Why do we still have allergies if humans have lived around plants for a long time?
In: 31
Allergies are caused by an overactive immune system. The immune system is supposed to protect us from things that can make us sick, like bacteria and viruses. Sometimes, the immune system mistakes harmless things for germs and attacks them. This can cause an allergic reaction.
So many things. So many, many things.
For example: You can be allergic to plants that are not native to where you spent most of your life. There are people who are allergic to pineapple. Bananas.
If it doesn’t remove you from life, and you have kids, they might inherit the same allergies.
Emergency medical care often saves people from anaphylactic shock.
We have allergies to different things. To different plants. That’s why many are seasonal.
It’s a cruel world.
Hygiene hypothesis:
Our immune system has coevolved with many nasty critters all trying to harm our body throughout human existence. It has developed many weapons to counter the invaders since many of the invaders (bacteria, viruses, parasites) were quite deadly.
In the past hundred years, many of those nasty critters no longer affect us. We don’t live out in nature anymore. But the immune system still has memory of the past, along with its arsenal of weapons. Your immune system still fights as if its in a war zone.
There is evidence that this contributes to allergies and autoimmune diseases.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2841828/
The environments that western children grow up in are typically very clean- this cleanliness prevents children from being exposed to pathogens they would otherwise naturally encounter. Encountering pathogens helps build up immunity to them. So, by spending very little time outdoors and having clean/sanitized homes and schools, kids immune systems don’t have a chance to develop defenses for these allergens, and instead become hyper sensitive.
One reason is that apparently in the USA we plant mostly male trees because apparently cleaning up the nuts from female trees was considered inconvenient. All these male trees release their pollen with not enough females to recieve and our environment ends up covered in what is essentially tree sperm.
This unnatural selection has changed the ecosystem of plants and humans amd lead to a significant spike in allergy related issues.
Few good answers already, but part of it is inverse darwinism.
Advances in medication and awareness made it so you are much more likely to reproduce despite having deadly “defects” that would have eliminated them from gene pool in the past.
You can see it with nut alergy, number of cases exploded in last few decades. Part of a reason is that all the food is now labeled, schools have epi-pens. Etc.
So children with those deadly allergies get to live and procreate (and be part of the statistics)
Here is my take on it:
I highly doubt that allergies come from nature alone. Bear with me for a second.
Most of your immune system works with your intestines. Your gut health is a huge, huge factor. In the industrial world, our food is far from natural. Most things that you can buy in a store are polluted with chemicals, toxins, E171 (Titane Oxide) for example has been forbidden in the last couple of month, but was allowed for a much longer time.
I think it is not too far fetched that allergies or immune reactions in general have something to do with what you eat. Like if you smoke to much and the cilia in your lung stop working, your immune system is confused and does no longer know what to do.
I tried many, many things to lessen my allergies, here is what helped me in the end:
– Vitamin D is a huge factor in many immune problems. Make sure that your Vitamin D level is where it needs to be. If you cannot be outdoors too much, use supplements (but research till you find the good ones). Check with your doctor, because there might be a problem with Vitamin D utilization in your body
– Try to eat as much nuts, salad, vegetables and fruit as possible
– Avoid the wrong fats, this might be a huge factor in cancer as well
– avoid processed food like fries
– avoid alcohol and smoking and other obvious toxins for your body
I know it is hard to stay away from the “forbidden” stuff, I have the same problem, but you don’t need to be perfect. You can do better tomorrow than you did today. Don’t give up, experiment yourself, there is a solution for everything. Your body wants to tell you something, learn its language. But not every body is the same and not every body uses the same language. Find your own way.
We haven’t been around ALL plants for ALL of that time.
Many Asian people can’t tolerate milk because they basically don’t have a massive diet of milk. It’s around, they come into contact with it, but they’ve never needed to adapt to it. And every plant is “around”, you don’t come into contact with it, and have no need to adapt to it. So you can form allergies over generations.
Plus, the flora/fauna of one area can be wildly different to that just a few miles away.
Also, most allergies are from *under* or *over* exposure to a substance. Peanut allergies are highly correlated to advice to pregnant women to avoid peanuts. They no longer give that advice, because it literally made babies more likely to become allergic (as they never were exposed to peanuts at a young age or in the womb).
The same works for being swathed in a particular substance all the time, you can still become allergic to something that you’ve been eating or exposed to for years if you are exposed enough.
The body deals with what it needs to. It can’t do everything, it can’t remember everything, and it doesn’t know what things are. New or unusual or rare substances may well trigger an allergic reaction. Many people are allergic to kiwi, because it’s just not the kind of thing that most modern humans are ever exposed to. The body doesn’t know and it takes a best guess and sometimes it gets it “wrong” (but who can blame it, it’s just an organism trying to survive in a hostile environment full of pathogens).
Some people’s immune systems aren’t very clever and get it wrong far more. Some of those people’s systems were damaged by under- or over-exposure in general (e.g. if you lived in a sterile bubble, your immune system wouldn’t develop, so almost anything could be hazardous to the point of fatal when you are then exposed to it, even just a common cold or a simple foodstuff). We gave some people lots of problems by bringing them up in a polluted environment and the body is constantly under attack, so it can overreact to all kinds of things as it’s just trying to survive.
And often such over- or under-reaction is often fatal because the immune system is the only guardian against a knife-edge between you living and dying in a “goldilocks” zone of survival on a rare planet sustaining fragile life in a narrow window of a “goldilocks” zone that supports life, in an otherwise sterile and lifeless universe.
And the immune system, and the body in general, are only trying to survive. If you don’t survive, it really doesn’t matter, long term, in terms of the human race and the billions of organisms that make up your body. If you manage to reproduce before you die, that’s a bonus. If the majority of people manage to live long enough to reproduce and sustain the race, that’s sufficient. That there are a few outliers from the 8-billion-and-growing population of one very specific species, who might not survive against ordinary and mundane things that the others survive, it really doesn’t matter. It doesn’t mean the “design” of the human immune system is flawed, or that you could fix it perfectly forever. Those people are literally in the error margin. The human immune system is still an incredible and highly-successful defence mechanism.
This is not ELI5 level, but I wanted to point out a big detail. Your common allergies come from your body having an immune system reaction against a certain sugar or protein, called antigens. These antigens can be from anything. Bacteria, viruses, fungi, plants, or in the case of autoimmune diseases your own body. Your immune system makes it’s own unique protein antibodies (there are other receptors that are too detailed for this thread) that are like a lock and key match for antigens. Since there are so many antigens in the world and possible threats we need to defend, we evolved a mind blowing trick for making antibodies. While we still have base DNA that is inherited and use as a template for antibodies, we reshuffle and recombine our gene sequences to get millions of combinations. These are random combinations so the results aren’t guaranteed. Our body tries to eliminate any cells that get a combo that attacks our own body or common things that we are exposed to, like food. However if there is a reaction to something we aren’t used to that cell line is stimulated to reproduce, and we get stronger reactions. That is why we can get vaccines to fight diseases. Unfortunately this can also lead to allergies.
It doesn’t impede our ability to survive and procreate. It might even offer some advantages.
Latest Answers