Radical!

For years I saw the term 'free radical' bandied about in all sorts of magazines and newspaper articles without having the faintest clue what it actually meant. All I gathered was that they're bad. And they are! (Sometimes.) Here's a quick primer on what they do.

Free radicals are invariably oxygen compounds. The most important thing to understand is that oxygen is a bit of a drama queen. Oxygen is especially attractive to other atoms, and it will do its darnedest to hook itself onto just about anything to form a chemical bond. Why? Well, that's just how it rolls. In fact, unpaired oxygen is so hungry for chemical companionship that it will go so far as to rip away atoms from other molecules. It's the pretty, popular girl who stole your prom date away for half the night, leaving your teenage heart devastated.

Except emotional anguish is nothing compared to what ripping apart a molecule can do to the body. When a free radical attacks a cell, it takes what it wants and leaves the rest of it wondering what the hell happened. Among other things, it destroys the DNA within the nucleus of that cell, meaning it can't just fix itself. The cell is screwed. There's not much it can do now besides keel over and die.

This has its practical applications. Hydrogen peroxide works as an antibacterial agent because of its greedy oxygen component. It's essentially water with an extra oxygen atom, so that extra atom is more than happy to latch on to bacterial cells, ripping them apart and destroying them. It's awfully handy. Free radicals are also present in many of our own biological processes, responsible for breaking down things that actually need breaking down, like waste materials and foreign invaders. We need a decent amount of them to live.

But the bad, evil, scary kind of free radicals that all the magazines talk about are the ones responsible for aging. Over a lifetime of exposure to free radicals, the cells in our body break gradually break down with no hope of repair or replenishment. Fashion mags hate free radicals because they're what makes our skin wrinkle and sag as we get older: they break down skin cells, leaving gaps in our once taut and radiant faces and making the skin more elastic. Health mags hate free radicals because their interaction with cellular DNA can create malignant tumours and other nasty problems. 

Like everything else in our body, balance is key when it comes to free radicals. Too few, and essential tasks don't get done; too many, and we get horrible, horrible diseases. So how do we regulate something that sounds so sketchy? The answer is in antioxidants, another thing we read about all the time without necessarily understanding what it means. To get a rough idea of what they're actually doing, let's go back to the prom metaphor. If a free radical is the mean popular girl determined to ruin the most important night of your life, then an antioxidant is like an intercepting popular dude who sweeps her off her feet before she can sink her talons into your date. (Or another popular girl. God forbid the queer science geek turn heterocentric on her own blog.) Antioxidants are nothing more than molecules willing to be free-radicated themselves, protecting cells in the process. 

Okay, so the correct term is oxidized, not free-radicated. But I like mine better.

(As a mildly interesting side note, and because I know my dad is reading this, I feel compelled to mention that one of my first science fair experiments as a kid was about oxidization. My dad and I put all kinds of crap on sliced apples to see what kept them from browning. And why do apples brown? Because oxygen atoms in the air act as free radicals and destroy the apple cells from the outside in, killing it slowly and painfully. I didn't quite get that far in my thinking in Grade 5, despite Dad's best efforts, but now I think I get it.)

Humans don't naturally produce all the antioxidants we need, so we have to add them to our diets. And that's where vitamins come in. Vitamins C and E are especially good antioxidants, and they're found mostly in fresh fruits and vegetables (or candy-flavoured tablets, if you really can't stand spinach). There are also great chemical compounds in things like tea, coffee, soy, red wine and chocolate that act as antioxidants, which is why you have all these smug bastards gloating about how their doctors told them to drink a glass of wine every day and eat more (dark!) chocolate. You might want to focus more on the vegetable side of things, though, unless you've been really dying to break in your copy of Wii Fit.

So, free radicals: good, bad, and totally destructive, like a sexy prom queen on a monster truck. And you'd better believe that's what I'm writing on my midterm.