Histamine Intolerance and IBS: Are They Connected?

Michael Eisenwasser 4 min read

If you have IBS and nothing seems to help, histamine might be part of the picture.

Many people with histamine intolerance were first diagnosed with IBS. The symptoms overlap almost completely: bloating, cramping, diarrhea, constipation, abdominal pain. Standard IBS treatments often don't help everyone, and histamine could be one reason why.

The symptom overlap

Histamine intolerance and IBS share most of the same digestive symptoms:

• Bloating and distension
• Abdominal pain and cramping
• Diarrhea (sometimes urgent)
• Constipation (or alternating between the two)
• Nausea
• Gas
• Feeling like food isn't digesting properly

The difference is what's causing them. With histamine intolerance, these symptoms happen because histamine irritates the gut lining and affects gut motility. With IBS, the cause is often unclear, which is part of why it's so hard to treat.

Why so many people have both

Some people genuinely have both conditions. But in many cases, what looks like IBS is actually histamine intolerance that was never identified.

IBS is a diagnosis of exclusion. If your tests come back normal but you still have chronic digestive issues, you get labeled with IBS. The problem is that histamine intolerance doesn't show up on standard tests, so it gets missed.

There's also a real connection between the two. Gut issues can reduce DAO enzyme production. DAO is made in your intestinal lining, so when that lining is compromised, you can't break down histamine as well. This creates a cycle: gut issues lead to histamine buildup, which causes more gut issues.

How histamine affects your gut

Histamine does several things in your digestive system:

Increases gut motility. High histamine can speed up digestion, leading to diarrhea and urgency. This is why some people need to run to the bathroom after eating high-histamine foods.

Causes inflammation. Histamine triggers inflammation in the gut lining, which leads to pain, cramping, and bloating.

Increases permeability. Histamine can make your gut lining more permeable ("leaky gut"), allowing particles through that shouldn't get through. This triggers more immune reactions and more histamine release.

Affects fluid secretion. Histamine influences how much fluid your gut secretes, which affects stool consistency.

Signs your IBS might be histamine-related

Consider histamine if:

• Your symptoms are worse after certain foods (especially fermented, aged, or leftover foods)
• You have other histamine symptoms beyond digestion (headaches, flushing, itching, anxiety)
• Your symptoms fluctuate with your menstrual cycle
• Standard IBS treatments haven't helped
• Low-FODMAP diet helped somewhat but didn't solve everything
• Your symptoms are worse when you're stressed or haven't slept well

For a full list of histamine symptoms, see common symptoms of histamine intolerance.

The low-FODMAP connection

Many people with IBS try the low-FODMAP diet and get partial relief. Interestingly, the low-FODMAP diet eliminates some high-histamine foods by accident, which might explain part of why it helps.

But low-FODMAP doesn't specifically target histamine. You might be avoiding wheat (which can affect histamine, see is gluten high in histamine) while still eating aged cheese, canned fish, or leftovers that are high in histamine.

If low-FODMAP helped but didn't fully resolve your symptoms, adding histamine awareness might be the missing piece.

What helps

If histamine is contributing to your digestive issues:

Eat fresh. Histamine builds up as food ages. Eating freshly prepared food instead of leftovers can make a big difference. See why leftovers can trigger histamine symptoms.

Reduce high-histamine foods. Fermented foods, aged cheese, cured meats, certain fish, and alcohol are common triggers. See foods with high histamine levels.

Support DAO. Taking a DAO supplement 15-30 minutes before meals can help break down dietary histamine.

Address gut health. If your gut lining is damaged, it can't produce DAO effectively. Working on gut healing (while avoiding histamine-producing probiotics, see why probiotics can make histamine worse) may help long-term.

Track patterns. Digestive symptoms are often delayed, making it hard to connect cause and effect.

It's not always one or the other

You might have IBS and histamine intolerance. You might have histamine intolerance that was misdiagnosed as IBS. Or histamine might be one of several factors affecting your digestion.

The only way to know is to test. Reduce histamine for a few weeks while keeping everything else consistent. If your digestive symptoms improve, histamine is worth exploring further.

Logging meals and digestive symptoms over time can reveal patterns that aren't obvious day to day, especially when reactions are delayed. For a lot of people, figuring out the histamine connection is what finally makes their "IBS" manageable.

Track your symptoms and discover patterns with Histamine Tracker. Includes a database of 1,000+ foods with histamine ratings.