considering the conflicting, uninformed, outdated, and simply erroneous information that many people with PN receive from doctors and other health professionals, there is a general healthy skepticism of professional advice not backed up by studies employing the scientific method.
As an example of medical professionals looking at the same disease and reaching vastly differing conclusions, look at the controversy amongst medical professionals for decades now relating to lyme disease, testing for, diagnosis, treatment, effects, etc. in the same vein,the entire field of supplements is highly controversial even in the face of emerging scientific fact.