Integrative & Functional Nutrition · New York City
Integrative & Functional Nutritionist in NYC for Gut, Thyroid & Hormone Health
Root-cause, functional-medicine-informed nutrition care for women and men told their labs are “normal” — specializing in gut health, Hashimoto’s, autoimmune disease, and hormones. Serving Manhattan, Brooklyn, Queens, and clients virtually nationwide.
PhD-Trained · Virtual Nationwide · Based in Midtown Manhattan
Take the Root Cause QuizMeet Dr. Sarah Khan, PhD, MBA
I’m an integrative and functional nutritionist based in New York City. My clients usually arrive after years of being told their bloodwork looks fine — while they still feel exhausted, bloated, anxious, or unwell. Working within a functional medicine framework, I help them find and address the root cause rather than chasing one symptom at a time.
My work focuses on the gut, thyroid, hormones, and the gut-brain axis — the systems that quietly drive how you feel every day. Together we use functional lab interpretation, targeted nutrition, and realistic protocols to rebuild your health from the foundation up. Ready to go deeper? Explore my 1:1 functional nutrition programs.
Book a Discovery CallPhD-Level Expertise
Doctorate in Integrative and Functional Nutrition from Saybrook University, with advanced training in functional lab interpretation and systems biology.
A Systems Approach
An MBA and a decade leading enterprise product teams — I bring the same rigor to mapping how your gut, thyroid, hormones, and stress response interact.
Lived Experience
My own autoimmune diagnosis is why this practice exists. I know exactly what “your labs are normal” feels like from the patient’s side.
Conditions I Help Address
Specialized functional nutrition support for the root-cause conditions I see most often in my NYC practice.
Hashimoto’s & Thyroid
Nutrition strategies to calm autoimmune attack on the thyroid and support energy, mood, and metabolism.
Autoimmune Disease
A root-cause approach to autoimmunity — reducing triggers, supporting the gut, and lowering inflammation.
Gut Health & SIBO
Targeted protocols for bloating, IBS, and methane-dominant SIBO/IMO that address the cause, not just symptoms.
Hormones & Perimenopause
Support for cycle changes, perimenopause, and the hormonal shifts driving fatigue, mood, and weight changes.
Chronic Fatigue & HPA Axis
Rebuilding energy by addressing the HPA (stress) axis, blood sugar, and the nutrient gaps behind burnout.
Weight-Loss Resistance
For when diet and exercise aren’t enough — uncovering the thyroid, hormonal, and metabolic blocks.
Functional Nutrition, Integrative Nutrition & Functional Medicine — What’s the Difference?
Functional medicine is a root-cause model of care. Instead of treating each symptom in isolation, it asks why symptoms appeared — mapping how the gut, immune system, thyroid, hormones, and stress physiology interact.
Functional nutrition applies that framework through the most powerful daily lever you have: food. It combines comprehensive intake, functional lab interpretation, targeted supplementation, and personalized nutrition protocols — the hands-on work of actually correcting root causes.
Integrative nutrition widens the lens further, weaving in sleep, stress, movement, and mind-body factors so your plan fits your whole life — not just your lab results.
If you’ve been searching for a functional medicine provider in NYC, an integrative and functional nutritionist is often the practitioner who does the day-to-day root-cause work — in collaboration with your physician. That is exactly how my practice operates: functional-medicine-informed, nutrition-led, and coordinated with your medical team.
Why a root-cause approach changes everything
Most conventional care treats symptoms in isolation — a pill for the thyroid, another for the gut, a third for sleep. Functional nutrition asks why those systems went off track in the first place. By looking at how the gut, thyroid, hormones, and stress response work together, we build one coherent plan instead of a pile of disconnected fixes.
How Working Together Works
A structured, three-phase path from “no one can tell me what’s wrong” to a body you finally understand.
1
Apply & Connect
Start with a short application and a free discovery call. We talk through your story and choose the right level of support together.
2
Investigate
A deep-dive intake plus functional testing where it adds clarity — stool, thyroid, hormones — to map the patterns behind your symptoms.
3
Rebuild
A personalized nutrition, supplement, and lifestyle protocol with ongoing 1:1 support and real-time adjustments as your body responds.
