I would follow the food pyramid, like on cereal boxes or bread. Also multivitamins, and water. ALSO, omega oils like fish oils from fish, fish oil pills, flax seed oil or flax seed meal. Another omega oil is linoleic acid, from saflower and soybean oil. ALL These oils dont FIT into my reular diet but they are suppose to be REALLY good for U. U can find them in the food supplement/ healthy food section of stores. I forgot the recommended dosages. Personally, Flaxseed meal and fish oil pills have been the best options for me.
I also take lots of vitamin A, from carrots/ carrot juice--about a cup a day. I beleive a form of viamin A is in the acne drug accutane but in a highly concentrated, synthetic form. I dont remeraber what the upper limit of vitamin A is to be toxic, but I think too much for too long is bad.(Thus, the many side effects of accutane) Too much of ANY vitamin is usualy toxic.
Im not sure how much these ACTUALLy help keep me from breaking out, but I'm a little superstitious and stick with what has WORKED for me.