I'm only going to try to address the question of DC fields.
Medical MRI uses uniform fields of about 0.5 to 3.0 T. In a head MRI, the Lorentz force on ions in the brain can cause neurological effects such as vertigo. I've heard that this shows up in particular when the patient moves his head.
Here is a famous picture of a frog being levitated by a 16 T magnetic field. This effect requires a nonuniform field; a diamagnetic object is attracted to a region of lower field strength. I've always assumed the frog was unharmed, but I don't know for sure.
Based on this, it sounds like the result depends on whether the field is uniform or nonuniform.
Short answer: No.
The iron in the body is not magnetic because it is not in metallic form nor magnetite form. It is instead an ion complexed to nitrogen atoms in turn bonded to proteins.
The human body repels magnets very slightly because it has water, which is diamagnetic. Powerful enough magnets have been used to make frogs float, but unfortunately only small objects can be levitated this way.
Diamagnetic materials will seek out regions of lower field strength. The diamagnetic acceleration goes as B*dB/dx, where B is the magnetic field and dB/dx is the gradient. Larger objects need more total B because the B gradient must persist over a longer distance. Because the force is B*dB/dx and not dB/dx, the maximum B required follows a square-root field strength scaling law. For a human, ~25 times larger than a frog, you will need a field 5 times as intense. Ten tesla will levitate a frog, so 50 to for a human. 45 is our limit (national high magnetic field lab) for now. It requires megawatts of power for the resistive inside, liquid helium for the superconductive outside, and probable lots of care to make sure the whole thing doesn't explode due to the magnetic forces. In the future, it is not infeasible that we will produce 50 tesla, but it would probably have a small bore/coil size ratio.
Far more important is that 10 tesla MRI will make a person quite dizzy. The vestibular system (ear motion detector) runs a DC electric (ionic) current through a fluid. If you put this in a static magnetic field, you will get a Lorentz force, which will swirl the liquid. If you rotate in the field, other magnetic effects on conductors would apply as well. 50 tesla would be much harder, if not dangerous.
The shape is also important. You would need to build a static machine so that you can sit or stand in the "gravity", but you can't walk around.
Finally, your magnet would attract ferromagnetic projectiles with 25 times the force of a 2T MRI. Shrapnel!
Lets stick to rotating space stations for now.
Best Answer
I don't know much about the topic, but here are some research points you can get started with.
For strong magnetic fields, the most notable effect seems to be visual effects (source), called phosphenes (magnetophosphenes in the specific case of magnetic causes) caused by inductance of electric currents in the retina (source).
"Studies" seem to have suggested that 50T fields cause tissue damage, for unspecified reasons (weak source). I could not locate these studies. However, the implication is that immediate death / severe damage is not caused at even 50T fields (for reference, MRIs generally run in the 1.5-3T range).
There are related questions here:
There is an interesting discussion on Reddit:
There is also a field of study called bioelectromagnetics dedicated to biological effects of magnetic fields, which can serve as a good starting point for research:
"Transcranial magnetic stimulation", referenced in both the Reddit and Wikipedia pages, uses small fields in the range 1-10mT to affect the polarization of neurons in the brain.
It seems that the pattern of change of a magnetic field has a more pronounced effect than the strength of the field. Static fields do significantly less (or no) damage, while at high frequencies a weak magnetic field could certainly do significant damage, e.g. a microwave oven.
Primary causes of damage from non-static fields mostly seem to be due to heat, or due to induced electrical current; for example, from the ReviseMRI link above:
It would doubtless take an extremely strong magnet, higher than anything we could produce, to pull the iron out of your body (conjecture, no source). Note also that there is only about 3-5 grams of iron (something like 2 cm3) in the human body (source, unreferenced source), mostly bound to hemoglobin.
Count Iblis pointed out, in question comments, that there is a nice discussion of magnetars and strong magnetic fields here, which provides nice overviews and plenty of interesting information (although a bit dated):
From there:
As for long term effects of more commonly encountered field strengths, there is generally little association between magnetic fields and cancer (source, source).
I hope this helps. Sorry I do not know a direct answer. It certainly depends on more than just the field strength, however.