Before the word integrative medicine was popular or even existed, other words such as holistic medicine, complementary medicine, alternative medicine, and complementary and alternative medicine was popular. Andrew Weil, MD who is widely regarded as the pioneer of integrative medicine, popularized the use of the term and academic medicine and health systems quickly adopted the term. Today, many of strongest academic medical centers and many of prominent health systems offer integrative medicine programs. Many of practitioners undergo training through University of Arizona.
Functional medicine was developed by Jeffrey Blands, PhD a biochemist who focused on the enhancing plausibility biochemical mechanisms which later exploded to include genetic testing, epigenetics, organic acid testing, micronutrient testing. Previously most practitioners underwent training through Institute of Functional Medicine (IFM) Today there are other programs which are taught by graduates of IFM.
Integrative Medicine is still the preferred term for most of the academic medicine and health systems, but there are signs of institutions beginning to embrace functional medicine including Cleveland Clinic.
To me, good Integrative Medicine and Functional Medicine share lifestyle medicine as a commonality. There are some differences in that functional medicine relies more on testing while integrative medicine focuses on mind-body medicine and integration of whole system healing such as Chinese medicine.
The important commonality is that both help patients to solve their problems that are resistant to treatment with conventional medicine. To me, I have had operated Integrative Medicine where I did no functional medicine testing, and I have had operated in Functional Medicine environment where there was all the testing that was available. Today, I have found a happy medium where I utilize some test to ask questions and explore potential explanations behind patient's symptoms. Some call this approach root cause of disease. For example, micronutrient testing allows for me to assess patient's nutritional status - there is direct method where one can measure the micronutrient level directly and indirect method of assessing metabolism by measuring metabolites. Both techniques have validity and limitations. For environmental and food allergy, testing is needed so that immune system can be desensitized in a safe manner - which addresses the root cause of allergy. Other tests help to determine cause of fatigue, lack of libido through measuring hormones in saliva and/or urine (blood, too). GI labs are invaluable in assessing functional health of digestive system.
I think the most important thing to remember is that we need to treat the whole person - not their labs. My role as a responsible physician who practice integrative medicine and functional medicine is to guide patients to the minimum number of tests to answer as much questions as possible. There are many stories of functional medicine causing financial hardship and toxic financial conditions.
This is the reason for my creating a direct care integrative and functional medicine clinic.