Clinical trials would be required, depending on the strength of the claim. The understanding with the natural health products regulations is that the level of evidence required is based on the strength of the claim. So if you're making it a structured function that basic calcium helps build strong bones, you can rely on textbooks, for example. If you want to go beyond that and start talking about treatment of cancer, for example, you would most likely need clinical trials. The concern now is that the NHPD is not looking at that broad range of evidence.
On May 8th, 2008. See this statement in context.