Working at the NIH gives you valuable biomedical research experience. If your app is centered on how you want to do biomedical research and be a physician-scientist, then doing that work at the NIH strengthens your credentials (you might even get a publication out of it, which is impressive). But if your application is centered on how you want to help the poor, then working at the NIH might not really help you that much and seem like you're just checking off boxes.
The NIH also has research groups that work on health disparities, addiction research, AIDS/HIV relief, and other public health projects. The Department of Bioethics also has its own predoctoral fellow program which allows students to work on the clinical research service while doing research under a bioethics mentor (lawyers, philosophers, social scientists, nurses, and physicians). So, while most available positions will be in the laboratory setting, there are a lot of opportunities at the NIH for those who are not exclusively interested in basic science!
I was not originally planning on working at the NIH, but when I saw their health disparities department I got super excited! My only worry is that I am applying to medical school once I graduate from my undergrad next year, so I would only have 1 year to work there if I was fortunate enough to be accepted. However I've heard that most places want a 2 year commitment. How feasible is it to get a 1 year gig, and is there anyway to increase the likelihood of this happening?
It all depends on the PI and group you want to work with. If you are planning on only taking 1 year off, it will be more challenging to find a PI that can accommodate you but it is certainly possible.
So is the only way of knowing that just applying to a bunch of labs or is there a more efficient way of figuring this out. Also in my situation, would you recommend including that up front in my cover letter, or only including that in an interview if I was fortunate enough to get one?
If there is a more efficient way, I do not know it. @Lost In Transcription might know. I would personally discuss it in the interview, but if you mention it in the cover letter then you will only get responses from people who are looking for a 1 year commitment and that makes the expectations clearer for you and the PI