Tim Cook's New Accessory: An Apple Glucose Monitor? CNBC on Thursday reported that Apple CEO Tim Cook was spotted at the company's campus wearing 'a prototype glucose tracker on the Apple Watch.'

Evidence that Apple is working on a product for people with diabetes is mounting.

CNBC on Thursday reported that Apple CEO Tim Cook was spotted at the company's campus wearing "a prototype glucose tracker on the Apple Watch." The news outlet reckons the device -- should it actually come to market -- would be a "'must have' for millions of people with diabetes."

The rumor comes after CNBC last month reported that Apple had hired a "small team of biomedical engineers" who are working out of an office in Palo Alto, Calif., to develop a "holy grail for treating diabetes." The "super secret initiative" -- planned by the company's late co-founder Steve Jobs -- aims to "develop sensors that can noninvasively and continuously monitor blood sugar levels to better treat diabetes," according to the report.

Though the Cupertino tech giant is generally ultra tight-lipped about new products in its pipeline, Cook may have hinted about a possible Apple diabetes product in February. Speaking with students at the University of Glasgow in Scotland, where he received an honorary degree, Cook said he'd been wearing a glucose monitor for "a few weeks." He didn't say whether it was an Apple prototype or a device from a different company, however.

"It's mentally anguishing to stick yourself many times a day to check your blood sugar," he said, according to CNBC. "There is lots of hope out there that if someone has constant knowledge of what they're eating, they can instantly know what causes the response... and that they can adjust well before they become diabetic."

PCMag's Tim Bajarin, who has diabetes, argued in a recent column that if Apple tackles this area, a real breakthrough would be an affordable, non-invasive and accurate solution. He uses Dexcom's Continuous Glucose Monitoring (CGM) and says "it has changed the management of my diabetes for the better." But it requires a sensor on his stomach and two small, hair-like wires that get blood sugar readings from an interstitial fluid just below the skin every five minutes.

Monitoring via light pulses or sensors on a wrist band or watch, like Apple Watch, would be less invasive, but accuracy is still an issue.