Dr. Holthouse
IFM Certified Practitioner

Mark Holthouse, MD, Medical Director

Dr.  Mark Holthouse joins FMI as our new Medical Director. He graduated from Loma Linda University School of Medicine and went on to obtain his Family Practice training at UC Davis Medical Center while in the Air Force Scholarship program at David Grant Medical Center, Travis AFB.  “Dr. H” has many years of family practice experience and also brings years of practice in the areas of Functional/Integrative Medicine. As part of the Institute for Functional Medicine teaching faculty, he has educated thousands of practitioners in hormone health across the nation over the past 7 years.  Dr. Holthouse is part of the teaching faculty at Loma Linda School of Medicine, where he teaches cardiometabolic prevention and reversal of diseases like type 2 diabetes, heart disease, high cholesterol, obesity and metabolic syndrome. In addition to his clinical and teaching experience, Dr. H has 28 years of owning his own private practice as acting medical director implementing strategic models in clinical practice and the business of Functional Medicine. Dr. Holthouse and his wife Tammie enjoy photography, anything to do with snow sports, sailing, hiking, kayaking and good food of course!

* Dr. Holthouse will begin seeing patients in April.

Dr. Brus

Mario Brus, MD, Functional Pediatrician

Dr. Mario Brus obtained his medical and pediatric specialty training at Loma Linda University in Southern California. He is a board-certified pediatrician and maintains his Fellow of the American Academy of Pediatrics (FAAP) designation with his ongoing commitment to lifelong learning and advocacy for children. His current emphasis is pediatric functional medicine, which aims to find underlying causation for pediatric chronic conditions. He addresses the root cause of these conditions with appropriate laboratory testing, genetic testing, and by emphasizing lifestyle and nutrition changes, as well as appropriate nutritional supplementation. This functional approach to pediatrics allows Dr. Brus to partner in the care of your child by listening to your concerns and making your child’s health his primary focus. He believes in a conservative use of drugs and an aggressive encouragement of lifestyle and dietary changes that strongly impact body and brain function. Overall, his goal is to fix health issues at their source.

Dr. Hudson

Jennifer Hudson, DO, FACOG, Functional Women’s Health & OB/GYN

Dr. Jennifer Hudson obtained her medical degree from Virginia College of Osteopathic Medicine and completed her residency training in OB/Gyn at Wright State University/Wright-Patterson Air Force Base in Dayton, OH. She is a board certified OB/Gyn specialist through the American Congress of Obstetrics & Gynecology. For her functional medicine training, she has completed the Kresser Institute’s ADAPT Framework Level One course and plans additional certification through the Institute of Functional Medicine in the near future. She transitions from a busy local conventional practice to pursue professional goals in assisting women of all ages in their quest of optimizing health and promoting healing by identifying root cause of symptoms. Her interest in Functional Medicine started with her own journey to get healthier in preparation for pregnancy, and she continues to reap these rewards every day in her own life and that of her family. She provides full spectrum OB/GYN care with an integrative and holistic perspective; her favorite clinical interests include fertility, natural birth, lactation, family planning/contraception, menstrual disorders, and minimally-invasive gynecologic surgery. She also supports women through the menopause transition, focusing on using the functional medicine philosophy to help balance hormones and prescribes bioidentical hormone replacement when appropriate. Dr. Hudson boasts an extremely low cesarean rate and loves partnering with local doulas to foster the beautiful process of childbirth in a hospital. At this time, Dr. Hudson is only seeing women’s health and OB patients. For primary care and general functional medicine needs, please seek a consult with one of our adult functional medicine providers.

