eli5: If tobacco is a leaf, why does it have so many substances known to cause cancer?

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* Source is the packaging I’ve just read for a pack of tobacco in the UK which says it has 70 cancer causing substances

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42 Answers

Anonymous 0 Comments

It has other additives, but generally burning things and inhaling the smoke is bad as well.

Anonymous 0 Comments

It has an insane amount of chemical additives, probably varies between brands and countries but in the UK there are 600 different permitted additives, sugars, moisturisers, pesticides, heavy metals etc. These are used for reasons such as flavour enhancement, protecting the plant when growing, and prolonging the shelf life of the cigarettes.

Anonymous 0 Comments

Plants make all kinds of weird chemical compounds to make them poisonous and prevent them from being eaten by bugs and deer and things like that. Those compounds do things to the body. Plus when its burned chemical reactions happen that change the structure of a lot of it into other things, which are harmful.

Anonymous 0 Comments

Nicotine, the active ingredient in tobacco, is created by the plant to prevent things from eating it. Often irritants to insects and animals (yes, insects are animals, but they’re important to point out in particular) end up being cancer-causing both because of how they irritate, and because the more damage they do the more likely the predator is to avoid the plant either by learning or through evolution.

Also, generally tobacco is smoked, so any warning related to its chemical composition will be in the context of those chemicals entering the lungs. Generally most chemicals are dangerous in the lungs: people who inhale soot from a house fire are also at a higher risk of cancer. Since tobacco is usually smoked, even if you’re not buying a smokeable version, the testing for if the chemicals are cancerous was likely done regarding cigarettes. (This doesn’t mean that there’s no risk, though. Chewing tobacco is still known to increase the risk of cancer.)

Anonymous 0 Comments

A lot of the carcinogens are produced by burning the leaves rather than just existing within the leaf on its own.

You’ll get things like tar and soot which are carcinogenic if you burn other natural materials like wood or tree leaves too – it’s not unique to tobacco.

The main differences with tobacco are the frequency with which people burn it (multiple times daily whereas most people wouldn’t have a bonfire even weekly); and the way people deliberately inhale the smoke deeply to get the effects of the nicotine in their body.

Bringing the smoke into the lungs on purpose means that carcinogens which you’d usually need to be exposed to in much larger quantities on, say, your skin for them to cause cancer can act more directly on the delicate lung tissue.

Anonymous 0 Comments

It has other additives, but generally burning things and inhaling the smoke is bad as well.

Anonymous 0 Comments

It has other additives, but generally burning things and inhaling the smoke is bad as well.

Anonymous 0 Comments

It has an insane amount of chemical additives, probably varies between brands and countries but in the UK there are 600 different permitted additives, sugars, moisturisers, pesticides, heavy metals etc. These are used for reasons such as flavour enhancement, protecting the plant when growing, and prolonging the shelf life of the cigarettes.

Anonymous 0 Comments

It has an insane amount of chemical additives, probably varies between brands and countries but in the UK there are 600 different permitted additives, sugars, moisturisers, pesticides, heavy metals etc. These are used for reasons such as flavour enhancement, protecting the plant when growing, and prolonging the shelf life of the cigarettes.

Anonymous 0 Comments

A lot of the carcinogens are produced by burning the leaves rather than just existing within the leaf on its own.

You’ll get things like tar and soot which are carcinogenic if you burn other natural materials like wood or tree leaves too – it’s not unique to tobacco.

The main differences with tobacco are the frequency with which people burn it (multiple times daily whereas most people wouldn’t have a bonfire even weekly); and the way people deliberately inhale the smoke deeply to get the effects of the nicotine in their body.

Bringing the smoke into the lungs on purpose means that carcinogens which you’d usually need to be exposed to in much larger quantities on, say, your skin for them to cause cancer can act more directly on the delicate lung tissue.