We use the term “functional nutrition” a lot around here, so you might be wondering what it’s all about.

Maybe you’ve heard it used by dietitians, but you have absolutely no idea what it means.

Or maybe you ARE a dietitian, and you’ve heard about functional nutrition, but you don’t fully understand how to implement it.

If so, then keep reading!

We’ll define functional nutrition, explain the philosophies behind it, and provide examples of how a dietitian might use it in practice.

Want to save this article? Click here to get a PDF copy delivered to your inbox.


Overview of Functional Nutrition

The term “functional nutrition” is actually a component of a concept known as “functional medicine.”

Functional medicine is a model or framework that some doctors use to address the root cause of disease.

Before we can truly understand functional nutrition, we’ll have to take a closer look at functional medicine.

What Is Functional Medicine?

The concept of functional medicine was created by a biochemist named Jeffrey Bland in 1990 (1).

Bland was familiar with integrative medicine, a kind of healthcare that focuses on the patient as a whole person (mind, spirit, body) and uses both conventional and alternative treatments (2).

But being a biochemist, he saw the value of molecular medicine, which seeks to understand and treat disease based on the causes and mechanisms at a molecular level (3, 4).

So, he decided to combine integrative medicine with molecular medicine to form a framework called “functional medicine” (5).

In 1991, the Institute for Functional Medicine (IFM) was founded as a way to promote functional medicine and provide education to healthcare practitioners.

In a nutshell, functional medicine is a model that allows patients and practitioners to work together to address the underlying causes of disease by evaluating biological systems (6).

Functional medicine may look a little different depending on who’s using it, but in general, it can be summed up by these characteristics:

Characteristics of Functional Medicine

1. It is patient-centered rather than disease-centered, with the goal of promoting health that extends beyond the absence of disease (7).

2. The practitioner evaluates clinical imbalances within biological systems and identifies points of connection that reveal the underlying cause of disease or dysfunction (5, 8).

3. The aim is to treat the root cause of disease to promote healing, instead of treating symptoms to provide temporary relief (6).

4. Lifestyle changes are heavily emphasized in the prevention and treatment of chronic diseases (7).

5. Through a therapeutic partnership, the practitioner and the patient work together to achieve goals (6).

How Functional Medicine Differs from Conventional Medicine

In practice, the functional medicine approach looks very different from conventional medicine.

For example, let’s say a patient presents with eczema, an inflammatory condition characterized by itchy, scaly skin.

If this patient sees a doctor who practices conventional medicine, they’ll most likely be prescribed several drugs and ointments that suppress the immune system and lower inflammation in order to relieve symptoms (9, 10).

But a functional medicine doctor will ask the question, “WHY is the immune system reacting this way?”

Maybe they have food allergies, sensitivities, imbalanced gut bacteria, or high stress levels that are triggering their eczema (11, 12, 13).

So their treatment will include further investigation into possible root causes, plus diet and lifestyle interventions to address them.

The real difference is that the functional approach aims to provide true healing from the bottom up, while the conventional approach to many chronic illnesses is often like a band-aid.

In acute care (emergency situations), conventional medicine works beautifully, using drugs and surgery to save lives.

But when it comes to chronic diseases, which are often diet and lifestyle-related, many drugs only MASK symptoms, leaving the root causes unresolved.

Doctors who practice functional medicine believe it is a better model for addressing chronic disease, because of its focus on prevention through lifestyle changes such as diet, exercise, and stress management.

Because nutrition plays such an important role in functional medicine, doctors often refer patients to dietitians and nutritionists who practice functional nutrition.

What Is Functional Nutrition?

The IFM defines functional nutrition as an approach that “emphasizes the importance of high-quality foods and phytonutrient diversity to address clinical imbalances and move people to the highest expression of health” (14).

My dietitian friends may be thinking, “Well, that doesn’t sound any different than what I learned in school!”

In some ways, you’re absolutely right.

Just like traditional dietetics, functional nutrition also uses the nutrition care process and personalized dietary interventions to improve health (7).

The main difference is that functional nutrition requires dietitians to take a closer look at the patient as a whole person (mind, body, spirit) and base nutrition and lifestyle recommendations on the underlying causes of disease or dysfunction.

For example, let’s say you’re evaluating a patient who has been diagnosed with diarrhea-prominent irritable bowel syndrome (IBS-D).

The non-functional approach might include advising the patient on the low-FODMAP diet, how to identify and avoid trigger foods, and nutrition education to prevent diarrhea-related dehydration.

A functional approach, on the other hand, would involve functional testing for underlying causes, like SIBO, gut dysbiosis, parasites, food sensitivities, allergies, or intolerances and a thorough evaluation of lifestyle and health history (15, 16). The root causes would then guide the interventions.

Because this approach requires in-depth knowledge and critical thinking skills, many dietitians who want to practice functional nutrition find it helpful to obtain additional certifications or training.


Using Functional Nutrition in Practice

The concept of functional nutrition isn’t too difficult to understand, but if you’re a dietitian you may be wondering how to actually APPLY it to your practice.

Thankfully, there are tools to help guide you as you begin to implement the functional nutrition framework.

Two of the most widely used are the functional medicine matrix and the 5-R protocol. Let’s explore these below!

1. The Functional Medicine Matrix

Functional medicine practitioners use tools to organize information, analyze that information, and guide treatment decisions while still allowing for flexibility and personalized care.

They prefer using systems and models that allow them to focus on a patient’s unique clinical picture, rather than “cookie cutter” formulas or templates.

