eli5: Why does it seem like everything is carcinogenic and does that mean if it is, it causes cancer?

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I feel like I am always hearing about how things are carcinogenic, like red meat or air conditioners or aspartame. Why does it seem like *so* many things are carcinogenic and does that mean they cause cancer? Because it’s starting to feel like everything causes cancer…

This is the type of thing that gets my anxiety going so I’d love if someone who understands this better than I do can explain it.

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24 Answers

Anonymous 0 Comments

That’s easy. Everything *does* cause cancer.

OK, that isn’t strictly true. However, the number of things that increase your risk of certain cancers is enormous. While minimizing your risk of cancer is a good idea, avoiding anything close to all carcinogens just isn’t going to happen.

Carcinogens *can* cause cancer. This doesn’t mean that they will, just that they can. And while there are things it is worthwhile to avoid, you just kind of have to accept that you will encounter them in your day-to-day life.

Anonymous 0 Comments

Many many many things are carcinogenic. Sunlight is carcinogenic.

You really shouldn’t worry about it too much. Media uses scare tactics like saying “Doing this will double your chance of getting cancer!” That sounds terrifying, but when you look at the numbers and see that it really just takes your odds from 1/10000000 to 1/5000000, it puts that into proper perspective.

Anonymous 0 Comments

Yes, many many things can cause cancer. The oxygen you need to live causes the cancer, smoke causes cancer, the sun causes cancer, all sorts of natural oils cause cancer.

To limit cancer risk, you just limit hazardous exposure. There’s a lot of randomness in the world – no matter what you do your cancer risk is somewhat beyond your control.

Anonymous 0 Comments

There is also a high false positive rate because of a California law. They made a law requiring a warning any time something from a list of carcinogens is in a product. Some companies just apply the warning to everything just to be safe from liability

Anonymous 0 Comments

So George Carlin’s fake news headline “Scientists discover saliva causes stomach cancer” bit wasn’t really that ridiculous

Anonymous 0 Comments

Anything that destroys cells is “carcinogenic”

Thats what cancer is, mistake in replication / repair process that causes the cell to never die. Most cell when encountering mistakes in DNA are either harmless or just dies.

The more your body needs repairs, the higher the probability of fuk up. This is why smoking causes cancer.

Anonymous 0 Comments

As others have said, basically *everything* is carcinogenic in some way. Every second you spend in the sun is a second that your skin is getting flooded with UV radiation, and every second represents a tiny incremental risk that one of those photons is going to be “the one” that hits the right spot in the right DNA of the right cell to cause it to glitch and start dividing uncontrollably.

A lot of people have trouble with gauging risk, and if they hear that you have “5x the risk of melanoma”, that sounds awful but it might just mean an increase from 0.00005%/day to 0.00025%/day. You might have a very different idea of how important that is to you if you only hear the “5x” or you only hear the “0.00025%”.

A lot of the “this is known to be carcinogenic” labeling stuff comes from California law, which requires labeling for things that are “known to the state of California” to be carcinogenic. It’s a long list. The problem with the law is that companies get penalized really hard if something on that list is in their product and they don’t label it, *regardless of whether they knew it was in there or not*. So companies just put the label on basically everything, even if there’s nothing on the list actually in their product, because everybody knows it doesn’t mean anything, and there’s no penalty for over-labeling. So don’t stress about the labels!

For anxiety, here are a few things to consider:

1. Therapy! Professional therapists are specifically trained to deal with exactly this kind of thing and can give you some tools and coping strategies (and if needed, medication!) to help you work through some of this. People do this all the time and it’s easy enough to start with one visit to see what they can do for you without committing yourself.
2. Education! Watch some YouTube videos about chemistry, how cancer works. When you encounter a chemical that someone told you is dangerous, do some research into it. Understand how to read statistics and probabilities and what different concentrations mean, and then try and work out what your *real* risk is.
3. Wear sunscreen!
4. See your doctor once a year, and get screened for the things they think you should get screened for (and don’t push to get screened for the things they don’t).
4. If you find yourself getting exposed to stuff like this through social media, like Instagram or TikTok, keep in mind that the algorithms try hard to feed you the content that it knows that you keep pausing on and engaging with. If you’re doing this about things that you’re anxious about, this is just going to make your anxiety worse. Whenever you feel like you’re having negative thoughts about stuff you’re seeing on social media, take advantage of the platform’s “dislike” or “stop showing me things like this” options so that you can train the algorithms to keep you away from things that don’t make you feel good. This can have a HUGE effect on anxiety and wellbeing.
4. Practice acceptance of your mortality. The simple truth is everyone dies in the end. You have about a [1-in-5 chance it’ll be cancer](https://www.cancer.org/cancer/risk-prevention/understanding-cancer-risk/lifetime-probability-of-developing-or-dying-from-cancer.html). Even if you make yourself impervious to cancer, which you can’t do, then it’ll just be something else. Repeat to yourself in the mirror every morning: my body will eventually fail me. And love it anyway. And use the time you have.

