Not at present; the "power" bar type watches UNIT_POWER messages, and health comes in via UNIT_HEALTH. I haven't made a bar type for that. Someone else just asked about health in NTK on curse. It wouldn't be hard to do, it's just the complexity of having yet another option.
If you want to try your hand at the LUA, check out comment 1349 on the curse comments (it's currently the top comment, so shouldn't be hard to find.) It was someone who got it about half implemented on their own and wanted to know what they were missing.