system
Given the following post, respond as if you're commenting on Reddit:
human
What do heavy metals really do to a person, and what does our body do to get rid of them?

There’s been plenty of misinformation spread thanks to the vaccine scare, so I’m curious to have some facts. 

Let’s say some unfortunate person has eaten a tomato with an amount of lead in or on it. 

The symptoms of heavy metal poisoning are easy enough to find online, but what exactly is happening to cause the symptoms? It’s usually a bad thing to have them around in the body, so what does the body do to remove them? Are they just filtered out by the kidneys like a lot of other stuff? Do they break down somehow on their own?
gpt
Like people have suggested 'heavy metals' is vague so in general: proteins are constructed from amino acids basically small Carbon/Nitrogen molecules, however each type of amino acid has a specific molecular group (functional group) attatched onto the side of it (ie Glycine has just a hydrogen and methionine a Sulphur, Carbon and 3 Hydrogens). Proteins are folded into a very specific shape based on these groups due to the interactions between one another. There are likely 100s or more of these interactions that fold each protein, it's shape is integral to its function. One type of interaction between these functional groups is known as ionic ie. proteins bound to metals such as sodium, zinc, magnesium, potassium which the protein requires to perform specific tasks. Ie zinc finger protein in DNA regulation. However heavy metals can bind instead, disrupting functionality or alter the structure of a protein entirely.

Heavy metals can also bind to RNA and DNA meaning they not only effect protein synthesis and intracellular signalling of RNA, but also lead to carcinogenesis (binding to nucleic acids causing dysfunctional DNA replication). Remember DNA = Deoxy-Ribonucleic Acid.


So different heavy metals bind with different proteins (depends on frequency of amino acids present it can bind in that particular protein or how its folded and therefore what functional groups are exposed) heavy metals can also bind DNA which causes carcinogenesis. They can be excreted or sequestered differently within the body (this changes from human to human) which  affects its effects*. If you ingest mercury your gums will get sore and you'll get diarrhoea, however Cadmium will cause lung inflammation. These are acute symptoms, chronic would be cancer, neurological issues etc.

Edit: Cysteine to Glycine (been a few years).
Edit2:*

Also note Iron is also considered a heavy metal yet essential to our diet. Excretion of HM is quite a massive topic.