifically to rule this out?
It does decline in strength as we age, along with all the other body organs slowing down or reducing their function as they wear out. I’m not sure it has a finite capacity, as you put it, although it might.
(The “finite capacity” thing was one theory about AIDS before HIV was identified - that people who kept getting STDs turned their immune systems on and off until the switch jammed in the off position. We know now that this is not true.)
Yeah, so the following question is: does using it a lot help in combating age-related decline or make it worse?
Is it like a muscle, where working it out hard over your lifetime will still keep it decently strong even through very old age?
Or is it like a car engine where the more time you spend revving it unnecessarily high, the more wear and tear it accumulates, and the more you shorten its life?
The immune system is rather complicated, and you should look it up. The adaptive immune system generates antibodies to fight new pathogens. These are generated by T cells and B cells. These have a fixed number of possible antibodies that they can generate - but this number is over 400 million, so there is not much chance of running out.
Consider how many new pathogens an infant is exposed to. So the germs you were avoiding so as not to stress your immune system probably already have antibodies which your body remembers.
Now the immune system, like the rest of our bodies, might become less efficient with age, so all the more reason to build up antibodies when it is still working well.
My wife’s book on vaccines has a good section on the immune system, PM me for details. It comes from a real publisher and is in about 300 libraries, at least, around the world now.
To repeat, when your body sees a pathogen in builds an antibody and remembers it, so seeing it again later is simpler for it to handle than seeing it for the first time.
That’s basically the way vaccines work.
Actually, 400 million sounds pretty low. Isn’t there about one trillion species of microbes on Earth? Or is that 400 million per T/B cell? And shouldn’t T/B cell replication be more so the name of the game than antibody generation? Do T/B cells replicate?
Okay, so I’m trying to lift throughout my life to build a lot of muscles mass and strength so I’m still left with a decent amount as my body declines, and even then can mitigate most of the decline if I keep lifting until I die. That has an obvious solution.
What am I supposed to do to optimize the health of my immune system over the course of my life so as to mitigate the effects of age-related decline as it pertains to it? You say accumulate as many antibodies. How do I do that? And again, what about T/B cell count?
Ok, I’ll put it back, but I think Voyager was much more detailed and informative.
Here is what I originally posted:
It helps. The more germs and viruses you are exposed to while young the more immunity you build up, so by the time you get to a ripe old age when the immune system starts deteriorating naturally, your body will have already built up an arsenal of immunity to most germs and viruses.
If you live a healthy lifestyle, eating healthy food, regular exercise, regular sleep, and avoiding bad habits like tobacco or excessive drinking, it should keep your whole body healthy, including your immune system, through a ripe old age. Although you may need to take vitamin D supplements when you get older as the skin is less adept at producing Vitamin D which is needed for a healthy immune system. Most people get vitamin D naturally when exposed to the sun.
As long as you maintain good health it won’t wear out.
Germ free mice live longer than mice in unregulated environments, if, and only if they are contained in germ free environments. Many factors about their metabolism are measurably different from “normal” mice. They have significant differences in fat production, and utilization, and ability to harvest nutrients in their intestines. The effect on longevity of breeding programs to achieve sustainable population for business reason is not differentiable due to the narrow genetic background of the entire population. (Germ free is a misnomer, but even scientists use it to describe existing strains of gnotobiotic lab animals. They have germs, but those populations are “known” and believed not to include any pathogenic strains.) I was unable to find any reports of a general improvement in the comparative ability to fight disease between these animals and “normal” animals. Introduction to pathogens occurs under controlled conditions, most of which are optimized to achieve reliable transmission for study. Simply exposing the animals to uncontrolled environments produces rapid infections by multiple pathogens in the environment. (The most common use of such animals is to provide test subjects for methods for detection of pathogens.)
Over all, the populations of germ free animals are far more different from uncontrolled populations than simple disease resistance, and they make a poor predictive model for planning personal behavior by humans.
Tris
If only Darwin had call it “procreation by the survivors” instead of “survival of the fittest.”
I try to take heart from the notion that those of us with extremely enthusiastic immune systems (allergies to lots of things) seem to be less susceptible to some cancers. I looked it up once because I was curious.
Not a slam dunk, to be sure, but a happy thought nonetheless.
Even if there are a trillion (or more) species of microbes you won’t see all of them. And the pattern for one might also work for others who are similar.
They were able to create (though mutation, I guess) entirely new pathogens which the immune system then could handle, so it is not like this evolved to handle specific ones in the environment. It is adaptive. It is kind of like if your anti-virus software could recognize a new virus that got downloaded and create a new pattern for it before any harm is done to your computer.
I think standard blood tests do white blood cell counts, so you should be okay there. And a good way of accumulating antibodies is to not be germphobic. Just chill out. It doesn’t mean that if food drops on the floor you say “good” and gobble it up.
You did that enough as a child.
Also, the vast, vast majority of those trillions of microbes just don’t matter to human physiology. It’s only a tiny, tiny fraction that interact with us in any meaningful sense. Of course, a tiny, tiny fraction of trillions can still be a large number, but the existence of such a large number of microbes is not scary in itself.
Since every B-cell (Antibody-producing cell) makes just one antibody (except of constant domain variation due to differential splicing), the number of different antibodies at any point in time is limited by the number of B-cells. However, antibody genes are different from other genes inasmuch as they are “self-manipulating” genes. Our genome does not contain any mature antibody genes, these are generated by random recombination of specific gene fragments when a hematopoetic stem cell differentiates into a B-cell. If this immature B-cell encounters a cognate antigen, it is stimulated and starts proliferating and fine-tuning the antibody sequence by somatic hypermutation. Therefore, although the total number of different antibodies at any time is limited, the population of antibodies is constantly adapting to the types of antigens in the environment. When challenged with a novel antigen (microbe), our immune system can** evolve** a matching antibody response within ca. 3 weeks. A fraction of these evolved B-cells will differentiate into long-lived memory B-cells, allowing a much faster immune response upon a second encounter with the antigen.
In addition to the adaptive immune system, we have an innate, antibody independent part of immune system that recognizes shared features of many pathogens, such as bacterial cell wall components.