Functional Nutrition & GI Mapping at Amity Health DPC

Root-Cause Nutrition Care in Costa Mesa & Orange County

At Amity Health DPC, Functional Nutrition is fully integrated into our Direct Primary Care model. Rather than offering nutrition as a standalone service, we combine personalized, evidence-based nutrition care with ongoing access to a physician—ensuring your plan is medically sound, coordinated, and focused on long-term results.

Functional Nutrition services are led by Cristina Terwilliger and delivered in conjunction with an Amity Health DPC membership, giving you comprehensive primary care alongside advanced nutrition guidance.

Meet Cristina Terwilliger

What Is Functional Nutrition?

Functional Nutrition looks at how food, digestion, and lifestyle interact with your unique physiology. Instead of managing symptoms alone, this approach focuses on identifying underlying imbalances such as gut dysfunction, nutrient deficiencies, inflammation, and hormonal disruption.

Using detailed intake assessments and advanced lab testing, we build targeted plans that support healing at the source.

Functional Nutrition Services

GI-MAP and Functional Lab Testing

Advanced stool testing provides insight into the gut microbiome, digestive enzymes, inflammation markers, and hidden infections. This allows nutrition recommendations to be data-driven rather than guesswork.

Personalized Nutrition Planning

Nutrition plans are tailored to your individual needs and may focus on improving digestion, reducing inflammation, stabilizing blood sugar, and supporting hormone and immune health.

Root-Cause Protocols

Care may include structured protocols for leaky gut repair, autoimmune support, hormone and thyroid balance, metabolic health, detoxification, and stress or adrenal recovery. All recommendations are aligned with your medical care.

How the Membership Works

Functional Nutrition services are offered exclusively alongside an Amity Health Direct Primary Care membership. This integrated model ensures collaboration between your nutritionist and physician throughout your care.

Your membership includes full access to Amity Health DPC benefits, including unlimited primary care visits, direct physician messaging, extended appointment times, and discounted labs and imaging.

In addition, you receive ongoing Functional Nutrition care with Cristina, including lab review, personalized nutrition and supplement guidance, and continued support and accountability.

An Amity Health physician remains involved to review labs, provide medical context, and ensure all recommendations align with your overall health plan.

Why Choose an Integrated DPC + Functional Nutrition Model?

Many patients seeking functional nutrition have experienced fragmented care, with nutrition, labs, and medical oversight handled separately. At Amity Health DPC, everything is coordinated through a single care team.

This model allows for more thorough evaluation, safer and more effective protocols, and a clearer path toward long-term health improvement.

Who This Is For

This approach is well suited for individuals dealing with chronic digestive symptoms, fatigue, hormone or thyroid issues, autoimmune or inflammatory conditions, food sensitivities, or persistent symptoms despite normal standard labs.

If you are looking for nutrition guidance supported by medical expertise and ongoing primary care, this integrated model was designed for you.

Get Started

Functional Nutrition at Amity Health DPC combines personalized nutrition care with direct physician access to support meaningful, lasting health changes.

Schedule a consultation to learn whether Functional Nutrition with Cristina Terwilliger is right for you and how to enroll in the combined DPC and Functional Nutrition membership.

Cristina Terwilliger is a Functional Nutritionist specializing in gut health, metabolic dysfunction, inflammation, and chronic symptom resolution. She works closely with Amity Health physicians to identify root causes of disease and create individualized nutrition and lifestyle plans tailored to your labs, history, and goals.

Her approach emphasizes food as medicine, functional testing, and sustainable strategies designed to support lasting health—not short-term fixes.