Amber Warren
IFM Certified Practitioner

Amber Warren, PA-C, Adult Functional Practitioner

Amber received her Masters in Physician Assistant studies from Midwestern University. She has completed the educational requirements for the Institute of Functional Medicine and is a fully certified functional medicine practitioner. She started her career in orthopedic surgery, appreciating anatomy and physiology, but ultimately had a desire to investigate the body as a whole. She eventually moved into the field of rheumatology, fascinated by the immune system and chronic disease management. It was in this space that she started to investigate the immune system’s interaction with environment, and the root cause of autoimmune disease- alterations in the microbiome. Passionate about nutrition, she started to implement “food as medicine” with her patients, and saw dramatic improvement in symptoms, and ultimately a reduction in the need for pharmaceuticals. A career in functional medicine has allowed her to incorporate everything she believes is needed to heal the body. Outside of her career, Amber enjoys mountain biking, skiing, and anything in the outdoors with her three boys and husband.

Karen Callagy

Karen Callagy, PA-C, Adult Functional Practitioner

Karen received her Bachelor’s degree in Kinesiology from Pennsylvania State University in 1997. After working in Physical Therapy, as a PTA for several years, she went on to obtain her M.S. in Physician Assistant Studies at Arizona School of Health Sciences in 2005. She began her PA career in Family Medicine, eventually transitioning to Urgent care, as well as a brief stint in Oncology. In all these settings, she began to realize that prescribing medications was not enough to make patients better and in many cases only perpetuated the problem. In her personal life, she was dealing with family members with autoimmune diseases that conventional medicine could not help, because diet was never addressed. After discovering the Institute of Functional Medicine in 2014, there was no turning back. Not only has she helped her own family but innumerable patients with the help of IFM. She continues to work towards her IFM certification, specializing in thyroid and gut health. Karen firmly believes in “mind, body and spirit” and that each of these aspects must in balance for her patients to achieve their maximum health potential. She immensely enjoys going on the journey to wellness with her patients and believes it “takes a village” to accomplish this, ie. Nutrition staff, life coaching, and in some cases counseling. In her personal life, she enjoys outdoor activities with her husband and 3 children, on the mountain where they reside, with their bunnies and Bernese Mountain Dog.

Amy Ray

Amy Ray, FNP, Adult Functional Practitioner

Amy Ray is board certified by the American Nurse Credentialing Center as a Family Nurse Practitioner. Amy has over 17 years of healthcare experience and is passionate about seeking out the root causes of chronic “dis-ease” and empowering her patients to reach and maintain a state of optimal wellness. She has her undergrad in Nutrition Science from UC Davis and her Master’s degree in Nursing from MGH Institute of Health Professions in Boston, MA. She first started looking in to functional medicine after many years of being disillusioned with allopathic medicine when her chronically ill patients rarely ever felt better with conventional treatment. She became fully committed to functional medicine after her father was diagnosed with stage 3 chronic kidney disease and was told he would be “monitored and then treated when it got worse- and it would get worse.” Luckily, he was not satisfied with that answer and came to her for help and guidance using her new found functional approach. He is at is healthiest now, and she has never looked back.  Amy has extensive experience in metabolic syndrome, insulin resistance, hormone imbalance, gut health, headaches, and autoimmune issues.  She truly believes that food is medicine and that lifestyle changes are foundational for reversing chronic “dis-ease”.  She believes our bodies are incredibly smart and protective and seeks to partner with her patients to find ways for their unique bodies to find the wellness and balance they once knew. She is currently pursuing certification in functional medicine from the Institute of Functional Medicine. Outside of the office, Amy enjoys fitness, volunteering, gardening, traveling and all things outdoors. She and her husband moved to the area in hopes of enjoying all the wonderful outdoor opportunities Idaho has to offer.

