Competing interests: The BMJ has judged that there are no disqualifying financial ties to commercial companies. The authors declare the following other interests: EIB has acted as a consultant for McKesson Canada for services provided to patients at infusion centres, the Dairy Farmers of Ontario, on health benefits of dairy and how to market dairy, and the Canadian Drug Agency. He has received stipends from Cartrile and Associates, HMP Global, and FusionMD to give presentations on inflammatory bowel disease.