[MrWookie]

Katy,

DB is right when he's talking about the water soluble vitamins. The flip side of those is that you can't really get too much of them. If you guzzle OJ like a fiend to try and OD on vitamin C or something, your body just passes all the excess out in your urine.

You actually do have to be careful with some of the fat-soluble vitamins, like vitamin A. Since it doesn't dissolve in water, it just hangs out in your body until it's needed. If you eat way, way too much, it can become toxic.

For free radicals and antioxidants, I'm skeptical. Reactive Oxygen Species (ROS) produced by your cells' mitochondria as a normal by product of your metabolism are extremely reactive. Some, like hydroxide radical, will react with virtually the first thing it touches. Fortunately, your body has mechanisms to reduce the output of OH radical and instead put out the less harmful nitric oxide. Still, though, it seems like for antioxidants to have any effect, they'd have to be at a comparable concentration to other things in your cells that these free radicals might react with. Your cells are roughly 200 mg/mL protein, but people take these antioxidants at levels where their concentrations will be, oh, 4-5 orders of magnitude below this. Since proponents say that these antioxidants suck up the ROS directly, they have to be around to bump into an ROS molecule before it reacts w/ something else. If people argue that some of these compounds are stimulating your body's natural defenses against ROS, that I could believe, but I'm skeptical about how effective they are at chewing up ROS on their own.