Markham Integrative Medicine
300 Main St Markham North
Markham, ON. L3P 1Y8

Education/Professional Associations:

MD – University of Toronto (1990)
ISOM Medical Education Advisory Board



Dr. John Gannage is the Founder and Medical Director of Markham Integrative Medicine, where he has been advancing the prevention and treatment of chronic disease through nutrition, detoxification, immune modulation and the reduction of oxidative stress since 1998. He has special focus in using biomedical therapies to assist children and families affected by developmental issues, including autism. Dr. Gannage was a principal investigator for TACT (the Trial to Assess Chelation Therapy) and has been administering Chelation Therapy since 1999. He has also received training in Oxidative Medicine and Lipid Exchange Therapy. Dr. Gannage is a Defeat Autism Now clinician, and has completed Modules 1 and 2 of the Medical Academy for Pediatric Special Needs (MAPS) Fellowship training.

Dr. Gannage, holds an active medical licence in good standing with the College of Physicians and Surgeons of Ontario (CPSO). He is a longstanding practitioner of Complementary and Alternative Medicine (CAM). Considered an expert in the field of CAM, Dr. Gannage is often requested to provide his opinion on the current standard of care and best practices within his professional domain. He serves as a Peer Assessor for the CPSO, working on behalf of the Investigations, Resolutions and Complaints Committee, and has acted as a Preceptor for fellow physicians as part of the CPSO’s self-regulating governance and education initiatives.

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Presentation Abstract

Mast cells are a specific type of white blood cell  found in connective tissues throughout the body, especially under the skin, near blood vessels and lymph vessels, in nerves, and in the lungs and intestines. While mast cells play a crucial role in immune function, and are critical for allergy response and protection, disorders involving either the over-production of mast cells or, less appreciated, the hyper-responsiveness of them can be extremely problematic. Patients often present with multiple symptoms affecting many organs. The complexity is further exacerbated by the stimulation of mast cells by many distinctly different triggers, such as medications, environmental exposures, stress and infectious agents. This leads to confusion in diagnosis and management, especially for patients that have neuropsychiatric symptomology associated with other systemic inflammatory complaints. As such, recognition of mast cell instability and mediator release is critical in clinical practice, as is an understanding of measures that can be taken to alleviate symptoms. This is especially important for patients that have been suffering for years and attended upon by multiple health providers across many different specialties, and often dismissed or managed incompletely; and important for clinicians, because many of the interventions can be rooted in functional and orthomolecular medicine.

Contributions to Orthomolecular Medicine

In 2014, Integrative Medicine for Children’s Mental Health was launched. This continuing medical education program was developed by Dr. Gannage, in collaboration with the Canadian Society for Orthomolecular Medicine. The program was accredited by the College of Family Physicians of Canada, and presented throughout 2014, 2015 and 2016, in Toronto, Vancouver, and Calgary.

In 2019, the original program was updated, re-accredited and presented as Nutritional & Environmental Influences on Neurodevelopment.  This program is currently accessible on-demand via the website, and provides an evidence-based approach to addressing ASD, ADHD and other neurodevelopmental conditions. It supports an understanding of  the gut-microbiome-brain axis, oxidative stress, immune dysregulation and the role of environmental toxicants in the development and diagnosis of mental health conditions in children.

Dr. Gannage has also presented seminars for the Orthomolecular Health Public Education Series, and authored articles published in the Journal of Orthomolecular Medicine.


Gannage, J. (2010) Integrative Autism Treatment: Foretelling Medicine’s Future. J Orthomol Med. 25(4)