That web site is the U.S. National Library of Medicine National Institutes of Health web site. It indexes articles irrespective if they are good, bad or otherwise. If you do a search using "soy AND thyroid" you will notice that many of the articles refer to research on mice, rats, dogs and other animals. These results cannot be translated to similar effects in humans. You might check with your GP or an endocrinologist who can enlighten you more about the accuracy of what you are being taught.
What is the name of school at which you are taking your naturopathy course?
-------------------- STABLE: ♂, IBS-D 50+ years - Science of IBS