Hi Everyone,
Dr. Storage here.
This week, we picked a topic that was inspired by YOU.
A reader wrote in last week with a story that honestly gave me pause.
This individual had seen specialists at top institutions for gas and bloating..
Yet it felt like they were missing a piece of the puzzle.
Their story:
"I realized I was avoiding exactly the fruits on the high histamine list… I realized I may have a histamine issue and took some DAO enzymes, which reduced my gas by about 40%, and I had a flat stomach for the first time in years... I am surprised that this is not something that any of my physicians have mentioned."
First, let me validate this: A 40% bloating improvement is massive (shoutout for quantifying it!)
If a simple enzyme changed your life when major hospitals missed it, it’s a sign that we need to talk more about Histamine Intolerance (HIT).
We love hearing from you. If you are struggling with a symptom that no one can explain, reply to this email.
We read them, and your story might just be the spark for our next deep dive.
Now, let’s talk about why your "healthy" leftovers and avocados might be the source of your bloat.
Why You Should Read This Now
HIT is sneaky: Histamine intolerance can resemble irritable bowel syndrome (IBS), allergies, or anxiety, making it incredibly difficult to diagnose.
The "healthy" trap: Many foods we encourage (spinach, fermented foods, avocados) are high in histamine. If you have HIT, "eating clean" can actually make you feel worse.
The DAO connection: We’ll explain exactly why these enzymes worked for our reader, and what you should do if you’re dealing with something similar.
Today’s Opponent:
Histamine Intolerance (HIT)
To understand histamine intolerance, you have to forget about "allergies" for a second.
An allergy is an immune reaction (like a peanut closing your throat).
HIT is a metabolic issue. It’s a math problem.
Imagine your body is a bucket.
→ Water flowing in: Histamine from food (aged cheese, wine, spinach) and histamine produced by your own gut bacteria.
→ The drain: An enzyme called DAO (Diamine Oxidase) that breaks histamine down.
→ The problem: If your "drain" is clogged (low DAO) or the water is pouring in too fast (high histamine diet), the bucket overflows.
That overflow looks like: Bloating, headaches, flushing, racing heart, and nasal congestion immediately after eating.
Our reader mentioned that taking DAO enzymes gave them a flat stomach. This makes perfect scientific sense.
DAO is the primary enzyme your body uses to break down ingested histamine. It lives in the lining of your small intestine (the "brush border").
Why Might Your DAO Be Low?
If you take a supplement and feel better, you are treating the symptom (the overflow).
But we want to treat the cause (the clogged drain). Common reasons for low DAO include:
👉 Gut Inflammation: If the lining of your small intestine is inflamed or damaged, you cannot produce enough DAO. This is why the reader’s bloating is a key clue. Small intestinal bacterial overgrowth (SIBO) often causes HIT.
👉 Genetics: Some people naturally produce less DAO.
👉 Medications: NSAIDs (ibuprofen), antidepressants, and some antibiotics can block DAO production.
👉 Alcohol: Is a double whammy. It’s high in histamine and it blocks the enzyme that breaks it down.
The Sneaky Healthy Culprits
If you suspect this is you, look at your plate. Are you eating these high-histamine foods?
Fermented foods: Sauerkraut, kimchi, kombucha (Irony alert: We love these for the microbiome, but for HIT patients, they are kryptonite).
Aged foods: Cured meats, aged cheeses.
Vegetables: Spinach, eggplant, tomato, avocado.
Leftovers: Histamine builds up in food as it sits in the fridge.
“If you eat a salad with spinach, avocado, and tomato, and feel worse, don't gaslight yourself. You aren't crazy. You might just have a full histamine bucket. