Why are they beneficial when we need oxygen to survive? Do they even exist, or is it a marketing buzzword?
In: Biology
Antioxidants have nothing to do with oxygen. Well, it’s unrelated to the molecule at least. An oxidizer is an atom or molecule that accepts free electrons in a chemical reaction, and the most famous oxidizer is, well, oxygen, which is why it’s called that. Oxygen has two free valence electron spots, ready and eager to accept another electron to fill that spot. In fact, the only element that’s a better oxidizer is fluorine. An oxygen molecule has two oxygen atoms that are double bonded, sharing two electrons with each other allowing it to be more stable than it otherwise would be. It’s still not the most stable since each oxygen wants those electrons all to themselves, and this makes it a fantastic oxidizer: it readily accepts electrons from other atoms that don’t care about giving them up. This is basically what fire/burning is, the release of energy as oxygen accepts new bonds that break the double bond it has with another oxygen atom. And in fact, oxygen is such an incredibly reactive and dangerous atom people forget that one time oxygen almost killed all life on earth. Even now too much will kill you. Oxygen is toxic. This all doesn’t really have much to do (directly) with what an antioxidant is.
When oxygen is alone, not in its molecular form, it is a free radical. There are others but in keeping with the naming convention and reality, they are the most common and problematic ones usually. It’s missing those two electrons, and it really *really* wants to get them back. So it’ll try and grab them from anything it can, and that includes your DNA. If it does bond to your DNA, that can cause problems up to and including cell death or cancer. In reality, this is not only oxygen, this is anything that wants to grab electrons off of something, which is called oxidation, and something that does it is an oxidant, or an oxidizer. So an antioxidant does the opposite. It prevents oxidation from happening. It does this by being a reducer, which means it has excess valence electrons. This allows it to “eat up” the free radicals, by encouraging them to bond with it, instead of the stuff you care about. When you eat stuff with a bunch of antioxidants in it, you’re basically preventing the oxidants from hurting you, but beware because too many antioxidants can be dangerous too. They really want to give up the electrons so they can damage you in very similar ways. It’s just that as life forms we produce free radicals all the time as a byproduct of living (breaking up oxygen molecules), we don’t generally produce a lot of antioxidants as a part of living
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