Anonymous 0 Comments

Remember “The dosage makes the poison”. Almost anything is carcinogenic add or poisonous in big enough doses. But how big a dose are you realistically taking?

Anonymous 0 Comments

>I feel like I am always hearing about how things are carcinogenic

That’s down to a couple of things.

1. Media is for profit. It’s easier to get clicks, reads, etc. if you have a clickbait title about something being carcinogenic.

2. Most media’s ability to report on scientific research is extremely lacking. I’ll get to this later on.

3. Scientists aren’t necessarily the best at communicating their findings. That’s not their jobs, so that doesn’t help with point 2.

Regarding media’s poor (I would personally call it terrible a lot of the time) scientific reporting. One is that the journalists are not often scientifically literate. That’s not their primary job and having a journalist that is scientifically literate also means that they’ll have some kind of scientific background to boot. That makes these people rare. Then, a good scientific journalist also has to have the humility required to recognize when they’re outside of their own areas of scientific knowledge. Note that this doesn’t mean that they can’t report on things they don’t know about, just that they know what they don’t know. They should still be able to determine with some amount of accuracy what is good science and what isn’t by looking at who the respected scientists are in their fields, where the study comes from and also importantly be able to tell if the results are preliminary or if there is a very good body of evidence for it.

Now, add to that the fact that news outlets have the annoying tendency of trying to contact researchers for interviews the day of or a day in advance. That means they get turned down a lot. It’s rare that a scientist would be ready for any kind of interview on short notice. It’s something I have seen often enough in academia that colleagues and I used to joke about it.

Add all that together and you get headlines about anything causing cancer the moment there is any kind of possible link between something and cancer. The news also often don’t report when further research shows there wasn’t a link or that as u/ColSurge mentioned, the probabilities are very low.

Finally, I will add that there are scientists who are good at communicating science to the general public and there are also journalistic outlets that are good at communicating science too. As an example, Arstechnica doesn’t cover everything, but what they do cover, they usually do well. It also helps that the readership can be pretty harsh if they make errors. They’re mostly tech with some science related news (weather, space, some health articles). A lot of their writers also hold degrees in related fields and are former scientists.

ETA: Another thing is the dose you’re exposed to. Some things when exposed to in large quantities can be carcinogenic (think ridiculously high doses), others are particularly nasty and you should avoid at all costs, and finally some fall in between. For example, I would be much more worried about smoking than nitrites in charcuterie unless I were to eat the latter every day for every meal.

Anonymous 0 Comments

Studies that find something to be carcinogenic (cancer causing) make the news because it creates an emotional response in people (fear) which sells well. This makes it seem like “everything” causes cancer, you hear about *every* study.

Cancer is caused when cells act odd, aren’t killed off by the immune system, AND they start to grow without limits. Sometimes they also spread (metastasize). This can be caused by your genetic history – something you inherited, random chance, or things that are known to harm our DNA and make them act oddly (carcinogens). [You can read more here.](https://www.cancer.gov/about-cancer/understanding/what-is-cancer#:~:text=Cancer%20is%20a%20disease%20caused,are%20also%20called%20genetic%20changes) The more exposure you have to things that can damage your DNA the more likely you will get cancer.

If the news about this kind of stuff is upsetting, which I understand as someone with a family history of cancer, then I’d stop listening. Instead, check out what all that research has led to in terms of recommendations and lists of known factors that are within your control.

Some factors taken from the [same website include:](https://www.cancer.gov/about-cancer/causes-prevention/patient-prevention-overview-pdq)

Risk Factors

KEY POINTS

Factors That are Known to Increase the Risk of Cancer

* Cigarette Smoking and Tobacco Use
* Infections
* Radiation
* Immunosuppressive Medicines After Organ Transplant

Factors That May Affect the Risk of Cancer

* Diet
* Alcohol
* Physical Activity
* Obesity
* Diabetes
* Environmental Risk Factors – *Being exposed to chemicals and other substances in the environment has been linked to some cancers: Links between air pollution and cancer risk have been found. These include links between lung cancer and secondhand tobacco smoke, outdoor air pollution, and asbestos.Drinking water that contains a large amount of arsenic has been linked to skin, bladder, and lung cancers.Studies have been done to see if pesticides and other pollutants increase the risk of cancer. The results of those studies have been unclear because other factors can change the results of the studies.*

If this list sounds exactly like you’d expect it to, then that’s why it doesn’t make the news very much. Things that “may” be linked to cancer haven’t made the list yet, so I’d focus on reducing risks that are known if that makes you feel better. Neither you nor I are cancer research scientists and probably shouldn’t be making life decisions on studies we can’t really talk about the validity of (*Are their sample sizes big enough? Did that regression work well with the data or should another statistical analysis have been used instead?* And so on.)