The FDA only has jurisdiction over things that are intended to "diagnose, treat, cure, or prevent" an illness. Witness the incredible boom in dietary supplement

The FDA only has jurisdiction over things that are intended to "diagnose, treat, cure, or prevent" an illness. Witness the incredible boom in dietary supplements, (nearly) all of which disclaim exactly the quoted verbiage. (Those that don't disclaim doing those things tend to get a lawyergram from the FDA in short order. See what happened to 23andMe's service a while back as one case in point.)