Well, here's the thing, and this is just my perspective, but I think a lot of narrators will agree, breath sounds are only bad when they are pull the listener out of the story. Heck I use breath sounds to convey information from time to time, a snort, a hiss, a long breath, they all offer communication to the listener.
That said if you are doing technical reading and they want captain robot to read the material then I would suggest backing off the mic a bit, making sure it's up and out of the way of your airflow, their's no really effective way in audition (or any other program really) to automate breath removal, though you asked about reduction now that I think about it. Well, some folks would just use a noise gate but it always feels a little weird to me when you listen and then it goes to complete silence between speaking.
Some folks who use gates actually sample a background hum (of about -48db if I recall, anybody use that technique? speak up?) and mix it into the track to avoid that drop off feeling when using a noise gate.
Been awhile for me on that though....
Just saw Joe Pike's post, let me know how that works out?
Tobias, I agree with you. Breaths are not always bad. They can help communicate emotion in a read sometimes. Listen to singers on the radio and you'll hear inhales on many phrases - and sometimes you won't. Often, a breath can be acceptable if it connects two sentences in a flowing thought. But they can also be distracting, such as at the beginning of a paragraph. So step one is to make sure you have a very quiet room so you can keep your noise gate at a minimum, allowing for breaths to be heard when they are a natural part of your phrasing, but silencing your breaths when you pause and inhale slowly and quietly. If the noise gate is set too high, it can suddenly "open" in the middle of an inhale clipping the breath and necessitating an edit. Setting the "attack" to slow should help this but I have found it doesn't always eliminate the problem. So it is a combination of breath control (train yourself to inhale quietly - moving back from the mic when you do), minimal noise gate, good room acoustics, and interpretation of the script. If you need to, a bit of "room tone" will cover a breath very nicely. Hope this helps!