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After years of being told everything was normal, Dr. Khan finally connected the dots. For the first time I understand my body — and I actually feel well again.
Verified Client Review
An Integrative & Functional Nutritionist in NYC — Wherever You Are
My practice is based at 136 Madison Avenue in Midtown Manhattan, and I work with clients throughout Manhattan, Brooklyn, Queens, the Bronx, and Staten Island — as well as virtually with clients nationwide. Every engagement is fully personalized, so whether we meet by video or you’re local to the city, you get the same root-cause depth of care.
Frequently Asked Questions
Do I need to live in New York to work with you?
No. Care is virtual, so you can work with me from anywhere in the US. Most of my clients are in New York and the surrounding area, but location does not affect the depth of the work.
Do you accept insurance, HSA, or FSA?
No, I do not accept insurance, HSA, or FSA. Working privately lets me give the personalized, concierge-level attention this work requires, without the limits insurance places on time and approach.
What does the concierge support actually include?
Between our 1:1 sessions, you have 24/7 access to me for questions and real-time adjustments. When something comes up, you are not waiting weeks for an answer, which matters most when symptoms shift unexpectedly.
Which program should I choose?
That is what the application helps us decide. The programs differ in length and how often we meet, from bi-weekly to monthly 1:1 support, so we match the level of support to where you are and what you need.
Do you only work with women?
No. I work with both men and women, though more women find their way to my practice. The common thread is the type of concern and mindset, not gender.
What is functional nutrition, and how is it different from seeing a regular dietitian?
Functional nutrition looks for the root cause of your symptoms rather than managing them one at a time. Instead of asking only what you should eat, I ask why your body is responding the way it is, what is happening with your gut, your thyroid, your hormones, and your stress physiology, and build a plan around your biology rather than a generic template.
Are you a functional medicine doctor?
No — I am a PhD-trained integrative and functional nutritionist, not a physician. I work within the functional medicine framework and often collaborate with functional and conventional medicine providers. I do not diagnose disease or manage medications; I lead the nutrition, lifestyle, and functional-testing side of root-cause care.
What conditions do you specialize in?
My practice centers on the root-cause concerns I see most often: Hashimoto's and thyroid issues, autoimmune disease, gut health including IBS and methane-dominant SIBO, hormonal and perimenopausal changes, chronic fatigue and HPA-axis dysfunction, and weight-loss resistance. The common thread is people who have been told their labs are normal but still do not feel well.
Do you do lab testing or functional testing?
Yes, when it adds clarity. Depending on your situation, that may include functional stool testing, comprehensive thyroid panels, hormone testing, and a closer look at the standard bloodwork you already have. I use testing to confirm what your symptoms are pointing to and to make your plan more precise, never just to order for its own sake.
Will you work alongside my doctor?
Absolutely. Functional nutrition is meant to complement your medical care, not replace it. I do not diagnose disease or change your medications, that stays with your physician. What I add is the nutrition and lifestyle layer most conventional visits do not have time for, and I am glad to coordinate so everyone is working toward the same goal.
How long until I see results?
Most clients notice early shifts, better energy, less bloating, steadier mood, within the first few weeks. Deeper change, like calming an autoimmune flare or rebalancing hormones, usually unfolds over a few months as we work through the root causes in order. Healing is rarely linear, which is one reason the programs are built around ongoing support rather than a single visit.
Do you recommend supplements, and do I have to buy them from you?
When supplements will genuinely help, I recommend specific, high-quality ones through my professional dispensary so you know exactly what to take and at what dose. There is never any pressure to buy them through me, and supplements are always part of a bigger plan, supporting the food, lifestyle, and root-cause work rather than standing in for it.
How do I get started?
The first step is a discovery call. It is where we talk through what you have been experiencing, decide whether we are a good fit, and choose the right level of support together. If you are not sure where your symptoms are coming from yet, you can also take my free Root Cause Quick Scan first, a low-pressure way to begin.
Not sure where your symptoms are coming from?
Take the free Root Cause Quick Scan and get a clearer picture of what might be driving how you feel — in just a few minutes.
