Effects of a very large magnetic field on the human body

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.

One simple approximation that you could make is to assume that the human body is made of water. Then you can reduce your question to: what happens to water molecules in a magnetic field. Consequently, you would have to ask how you can break the Van der Waals Bond in water with a magnetic field.

I think here you would have to differentiate between a static or dynamic magnetic field. For instance, a 10 T static magnetic field can levitate water molecules, but is it enough to rip them apart?

If you apply some sort of dynamic EM-field, for instance in the microwave range, you can heat up the molecules, which is the working principle of the microwave oven.