MCAS, POTS & Histamine Intolerance: Hidden Drivers of Chronic Symptoms | Michelle Shapiro, RD

Mysterious symptoms. Confusing diagnoses. Years of being dismissed.

In this episode, Michelle Shapiro joins me to unpack the often misunderstood and overlooked world of mast cell activation syndrome (MCAS), histamine intolerance, postural orthostatic tachycardia syndrome (POTS), and hypermobility conditions.

Drawing from her own health journey and experience with thousands of clients, Michelle unpacks why conventional medicine often overlooks these complex, overlapping conditions—and how a root-cause, systems-based approach can lead to real healing. From nervous system regulation to low-histamine nutrition, this episode is a must-listen for anyone struggling with unexplained chronic symptoms.

You’ll learn:

• What MCAS is and why so many people are misdiagnosed
• The link between MCAS, POTS, and connective tissue disorders
• How nervous system regulation impacts immune reactivity
• Which foods trigger histamine flares and how to build a low histamine diet
• The surprising connection between hormones and histamine
• Why building muscle is critical for recovery from MCAS, POTS, and hypermobility

Whether you’re a clinician or someone living with these symptoms, this conversation offers insight, hope, and a roadmap forward.

Who is Michelle Shapiro?

Michelle Shapiro, RD is a functional/ integrative Registered Dietitian who has helped over 3,000 clients transform their health over the past 11 years. As the founder of an NYC-based virtual private practice, Michelle leads a team of six expert nutritionists who specialize in complex cases including histamine issues, gut dysfunction, chronic anxiety, and weight concerns. She is the creator of the viral Histamine Essentials Webinar, which is available now on replay, and the host of the top-rated podcast Quiet the Diet, where she breaks down the science behind chronic illness in a way that actually makes sense and makes you feel seen. Michelle is the go-to expert for people who have tried everything and are ready for a real plan.

This episode is brought to you by:

• OneSkin - Get 15% off with the code DRLYON – https://www.oneskin.co
• Ned - Get 15% off with code DRLYON – https://helloned.com/DRLYON
• Beef.org – Your go-to resource – https://BeefItsWhatsForDinner.com
• LMNT - Get your free LMNT Sample Pack with any purchase – https://DrinkLMNT.com/DRLYON

Find Michelle Shapiro at:

• Instagram - https://www.instagram.com/michelleshapirord
• Histamine Webinar Replay - https://michelleshapirord.com/histamine-webinar
• Apply to work with Michelle’s team: https://airtable.com/appzFCkAqbbL4J2Qu/pagw0ynsqYbBzMjes/form

Find Me At:

• Instagram:@drgabriellelyon
• TikTok: @drgabriellelyon
• Facebook: facebook.com/doctorgabriellelyon
• YouTube: youtube.com/@DrGabrielleLyon
• X (Twitter): x.com/drgabriellelyon
• Apply to become a patient – https://drgabriellelyon.com/new-patient-inquiry/
• Join my weekly newsletter – https://institute-for-muscle-centric-medicine.ck.page
• Get my book – https://drgabriellelyon.com/forever-strong/

Timestamps:

00:00 – Introduction: Dismissed symptoms and hidden syndromes

01:43 – What is mast cell activation syndrome (MCAS)?

03:33 – Why histamine is the “loudest” chemical messenger

06:39 – MCAS symptoms: from flushing to anxiety

08:22 – Root causes: mold, toxins, and the “bucket” theory

11:15 – Diagnosing MCAS: blood, urine, and biopsy challenges

15:11 – Food patterns: how "healthy" foods trigger MCAS

16:53 – MCAS vs histamine intolerance: what’s the difference?

25:06 – High-histamine foods: what to avoid (and why)

27:37 – Nervous system & immune system: the feedback...