Teresa Gabiola-Shelton

Teresa Gabiola Shelton, PA-C, Adult Functional Practitioner

Teresa earned her Masters in Physician Assistant Studies from Idaho State University. She spent several years as a family practitioner in Utah and Idaho, then began working in Men’s Health, Women’s Health, Age Management, and Integrative Medicine. Through continued education at A4M, she’s rediscovered new tools to treat causes of illness, which took the focus away from treating symptoms and instead placed that focus on the entire person. Teresa focuses her practice on metabolic dysfunction and diagnosing and treating hormonal imbalances. She is well versed in using bio-identical hormone therapies. Additionally, she specializes in using intravenous nutritional therapy to treat and prevent a wide variety of chronic illnesses. Her goal of returning control to the hands of the patient and empowering them to find their best health, in Teresa’s experience, is best reached with the therapies of both functional and traditional medicine. She is excited to return to family medicine at Functional Medicine of Idaho and is proud to become a member of this dynamic team. Teresa looks forward to learning about you and your health goals, and to working together to help you feel your best. In her free time, she enjoys getting outside with her two sons and husband, attending events at the Basque block, and getting grubby in her garden, then cooking her native foods for a full house.

Mikayla Todd

Mikayla Todd, FNP, Adult Functional Practitioner

Mikayla Todd is passionate about helping people THRIVE. She is dedicated to seeing people live a VIBRANT life from their insides to their outsides. She is acutely aware that a vibrant life encompasses the whole person. She is determined to see people heal from disease at the root along with preventing future harm.  Mikayla Todd is a Board Certified Family Nurse Practitioner with specialized training in Functional Medicine through the Institute of Functional Medicine. For the past several years, Mikayla has been practicing at a family practice in San Diego watching people heal from many autoimmune disorders and “irreversible” chronic diseases including but not limited to plaque psoriasis, diabetes, hypertension, various thyroid disorders, PCOS, concussion syndrome, a myriad of gut disorders, and infertility.  She also loves to incorporate genetic testing when applicable. Returning to her hometown in Boise, Idaho, Mikayla is honored to practice at Functional Medicine of Idaho, where she gets to live out her dedication to wholeness through the lens of Functional Medicine. Mikayla believes that with optimal health fully restored, people are able to more fully invest in their one life, the people they love, and the community around them.


Leanna Moser, FNP, Pediatric & Adult Functional Practitioner

Leanna is a board-certified Family Nurse Practitioner. She has a passion for helping others achieve health and wellness by offering the entire spectrum from natural to modern medicine. Her particular interests include pediatric care, thyroid and hormone balancing, diabetes, anxiety/depression and cardiovascular health. With a firm belief that mental, spiritual and physical health encompasses the whole person, she seeks to offer compassionate individualized care through an open provider-patient/parent relationship. While she received medical training from Walden University and thrives on continuing her education in modern and natural medicine, she also has a niche and enjoyment in aesthetics and helping patients to feel better from the inside out! She has been in family practice for 4 years with a background of 15 years experience in Emergency/Trauma, Women’s Heath/Obstetrics and Aesthetics in California. Leanna moved to the Treasure Valley four years ago with her husband, four children and two dogs! They enjoy being active outdoors and in their community, love time spent with friends/family, and in their church and faith.


Jessica Bennett, Certified Nurse Midwife/APRN

Jessica graduated with a Bachelors of Science in Nursing from the University of Vermont in 2003. After practicing as a nurse for ten years, she felt an unwavering desire to continue her education and pursue an advanced practice degree as a Certified Nurse Midwife. Graduating with honors from Frontier Nursing University in 2014, Jessica set out as a Certified Nurse Midwife and has never looked back. Over the past five years, Jessica has provided women’s health primary care, with a particular emphasis on hormone imbalance, including thyroid conditions, PCOS, infertility, sexual pain, and hormone replacement therapy for pre-menopausal and post-menopausal women. She is also experienced in full-scope well woman/primary care, including natural childbirth, birth control consultations, family planning, IUD and Nexplanon insertions and removals, GYN annual exams, problem visits, medication management, thyroid issues, hormone balancing, gut health, natural approach to managing mood disorders, and diet and exercise management for weight loss. Her approach to women’s healthcare is focused on prevention, total body wellness, and patient education. With a true passion for health, wellness, and empowering women, she is immensely grateful to have the opportunity to pursue her passions every day.

