A UK start-up hopes to offer in-store DNA tests at top supermarkets, to help people eat more healthily.

The retailer Waitrose told the BBC it was “exploring” the idea, but geneticists question the thinking behind the proposal.

The tech will be one of many health-related innovations on show at the CES tech trade fair in Las Vegas next week.

Read our giant preview of the tech expo and see more hands-on videos