The answer is, yes, candida will eat the oat bran. But then, candida can eat almost anything that you can put into your mouth. The key is that oat bran is a better food for the benefical bacteria than it is for candida.
So..
Candida diet (no sugar, no simple starches, etc.)
Plenty of fiber to feed the benefical bacteria (oat or rice bran)
Suppplementation with probiotics (kefir from grains, fully fermented yogurt, capsules)
By following the above suggestions, you have created a conditon in your gut that favors the growth of beneficial bacteria over that of candida. Given time, the beneficial bacteria will multiply to the point where they naturally control the candida.