It’s personal

Just what is functional medicine and why do some DOs gravitate to it?

Learn more about this growing practice of personalized medicine, often described as ‘root cause medicine.’


Aunna Herbst, DO, was in her early 30s when she decided to go to medical school. The former lifestyle and health coach had gotten into nutrition for personal reasons. But when her business became so successful that it grew too big, she decided to sell it.

Her love of biochemistry coupled with her natural affinity for healing led her to Oklahoma State University College of Osteopathic Medicine (OSU-COM).

“During residency training, I wondered how I was going to incorporate the two worlds of osteopathic medicine and nutrition,” says Dr. Herbst. “I pursued functional medicine as a means to bridge them.”

Dr. Herbst’s functional medicine pursuit was very successful and led to a gig helping the Cleveland Clinic get their fledgling Center for Functional Medicine started. Many of the holistic qualities of functional medicine align with those of osteopathic medicine, she notes.

What exactly is functional medicine?

If you’ve wondered about the specifics of functional medicine, you’re not alone.

According to the Institute for Functional Medicine (IFM), which is considered the gold standard of training in the field, “the functional medicine model is an individualized, patient-centered, science-based approach that empowers patients and practitioners to work together to address the underlying causes of disease and promote optimal wellness.”

Functional medicine practitioners incorporate modalities such as nutrigenomics, which looks at an individual’s interaction between nutrients and their genes, pathophysiology and biochemistry to optimize function, says Dr. Herbst.

“Functional medicine is what A.T. Still must have envisioned osteopathic medicine to be,” she says. “It’s a truly holistic approach.”

After training at IFM, Dr. Herbst  set up practice in Grove, Oklahoma, and “natural medicine seekers began coming out of the closet” as her practice grew exponentially.

She became so well-regarded in the field that when the Cleveland Clinic decided to delve into the world of functional medicine, they invited Dr. Herbst to join them. Dr. Herbst helped the Cleveland Clinic develop and expand the Cleveland Clinic’s Center for Functional Medicine (CCCFM). She became the center’s second full-time physician in 2015 before becoming its operations director for a year. She has recently returned to private practice back home in Oklahoma.

Mark Hyman, MD, one of the pioneers in the field of functional medicine, explains in this video the difference between conventional medicine and functional medicine.

For Christine Maren, DO, functional medicine filled a void, both professionally and personally. Growing up in Boulder, Colorado, she had what she describes as a “holistically minded upbringing,” which is why she gravitated toward osteopathic medical school.

When she wasn’t getting answers to her own health problems through a conventional medical model, she went down the path of functional medicine as a patient first before becoming a practitioner.

“Functional medicine is a very individualized and personalized approach to medicine with a focus on root cause rather than symptomology,” says Dr. Maren. “I always think it should be called ‘root cause medicine.’ ”

FM takes time, engagement

While conventional medicine does a great job at treating acute and emergency medical situations, functional medicine is better suited toward chronic illness, says Dr. Maren.

“Most of my patients have seen conventional doctors and didn’t get effective treatment. They need someone to dig deeper and do a lot of investigative work,” she says.

At CCCFM, Dr. Herbst estimates that over 60 percent of the patients had a chronic illness and had exhausted all other treatment options. “They’d often come in with reams of medical records. They’d been to the likes of a Mayo Clinic and nobody could help them.”

Athletes, often professional, comprise another large group of patients at CCCFM, led there by a desire to optimize their health and prevent disease. “Mom and dad have dementia, and I don’t want it,” is typical of that group, says Dr. Herbst.

A third group of patients were not sure why they came there and were hoping for a quick fix. “Functional medicine is not a quick fix,” says Dr. Herbst. “It’s a process. It takes work and an active patient, or it won’t be successful.”

The rise of FM

Functional medicine is still a relatively fledgling field that is beginning to see explosive growth. The CCCFM, which opened in 2014, quickly outgrew its space and has since expanded into a prime 10,000-square-foot facility with more satellite locations being added, says Dr. Herbst.

Despite its popularity, functional medicine is often criticized for its use of clinical evidence rather than research-based evidence.

“At first, the Center was considered the two-headed stepchild for specialists at Cleveland Clinic,” says Dr. Herbst. “But the more grand rounds we made and the more progress we made with patients, the more they came around.”

A series of studies which include functional medicine approaches to asthma treatment, Type 2 diabetes and prostate cancer are currently underway at CCCFM.

