(208) 385-7711

Dr.Holthouse
Dr. Mark Holthouse, MD, IFMCP
Chief Medical Officer

Meet The FMI Team

At FMI, we’re committed to pioneering the field of functional and integrative medicine. Our focus is on delivering top-quality care to our patients, emphasizing prevention of chronic diseases and getting to the root causes of health issues. We take a team-based and patient-focused approach, where our expert providers work diligently to uncover the underlying reasons behind symptoms. Our unwavering dedication to excellence and patient satisfaction has established us as leaders in the field, setting the benchmark for outstanding healthcare.
Adult Functional Providers
Karen Callagy, PA-C, IFMCP
Adult Functional Provider
Boise Clinic
Julie Franden, DNP, NP-C
Adult Functional Provider
Meridian Clinic
Jacqueline Griffin, MSN, RN, FNP-C, IHP
Adult Functional Provider
Virtual
Gavin Guard, PA-C
Adult Functional Provider
Virtual
Sergey Kashubin, NP-C
Adult Functional Provider
Meridian Clinic
Dr. David Musnick, MD
Adult Functional Provider
Eagle Clinic
Amy Ray, FNP, IFMCP
Adult Functional Provider
Boise Clinic
Shelby L. Stoddard, FNP-C, MS, CCT, FAAO
Adult Functional Provider
Meridian Clinic
Janessa Tenney, PA-C, IFMCP
Adult Functional Provider
Meridian Clinic
Adult Primary Care Providers
Christa Inzer Castillo MSPAS, PA-C, MPH
Adult Primary Care Provider
Meridian Clinic
Kaitlin Cooley, FNP-C
Adult Primary Care Provider
Boise Clinic
Nick Garver, PA-C
FMI Medical Director &
Adult Primary Care Provider
Meridian Clinic
Women's Health Providers
Jessica Bennett, CNM, APRN
Women's Health Functional Provider
Meridian Clinic
Tammy Hadfield, MSN, WHNP-BC, ABAAHP
Women's Health Provider
Meridian Clinic
Pediatric Providers
Dr. Mario Brus, MD
Functional Pediatrician
Meridian Clinic
Aaron Dykstra, DNP, FNP-C
Pediatric Functional Provider
Meridian Clinic
Olivia Mangeac, PA
Pediatric Functional Provider
Meridian Clinic
Dr. Shana Tubach, MD
Functional Pediatrician
Meridian Clinic
Health Coach & Nutritionists
Lois Payne, FMCHC, NBC-HWC
Health Coach
Marianne Green, IFNCP, RD
Functional Nutritionist
Hailie Hermes, RDN, LD, IFNCP
Registered Dietitian

Michael Sermon, PA-C

Michael Sermon is the Medical Director of Functional Medicine of Idaho since 2023. He earned his Bachelor’s Degree in Human Movement Science at Utah State University. He then continued his education at Saint Francis University earning his Master of Physician Assistant Science. While working in family practice, urgent care, and emergency medicine in the rural areas of Texas and Oregon, Michael discovered that lifestyle modification and root-cause medicine is the key to disease prevention and healing.

After experiencing the effectiveness of root-cause medicine in his own life, and the lives of his patients and family, it became clear to Michael that the functional medicine model is key to lifelong health. He believes that patients should be highly involved with their own health care decisions, with guidance and expertise from the FMI team. Michael integrates traditional primary care with functional medicine in order to achieve preventative and restorative care for patients. He is currently working on functional medicine certification.

Michael enjoys hiking, biking, ice hockey, and many other sports. He spends his free time with his wife and children, enjoying the small things life has to offer.

Areas of Expertise:

  • Foundational Functional Lifestyle approach to primary care
  • Cardiometabolic Health
  • Men’s Hormones
  • Autoimmune conditions