Nutritionists & Health Coaches

IFM Certified Practitioner

Tom Malterre, MS, CN, Director of Nutrition Education

Tom Malterre joins FMI as the Director of Functional Nutrition Education. Tom began his fascination with nutrition at the age of 10 where his family doctor, Dr. John McDougall, taught him the importance of using food for medicine. Since then, Tom has achieved both a Bachelor’s and Master’s degree in Nutritional Sciences from Bastyr University and advanced training from the Institute for Functional Medicine. He is a current faculty member of the Institute for Functional Medicine (IFM) and has lectured across North America for IFM, Thorne Research, and The Autism Research Institute. Tom spent 7 years as a member of the medical affairs team at Thorne Research where he lectured on the nutritional biochemistry of vitamins, herbs, and supplements. He is the co-author of The Elimination Diet Book, The Whole Life Nutrition Cookbook, and the Nourishing Meals Cookbook. For the last 8 years, Tom has been educating practitioners about the foundations of functional medicine including diet, detox, digestion, dietary supplements, and functional lab analysis. Tom has worked at VIOME where he educated on the importance of a healthy microbiome, he has given a TEDx talk about detoxing with broccoli, and has worked with a team at MIOS health to develop a lifestyle program for Alzheimer’s disease. In his spare time, Tom loves to hike, harvest wild mountain plants, snowboard, rock-climb, and skateboard with his children.

Tamra Gyrek

Tamra Geryk, RN, Integrative Nutritionist

Tamra is a Functional Medicine Registered Nurse, Nutritionist and Health Coach. An educator at heart Tamra is passionate about creating change in how health care is provided and perceived. She is currently pursuing her certification through the Institute of Functional Medicine, specializing in detox, brain health and cardiometabolic health. She has completed all of the Institute of Functional Medicine training modules. Tamra earned a Bachelors of Science in nursing from the University of Massachusetts, Amherst and completed their accelerated second bachelor’s nursing program. She completed her Masters of Science in exercise science specializing in health promotion, disease prevention and behavior modification. During her graduate studies she completed her field work at Canyon Ranch in Lenox, Massachusetts and her Health Coaching Certification through the Institute for Integrative Nutrition in NYC. Tamra’s journey into functional medicine began while seeking root cause medicine to address her own digestive and energy imbalances over 15 years ago.

Alexis Villaret

Alexis Villaret, Functional Nutritionist

A native of Las Vegas, Alexis completed her Bachelors of Science degree in Nutrition & Dietetics in 2013 at the University of Nevada, Las Vegas (UNLV). Shortly thereafter, Alexis began her career at Rocky Mountain Health & Wellness where she learned the importance of a “whole person” approach to nutrition care. This passion led to her obtaining high honors in a Masters of Nutrition and Functional Medicine. This enabled her to use Functional Medicine to aid in identifying the root cause of nutrition related conditions in lieu of simply reducing symptoms. She additionally provides a functional medicine based nutrition consulting with specialization in the following: food allergies, autoimmune conditions, digestive disorders, diabetes, fertility, depression, ketogenic and paleo meal planning.

Jenni Terry

Jenni Terry, Health Coach

Jenni is a Functional Medicine Certified Health Coach through The Functional Medicine Coaching Academy and holds a B.S. in Physical and Health Education from Utah State University. A standing theme in Jenni’s life has been her search for health and wellbeing and her passion for helping others. She is grateful to have found both in Functional Medicine! As a patient of FMI herself, with the help of her care team, Jenni was able to heal her body and mind and be free of her debilitating health problems. After this experience, Jenni knew it was her purpose to change her career path and help others uncover the root cause of their ailments and accomplish their own health transformations. Now, Jenni uses her education in functional medicine, functional nutrition, the psychology of eating, mind-body medicine, and positive psychology, as well as her personal experience, to help others make lasting lifestyle changes and reach their optimal health. She coaches others to success by co-creating personalized treatment plans that focus on nutrition, exercise, sleeping habits, stress management, and relationships.