For Jamie Frees Miller, each new phase of life seemed to bring a new health challenge.

As a baby, it was recurring strep throat. In childhood, constipation. In puberty, painful periods and severe acne.

But starting college came with a whole new batch of symptoms that affected her academic and social life.

“All through college, it was brain fog, horrible anxiety, nausea, acid reflux—I couldn’t eat without taking Tums,” she says. “And the fatigue was so bad that the woman at the dining hall would ask me every morning, ‘Are you okay? You look really tired.’ I was just trying to survive, but I knew something wasn’t right.”

Plus, she began experiencing daily, low-level headaches. And oddly, she often felt like she couldn’t catch her breath—a condition called air hunger.

Two Autoimmune Diagnoses: Celiac and Hashimoto’s

It took until senior year for Jamie to find answers. She discovered she had celiac disease, an autoimmune disorder in which eating gluten—a protein found in wheat, barley, and rye—triggers the immune system to attack the small intestine.

She immediately cut gluten from her diet—or she thought she did. It wasn’t until she wrote a research paper in grad school that she truly understood the severity of her gluten sensitivity.

“I was being cross-contaminated still for two more years after the diagnosis, because I think that the education just wasn’t available back then when I got my diagnosis,” Jamie says.

“The difference between gluten intolerance, which is popular now, and celiac disease is that even like a crumb of gluten can affect someone with celiac disease,” she adds. “Versus, you don’t have that same breakdown in the microvilli if you just have gluten intolerance.”

With her diet dialed in, she still experienced symptoms such as fatigue, inflammation, and brain fog. Eventually, testing revealed high thyroid antibodies, leading to a Hashimoto’s diagnosis.

Hashimoto’s disease is an autoimmune condition in which the immune system attacks the thyroid gland, leading to chronic inflammation and often resulting in an underactive thyroid (hypothyroidism). For help, she started taking thyroid medication.

While Jamie was relieved to discover another piece of her health puzzle, she also realized she now had two autoimmune disorders. And despite diet and medication, frustrating symptoms persisted. Her headaches had progressed to a monthly migraine, timed exactly during ovulation each month.

During that time, Jamie experimented with diet to reduce inflammation, beyond going gluten-free. Within a few months of starting the Autoimmune Protocol (AIP) diet, she got pregnant—for her, a sign that her body was healing and she was on the right track.

Behind Her Symptoms: Mast Cell Activation Syndrome

As an anthropology student, Jamie dove into research in hopes of finding something to explain her lingering symptoms. She uncovered that fermented foods and bone broth could help with gut-healing and added those to her diet.

However, consuming heavy amounts of broth and fermented foods made her feel worse. When Jamie described her symptoms to her integrative practitioner, her provider replied:

“That sounds like mast cell activation syndrome.”

For Jamie, something clicked in hearing about mast cell activation syndrome (MCAS), which a colleague had had years ago. At the time, both worked in a moldy building.

Mast cell activation syndrome (MCAS) occurs when mast cells—a type of immune cell—become overreactive and release inflammatory chemicals like histamine unnecessarily. It’s often triggered by foods, mold, infections, or stress and can cause wide-ranging symptoms across multiple body systems.

More than anything else, MCAS made sense in the context of Jamie’s symptoms: the runny nose, headaches and migraines, air hunger, fatigue, and brain fog.

However, MCAS can look different for each person with an extensive list of possible symptoms: itching, rashes, hives, dermatographism, digestive issues, acid reflux, food intolerances, shortness of breath, wheezing, nasal congestion, asthma-like symptoms, low blood pressure, rapid heart rate, lightheadedness, fainting, palpitations, anaphylaxis, brain fog, headaches, migraines, dizziness, anxiety, irritability, depression, fatigue, heat intolerance, chemical sensitivity, smell sensitivity, menstrual irregularities, joint pain, muscle pain, and frequent infections.

While Jamie didn’t receive an official diagnosis for MCAS, she and her doctor proceeded with treating it based on symptoms.

“Testing for MCAS has its pluses and minuses,” she says. “If you need it for insurance, absolutely find a provider who is educated and can guide you on that appropriate testing. But for the majority of us, it’s just symptom-based… We have to keep peeling back the layers to find out what’s triggering the mast cells.”

