I agree with you Stephen, you are targeting a very different market that also requires a deep underestanding of the human intervariability and how the nutrition affects in each case.
I think that price sensitivity is closely related with the country, actually in Spain, people spend more money in fitness (crossfit, gym, running, etc) than in healthcare (mainly because we have a public healthcare system that covers main diseases, and people is not used to pay for healthcare). But I also agree that low-price is essential for a home-care device.
Hmm, well, the research group we are working with is developing sensors for magnesium. The regulatory aspects for your market are much softer than medical devices ones. The problem is that we don't have the knowledge to develop a product in a market where we don't have experience. Could you describe me in a more detail your chunk of marketplace?