How to monetise peoples feeding habits data with consent

I am working with a company that is developing a app that will allow you to check if you can eat food due to various allergies and intolerance's.

They are planning to build a community that is willing to share its food requirement data in return for having food better designed to serve their needs.

They are pondering on how best to monetise that data, auction, straight sale, give it a way....

Anyone got any thoughts or experiences they would like to share...Its a UK company with a global aspiration