“Our goal at CCCFM was to put functional medicine’s name out there,” says Dr. Herbst. “And really the only way to do that is through studies.”

A new model

Part of the allure of functional medicine, and why academic hospital-based centers like Cleveland Clinic are embracing it, is motivated in part by the shift in medical reimbursements toward outcomes instead of volume, according to an interview in Holistic Primary Care with Mark Hyman, MD, who along with Patrick Hanaway, MD, was instrumental in starting Cleveland Clinic’s CFM.

A report on outcomes of more than 4,200 patients treated at CCCFM found that CCCFM patients had greater clinical improvements and lower health care costs than patients receiving conventional care at Cleveland Clinic.

Part of the success of functional medicine is grounded in what might be considered an osteopathic approach to care: partnering with your patient and believing in the body’s innate ability to heal.

“What I loved about my DO training is the underlying philosophy that the body has an ability to heal itself,” says Dr. Maren.

In functional medicine, Dr. Maren says, “I found an entire tribe of people who were asking the same questions I was asking, which is why. And functional medicine helps me find answers to that for myself and also for my patients.”


  1. Paul Schmidt, DO

    “the functional medicine model is an individualized, patient-centered, science-based approach that empowers patients and practitioners to work together to address the underlying causes of disease and promote optimal wellness.” It’s offensive to us other physicians to imply we don’t do this. Functional medicine physicians in my geographic area use non-FDA approved devices to diagnose things through the skin. They do dangerous IV vitamin infusions, and order tests and treat based off of the test results without seeming to understand what the test indicates such as reverse T3 that is normal but near the limit of normal with all other thyroid tests in normal range. Functional medicine doesn’t seem to be as science based as is claimed.

    1. carolyn owens

      I am not a dr, but as the patient I expect a dr who is going to take care of me with an individualized approach and not just push drugs in a 7min consult. Essentially, I don’t care what type of medicine is practiced but take care of the patient with care and diligence. Most drs don’t even listen to the patient. We, the patients have to be our own health advocates and we appreciate physicians that listen.

    2. davea0511

      A more fundamental difference is that conventional medicine treatments usually focus on restricting some process in the body … usually exhibiting an unpleasant symptom for the patient, whereas functional medicine tries to not restrict those processes but instead improve the function of an organ or system that will naturally result in an alleviation of the symptom. You can say all you want that conventional medicine does the later, but if you really think about most of the conventional treatments you must admit that restricting a negative symptom is the primary focus. Whether you agree that Functional Medicine is effective is irrelevant to that fact.

    1. Achina Stein

      If you go to the Institute for Functional Medicine, there is a program that you may enroll in.

  2. Jim D Notimpressed DO

    As a physician with a back ground in biochemistry, I would be forceful to reject the tenants of functional medicine. This is not evidence based nor scientifically accurate. This makes DOs look like naturopaths. Quack, quack, quack.

    1. davea0511

      Naturopaths would strongly disagree with you. Naturopaths identify themselves as getting the body to heal itself independent of any kind of substance, be it natural or synthetic, whereas FM doctors use medicine, both pharmaceutical and non-pharmaceutical. I am curious about which “tenants” of functional medicine you thing is not evidence based nor scientifically accurate, since their only real tenet is to resolve root problems more than symptoms.

  3. Alexander Thermos

    As a DO that experienced extensive clinical results while practicing first as a Chiropractor prior to Medical School, I knew that Holistic approaches ‘worked’. As time has passed – and with the development of many terrific laboratories (Genova Diagnotics, Metametrics, IgenX, Doctors Data, DiagnosTechs, Great Plains Laboratory, etc etc) Functional Medicine has a plethora of tools for us to evaluate our Patients with and determine functional losses and abnormal pathways and toxicities. I laugh when a conventional Doc scoffs at a diagnosis, as more often than not – I have more Laboratory evidence to support my approach than the ‘hunch’ they are operating upon.

    Functional Medicine is indeed a science based approach to Patient evaluation and treatment, and offers clues that have been missed / skipped over by traditional approaches and the dis / mis-information campaign employed by big pharma.

    I have been using Functional Medicine approaches since my days as a Chiropractor, while using Great Smokies Diagnostic Laboratory.

    There are numerous Chiropractors that have made their practice as Functional practitioners, a role better suited to a DO – and the Naturopathic Physicians are indeed capitalizing on this. If Osteopathy is to survive, embracing a more Holistic approach will be necessary – or the public will continue to aquire the viewpoint that a DO and an MD are essentially the same.