And that’s where the functional medicine matrix comes in!

Basically, the matrix is a reminder to put on your detective hat and consider ALL of the patient’s potential causes of dysfunction so that you can prescribe nutrition interventions that address these root causes. 

It was designed to be used by doctors, but it works for dietitians and nutritionists as well.

The actual functional medicine matrix is copyrighted by IFM, so we are not including the image in this article, but will summarize the main points below. You can find a digital copy of the matrix here. 

Section 1: The 7 Core Imbalances

The functional medicine matrix contains a box in the center that prompts the practitioner to organize the patient’s clinical presentation based on what the IFM considers to be the “seven potential core imbalances” that may underlie any disease state (17).

These include:

  • Assimilation includes digestion, absorption, respiration, and the gut microbiome.
  • Defense & repair refers to immunity, inflammation, and infection.
  • Energy deals with energy regulation and mitochondrial function.
  • Biotransformation & elimination involves toxicity and detoxification.
  • Transport describes the cardiovascular and lymphatic systems.
  • Communication is comprised of neurotransmitters, endocrine, and immune messengers.
  • Structural integrity encompasses everything from subcellular membranes to musculoskeletal structure.

Section 2: The Patient’s Story

The column on the left side of the matrix (“retelling the patient’s story”) is a way to organize the patient’s disease pathogenesis into “antecedents, triggers, and mediators” (18).

  • Antecedents are any factors that predispose the patient to illness. These could be genetic or environmental (nutrition, physical fitness, etc.).
  • Triggers are any factors that provoke the signs and symptoms of illness. Some examples are infection, trauma, environmental toxins, or foods that the patient is allergic or sensitive to.
  • Mediators are any factors that contribute to pathological changes and dysfunctional responses. These mediators can include biochemical factors like cytokines and hormones, or they might be psychosocial factors, like the patient’s thoughts and beliefs.

Section 3: Lifestyle Factors

Finally, the bottom row organizes the patient’s modifiable lifestyle factors into five categories: sleep & relaxation, exercise & movement, nutrition, stress, and relationships.

Functional nutrition practitioners are equipped to address all of these lifestyle factors to some degree, but their area of special expertise and focus is nutrition.

2. The 5-R Protocol

Many functional dietitians and nutritionists also use a modified version of the IFM’s “5-R protocol” to address gastrointestinal issues in patients with chronic conditions:

The 5-R protocol is as follows:

1. Remove: Remove any foods from the diet that you are allergic, sensitive, or intolerant to, as well as any pathogens in the digestive tract.

2. Replace: Replace anything you are deficient in, such as vitamins, minerals, fatty acids, digestive enzymes, bile, etc.

3. Repopulate: Repopulate your gut with the right balance of gut bacteria, as needed, using probiotics & fermented foods.

4. Repair: Repair damage to the gut as needed, with supplements to support the process.

5. Rebalance: Examine your current lifestyle & look for places in which it is unbalanced. Things to examine include sleep quality, stress levels, work-life balance, social support, and stress-relieving activities.

The 5-R protocol is a helpful tool because it provides a framework for addressing complex issues that require multiple nutrition interventions.

The steps can be done in order or as a simultaneous multi-pronged approach.


Additional Resources

If you’re reading this and thinking, “Wow, all of this sounds great! Where can I learn more?”, then these resources are for you:

1. The Functional Nutrition Library

Interested in learning more about functional nutrition on your own time and at an affordable price point?

Then you’ll love the Functional Nutrition Library!

It’s our membership site for dietitians and other wellness professionals to use as an educational/reference tool in their practices.

It includes functional nutrition recommendations for a variety of conditions, plus information on special diets and supplements, tips for lab interpretation, and more!

The notes are updated weekly in order to make the content more comprehensive and helpful for you. It’s really the perfect online reference for functional dietitians!

2. Integrative & Functional Nutrition Academy

If you’re ready to take your knowledge game to the next level, then you MUST check out the Integrative & Functional Nutrition Academy.

It is an online training and credentialing program offered by dietitians Kathie Swift and Sheila Dean.

Enroll in your choice of online training courses to complete at your own pace. Do them all, and you’re eligible for the IFNCP credential, which is recognized by CDR!

PS – IFNA also offers a FREE listserv that is open to ALL dietitians (even if you are not an IFNA student) 🙂 Just email info@ifnacademy.com to request an invite.

Already an IFNA student or alumnus? Email us at erica@functionalnutritionlibrary.com for an exclusive 50% discount to The Functional Nutrition Library.

3. Dietitians in Integrative and Functional Medicine

If you’re a registered dietitian in the US, you may be familiar with the Dietitians in Integrative and Functional Medicine (DIFM) dietetic practice group within the Academy of Nutrition and Dietetics.

DIFM provides continuing education, newsletters, webinars, and a free subscription to the Natural Medicines Comprehensive Database for its members.

This is an excellent resource for any dietitian who is part of AND and interested in practicing functional nutrition.


Final Thoughts

At its core, functional nutrition is a philosophy that promotes the use of food as medicine to prevent and alleviate diet and lifestyle-related disease.

By addressing the root cause of disease or dysfunction, functional nutrition practitioners are able to promote healing instead of simply masking symptoms.

If you are a patient looking for a dietitian who practices functional nutrition, you can search for one here or here.

If you are a dietitian who wants to learn more about functional nutrition training and resources, consider joining our Functional Nutrition Library!

Want to save this article? Click here to get a PDF copy delivered to your inbox.

Join the FNL

What Is Functional Nutrition?