Is Gluten the Missing Link in Autoimmune Disease?

You don't need celiac disease for gluten to light up your immune system.

I was at the farmers market with my kids this weekend when I spotted my favorite gluten-free bakery, Knead Love. I grabbed a loaf of gluten-free sourdough and a few gluten-free bagels.

Then the founder, Sarah, tapped me on the shoulder. She follows my work. (And me on Instagram.) Turns out I follow her too. I love her bread.

That's when she told me her story. Serious autoimmune symptoms. A long, frustrating road to a diagnosis. And going gluten-free cleared up most of them. Knead Love grew out of her own health journey.

I posted a photo of us. But her story stayed with me, because I hear it all the time. Mostly from women. (Nearly 80% of people with autoimmune disease are women, per Emerging Infectious Diseases, 2004.¹) Years of symptoms. Symptoms that get brushed off. In one survey, 64% of women with autoimmune disease said they'd been told they were overly worried about their health.² And blood work that comes back normal, because not every autoimmune disease shows up on a blood test.

Most doctors were never trained to connect the dots between the gut, wheat, and autoimmune disease beyond celiac. That's a huge missing link.

In functional medicine, we hear: “You just tell everyone to cut out gluten and dairy.” Not exactly. What we suggest is a 30-day experiment, often with wheat and dairy. Because of what we see in patients every day. And because the science shows these foods can trigger symptoms that get missed or mistreated.

Today: how gluten triggers autoimmunity, and what to do about it. Let's do it!

What to know: Gluten can trigger your immune system even if you don't have celiac disease.

The old assumption: Gluten only matters if you have celiac disease.

The new reality: celiac is the tip of the iceberg.

Celiac disease is an autoimmune reaction to gluten. It affects about 1% of people worldwide.³ But there's a bigger group: people who test negative for celiac and still react to wheat. It's called non-celiac gluten sensitivity. It's a real diagnosis, and it's under-recognized.

In an Italian study of people with non-celiac wheat sensitivity, 29% had another autoimmune disease, mostly Hashimoto's. And 46% tested positive for antinuclear antibodies, a marker of autoimmunity, versus 24% of people with celiac. About 9 in 10 were women.⁴

❝ 46% of people with non-celiac wheat sensitivity tested positive for an autoimmune marker. Nearly double the rate in celiac disease.

One center, and it shows a link, not proof. Which is why you run the experiment on yourself.

How gluten gets in the door

• Gluten is tough to digest. One gliadin fragment survives every human digestive enzyme tested.⁵
• Gliadin binds a receptor on your gut lining and triggers zonulin.⁶ Zonulin is the signal that opens the tight junctions, the seals between your gut cells.
• In gut biopsies, gliadin loosened the barrier in everyone tested, and most in people with active celiac or gluten sensitivity.⁷
• Then bacterial fragments and food particles slip through, right next to most of your immune cells.⁸ 70% of your immune system lives in the gut.

In people with wheat sensitivity, blood markers show gut cell damage and immune activation. Healthy controls don't.⁹ Scientists still debate how much of this is a leaky barrier versus direct immune activation. Either way, you get an immune system on high alert.

Gluten isn't the only thing that loosens the seal. Stress,¹⁰ heavy drinking,¹¹ and NSAIDs like ibuprofen¹² can too.

What about our wheat?

You've probably heard US wheat is a genetically modified (GM) “Frankenwheat.” It isn't. No GM wheat is grown commercially in the US.¹³ Most modern wheat is “semi-dwarf”: shorter-stalked varieties developed through conventional breeding. Over 90% of varieties bred for the Eastern and Central US carry these genes.¹⁴ And the protein content of US wheat shows no upward trend in a century.¹⁵

What changed is how much of it we eat:

• Wheat flour per person annually: 110 lb in 1972, 147 lb in 1997. Down to about 127 lb now.¹⁶
• Vital wheat gluten, added to foods, per person: 3X since 1977.¹⁷

So overall the same amount of gluten in the wheat itself. But we get far more exposure.

It doesn't always show up in your gut

Your immune system is everywhere in your body, so the symptoms can be too. For a lot of people, the gut is quiet:

• Thyroid: Hashimoto's was the most common autoimmune disease in that wheat sensitivity study. In a small pilot of 34 women with Hashimoto's, the ones who went gluten-free for 6 months had lower thyroid antibodies.¹⁸ A 2025 review of 3 trials couldn't confirm it. Too small to call.¹⁹
• Skin: In 17 people with non-celiac gluten sensitivity, itchy eczema-like and psoriasis-like rashes cleared about a month after going gluten-free.²⁰ Psoriasis also carries about 2.2x the odds of celiac disease.²¹
• Joints: A 2025 genetic analysis of 500,000+ people linked a gluten-free diet to lower rheumatoid arthritis risk.²²
• Head and gut: migraines, brain fog, bloating.