  4. Lawrence Uhrig, D.O.

    Something I don’t understand is why Osteopathic physicians and the Osteopathic Profession as a whole continue to try to “reinvent” themselves as something special and different when we could just follow the true principles of traditional Osteopathy and provide Osteopathic Manipulation treatment as an effective adjunct to regular medical care. I have practiced such for 30 years and find so many patients being ignored for regular and common ailments that could be, in part or totally, treated with the traditional Osteopathic approach.

    We don’t need new procedures and newly named or renamed techniques- we have everything we need. It just takes time to teach it and use it the way Dr. Still and early Osteopathic physicians used it.

    It’s not rocket science or “Functional Medicine”- it’s Osteopathy.

    1. D. D.

      I love this and I applaud you for saying this! Thank you! The current structure of the osteopathic profession, as well as the future path that osteopathic profession is heading towards are both “MD-wanna-be”. We should celebrate and encourage our distinctiveness and the unique training we are already provided. DOs are already functional and holistic medicine if they stick to osteopathic tenants.

    2. Anette Mnabhi

      Well said-if one practices medicine applying the FULL tools and philosophy of Osteopathic Medicine, you are seeking the root cause of illness, correcting the underlying issues and helping your patient heal!!

  5. Joe Morgan DO, JD, ABIHM

    As a former ophthalmologist who retrained for 3 years as a preceptor to become certified in Integrated Holistic Medicine, I am amused at the mostly uninformed comments of my colleagues. Holistic or Functional or Integrated Medicine is the application of diet, nutrition, herbs, oils, physical medicine and whatever else it takes to normalize the physiologic and biochemical functions of the body. There are tons and tons of research to support Functional medicine but it you don’t look for it you of course don’t know it is there.
    All my patients have a detailed Nutritional Assessment Questionnaire first. Their symptoms will target which organ[s] is not functioning best. Its all about regaining normal physiologic function by natural methods and not chemicals. Also Functional and Holistic Medicine are much better than traditional at managing chronic disease- we will always need acute care and surgical care. If you think traditional medicine is addressing obesity- you are wrong. All doctors should be trained to start some type of obesity treatment but even the PCPs ignore it for the most part. And, to ignore any healing modality even if it is ancient Chinese medicine, is not fully treating the patient. Mainstream medicine with which we include ourselves so we are equal to our MD colleagues is getting too dangerous- many drugs have side effects of cancer or death. Who needs that formulary. Keep an open mind and keep Osteopathy Holistic as promoted for long time but not practiced

    1. Joe Morgan, DO JD ABIHM

      Training is self study through structured programs of various organizations. Most will lead to a certification exam. These are not give away exams, I failed first time on mine.
      The A4M has such a program but it it the most costly of the lot. The ABoIM has a fellowship online but is costly- then take the exam. Functional Medicine Institute used to and may still have a study program.
      In addition you need to spend some time in an actual clinic working with some qualified doctor to see their approach to patients.
      As doctors we talk about lifelong learning and retraining like this is part of lifelong learning.
      Every doctor should take the blood chemistry analysis from Dicken Weatherby, ND. He is expert in blood work analysis and how it relates back to disease, and most importantly, what the optimal values are instead of relying on the lab reference range which is pretty worthless. Yesterday I saw a patient lab from another clinic when patient brought it in. His TSH was 4.3, and not on any meds yet. Optimal is about 1.8 to 2.6. Keep studying and learning.

  6. Daniel Kinsey

    My main gripe with functional medicine is the cost-worth. From what I understand, functional medicine is pretty much a “order as many tests as possible” approach, and yeah this approach might work for very specific populations (e.g. athletes, patients with very distinctive genetic metabolic issues) but not for the majority of the population. Most people can follow conventional dietary and exercise advice that has been around for years and see amazing results. It’s misleading to push patients towards functional medicine when they don’t really need it; this approach also costs the system way more money because of how many tests are ordered and associated one-on-one patient interactions with physicians. General dietary advice can be given by a health coach, brochure, or even personal trainer, all of which are much cheaper options.

    As a first year DO student, I also don’t like the associations that people are making, clumping and defining DOs as being more holistic than MDs or other providers. I don’t plan on practicing individualized functional medicine because it’s not cost effective. Yeah, I will individualize treatment based on osteopathic examinations, but osteopathy and functional medicine are not and should not be synonymous. The more the DO profession associates with arguably unsupported and pseudoscience the less credibility we hold. It’s the same argument that I’d make for forcibly learning ill-supported osteopathic manipulations.

