Fitbit isn't the only one interested in a built-in blood sugar monitor. Reports surfaced early last year that Apple was working on one itself, but while Sano's product uses tiny needles to take its measurements, Apple has reportedly been chasing a device that has so far proved unattainable -- a non-invasive, continuously monitoring device. For Fitbit, working this kind of feature into its products could be a smart move as some of its competitors have started to move past them in the wearables field. While Fitbit previously dominated the market, it lost quite a bit of market share to Apple and Xiaomi last year, both of which took turns leading the market last year, quarter to quarter.

Park stopped short of saying future Fitbit devices will have built-in blood sugar monitors, naturally, but this investment shows the company is at least interested in that direction. Sano's tracker won't be available to consumers for at least another year.