Given all the ways gluten sensitivity can show up, the downside of a 30-day experiment is close to zero.

What to do: Run the experiment, track it, and get help if you have autoimmune disease.

One caution first. If celiac runs in your family, or you have gut symptoms, ask your doctor for a celiac blood test before you cut gluten. It only works while you're eating it.²³

1️⃣ Cut all wheat and gluten for 30 days.

If you're only going to eliminate one thing, make it this one. Read labels. Gluten hides in more places than bread.

• Skip: wheat, rye, barley, bread, pasta, crackers, cereal, baked goods
• Watch for: soy sauce, salad dressings, sauces, soups
• Choose certified gluten-free oats

2️⃣ Track your symptoms with the PSI at four points.

Lots of people do an elimination diet and never document it. Then it's hard to know what changed. I can't remember what I had for lunch last Tuesday, let alone how bad my headache was three weeks ago. Take the Parsley Symptom Index (PSI):

• Before you start
• 2 weeks in
• 2 weeks after that (the end of your 30 days)
• 2 weeks after that (after reintroduction)

Sometimes the change is obvious. Sometimes it's subtle. The tracker catches what memory misses.

3️⃣ Reintroduce gluten over 2 weeks.

Add it back slowly and watch what happens.

• Start with one serving of wheat, like bread or pasta
• Wait a day or two, and note any symptoms
• Continue to eat wheat every 2 days over 2 weeks and note symptoms

If your symptoms come back, you have your answer.

4️⃣ Still have symptoms? Test other foods, one at a time.

Dairy, eggs, and nightshade vegetables (tomatoes, potatoes, peppers, eggplant) are the usual suspects. Don't cut them all at once. It's miserable and it muddies the results. Run the same experiment you did with gluten. Add asthma and chronic sinus infections to your symptom list. They aren't autoimmune, but they're signs of chronic inflammation.

5️⃣ If you have an autoimmune condition, work with a doctor.

Ask about food sensitivity testing. In my practice, I use the KBMO test most often. I don't run it on everyone, because it isn't always useful or accurate. For my autoimmune patients, it can be vital. Think of it as a map, not a diagnosis. The elimination and reintroduction confirm it.

Ask about a gut-healing protocol too: resealing the gut lining and supporting your microbiome, which shapes your gut immune system. And don't change any autoimmune medication without your prescribing doctor.

6️⃣ Meditate every day.

Stress loosens the gut barrier too. In healthy volunteers, giving a public speech was enough to do it.¹⁰ Daily meditation activates your parasympathetic nervous system, and mindfulness has been linked to lower inflammatory markers like CRP.²⁴ Start with 10 minutes every morning.

The goal: You're not signing up for a draconian diet forever. Many people reintroduce foods successfully, or drop only one or two.

Immunosuppressive medications can be a game changer. But they treat the fire, not the spark. In my experience, they can stop working over time, and then you add another. That's why in my practice we look for the trigger: food, gut, stress, and more. Often we can turn the activity down, and sometimes into remission.

Living Longevity

Last week I saw Harry Styles perform at Madison Square Garden. He's playing 30 shows there over two months. The night of the concert, I posted on IG that Harry is living longevity. Here's what I meant.

First, the level of physical stamina to get through just one of these shows is immense. You can see the sweat pouring down his body, his shirt is soaked, and the veins in his neck are bulging. He wipes his face and drinks from a huge metal water bottle. (No plastic! No booze!) The same goes for his dancers and his mostly female band. The cardiovascular exertion of performing at peak intensity for two hours is impressive even once, let alone night after night.

I found myself wondering what his sleep routine is, if he has a Whoop, if he takes supplements or meditates, or if he just gets up every morning and does it all over again, and that's his practice.

Second, and just as important, his music has evolved. I went to his show at MSG two years ago, and I remember the screaming 16-year-olds as much as anything, losing their minds song after song, happily awash in the pastel pop vibes of his music. This time, the vibe was much darker, more electronic, more serious. The crowd was older. He performed maybe two of his best-known hits, and the rest was new. He wasn't recycling himself. He was using the same skill set and talents but applying them in a totally new way.

Cognitive longevity has been shown to depend not just on our cholesterol levels and blood sugar but also on our willingness to do new things, keep learning, and keep working. People with the highest lifetime mental enrichment had a 38% lower risk of Alzheimer's and developed it about 5 years later, according to research published this year in Neurology.²⁵

So this week, for your longevity, in addition to lifting heavy, challenge yourself to do one thing that's new, cognitively uncomfortable, or surprising. Play a new game. Write with your non-dominant hand. Read a book or an article on a topic you know nothing about. You already have the skill set and the talents. You just have to keep applying them in new ways to keep your mind, your heart, and your body alive.

One more thing...

Want a baseline to understand your symptoms and get a score for how you really feel? Take the Parsley Symptom Index today, then retake it in two weeks.