    1. Joe Morgan

      Daniel, I appreciate your posting and comment. It seems that you don’t know what you don’t know yet.
      Individualized functional medicine or holistic medicine is extremely effective. Would you rather be half cured for regular price or cured and well for a little more.
      Holistic may mean the body as a whole as the osteopathic concept describes, but, there is another definition that holistic includes using all the modalities needed and available.
      Western medicine denies the existence of an electromagnetic field around the body but we put pads on and get our EKG from the skin.
      As you master the present Traditional Mainstream medicine of the USA you will find that Ayurvedic and Chinese medicine have been around for about 5000 years, and have healed masses of people. Many surgical instruments used today have a design based in Ayurvedic medicine which included surgery even in ancient times.
      Don’t forget Biblical Frankincense- a tremendous antimicrobial, anti-inflammatory, analgesic herbal remedy that still works as well to day as many present day drugs with less toxicity and much less cost.
      Good luck in hour journey to becoming a masterful physician-knowing people and healing equally for best results.

    2. Anette Mnabhi

      It is sad to see your final statement on be interraced to learn ill-supported manual treatments-why go to an OSTEOPATHIC SCHOOL? We help people every day who suffer from acute and chronic pain-from my student days through resident I treated hands on every day. with the opined crisis and so many people in pain hands on skllls are needed more than ever.

      The physical therapy profession is slowly working on research, bit if you do a good search – there is practically no research to support the majority of treatments and modalities used. IN Medicine most surgeries have no search to support their use-finally some are looking and-saying oh, we can treat some appendicitis without surgery and they do fine.
      Very little of what we do in medicine is suited to a double blind Medicine-including manual treatments, there is a growing body of research on OMT. Take some time to look up the work on the Cranial Rhythmic Impulse by Glonek and Nelson.

  7. RayR

    When a patient has an ANA >2560 and other immune complex irregularities along with small fiber neuropathy with other neurological symptoms and a conventional neurologist doctor at MGH stating in a letter that the patients neuropathy is not immune mediated, it’s time to question such arrogance.

    A 25 minute meeting with a conventional doctor along with cursory blood tests to support his/her assumptions with a Healthgrade rating of 1-5 stars offers no relief to those chronically ill.

    Chronically ill patients seek relief from symptoms not from egos.

  8. Achina Stein DO

    I am proud to be an osteopathic physician, but conventional medicine failed my son. Functional medicine saved his life. Yes there are people who do functional medicine dangerously just like conventional medicine is done dangerously. Both should lose their licenses.
    If I didn’t learn about functional medicine, I know in my heart, my son would not have gotten well or worse would be dead. After practicing conventional medicine as a psychiatrist for 22 years, in my journey to get my son’s health, I knew I couldn’t unlearn what I learned in the process and go back to the way I was treating my patients. I became a certified practitioner in functional medicine and have been practicing functional medicine since 2012. Once you know the power of functional medicine to heal, you can’t turn back. So many of my patients are thankful for the work we’ve done together. And we are talking about serious issues like IBS, CFS, CPS, autoimmune d/o, refractory depression, debilitating panic disorder in people who can’t function and at risk of losing their jobs or dropping out of school. I have had several 4th year med students from UNECOM do a rotation with me. I have had physicians, PAs, nurses, and NPs shadow me for free for a day, a month, a semester as my way of paying it forward. So if you are interested in opening your eyes to the way medicine really should be practiced, have an open mind and truly want to learn, contact me. I will show you how its done for real. Peace APS

    1. Suleyman Yildiz

      Hi my name is Suleyman Yildiz was diognosed with Parkinson’s about a year and half ago not taking any medication don’t need it yet but I have been reading about the funcional medicine I am all for it I live in Yonkers ny can you please give me names of functional medicine doctors in my area please you can call me or text me please will be greatly appreciated 917 8381882 I am 64 years old but healthy other than having Parkinson’s thank you very much

  9. Goedon Laird DO

    I have practiced osteopathic medicine for 51 yrs and am certified in both general surgery and family medicine. When I started practice omt and osteopathic practice were discouraged as quackery and we were not accepted in the medical community as equals. I believe that if the medicine you practice does no harm and the patient gets good results it should be acceptable. Medicine practiced in other parts of the world should be considered if results are good. There are many educational opportunities for learning that are not taught in medical school .And are discouraged by Big Med because of financial considerations. Look at the history of your profession when making decisions ATStill teachings are still true today

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