Looking back, Jamie spotted a pattern of increasing symptoms in new moldy spaces: her college dorm, workplace, and various homes.

Treating MCAS

Jamie took a multi-pronged approach to calming her mast cells and symptoms:

Low-histamine diet – By choosing foods lower in histamines, Jamie reduced symptoms such as headaches and a runny nose.

Certain foods contain higher histamine levels or trigger histamine release, including fermented or aged foods like cheeses and vinegars, processed meats, citrus, tomatoes, avocados, and more. Even leftovers increase in histamine levels the longer they sit.

After two months on a low-histamine diet, her symptoms improved. Her monthly migraines stopped—a big clue she was on the right track.

Nervous system regulation – Mast cells are located near nerve endings throughout the body and respond to both physical threats and perceived stress. When the nervous system is in a chronic state of fight-or-flight (sympathetic overdrive), mast cells can become hypervigilant and start reacting.

Jamie focused on activities to calm her nervous system, including yoga, being in nature, and tools like Mast Cell 360’s Nervous System Reboot program.

“The nervous system piece was crucial—not just for symptoms, but even for being able to eat more foods again,” she says.

Mast cell stabilizing supplements – Jamie added supplements to help calm her mast cells, including quercetin, perilla, luteolin, resveratrol, and vitamin C.

“Once I got on those, I don’t even feel allergy season anymore.”

Environmental detox — Suspecting mold as a trigger, Jamie became intentional about where she lives and works. She noticed fewer headaches after leaving a moldy workplace.

“Mold’s the number one trigger we see of mast cell activation syndrome in our clinic at Mast Cell 360,” Jamie Frees Miller explains, referring to the clinic where she now works as a health coach.

She also switched to non-toxic personal care and cleaning products, began filtering her air and water, and avoiding known chemical triggers.

Over time, she also became more aware of her body’s signals.

“I know my telltale sign… a lot of people experience that histamine dump between 2 and 4 a.m.—so I know I’ve overdone it on the histamines because I’ll get that 3 a.m. wake-up,” she says.

Hope for Healing Autoimmunity and MCAS

These days, Jamie reports that headaches, air hunger, fatigue, brain fog, and chemical sensitivities are mostly in the past.

She eats a more varied diet without significant reactions and can tolerate exercise like yoga, kettlebells, rebounding, and walking.

If she does experience them now, she knows her “histamine bucket,” or the load in her body, has gotten too high.

“Symptoms are information—they’re the body’s way of talking to us,” she says.

Jamie’s experience led her to change her career from anthropology and archaeology to become a health coach. She is now a certified health coach and currently works as a health coach with Mast Cell 360, a clinic specializing in complex chronic conditions like mast cell activation syndrome (MCAS).

In her private coaching practice, she offers preconception and generational health coaching, particularly focused on mothers with autoimmunity or those navigating chronic conditions like MCAS.

She went on to write a memoir about being a first-time mother with autoimmunity: My Awakening: A Memoir and Pregnancy Guide from a First-Time Mom with Autoimmunity.

She continues with a slow mold detox and reducing her exposure to mold—knowing that’s a big symptom trigger for her.

Given her experience and all those she coaches, Jamie wants others to know that it’s possible to heal autoimmunity and MCAS.

“With the right support, you can totally, totally get better. Your health is worth it,” she says.

Find and follow Jamie:

Instagram (for preconception and generational health content)
Professional coaching: Mast Cell 360 — Jamie works as a health coach on the team

Jamie shares a few helpful links for those with MCAS:
Mystery symptom quiz: https://www.mastcell360.com/mystery-quiz
Nervous system blog: https://mastcell360.com/signs-of-nervous-system-dysregulation-with-mast-cell-activation-syndrome
Histamine intolerance and/or MCAS blog: https://mastcell360.com/histamine-intolerance-vs-mast-cell-activation-syndrome

Jamie is offering a coupon for a strategy session with Mast Cell 360: $50 off with code rebuildinghealth (all lowercase), no expiration date.
Book at https://www.mastcell360.com/application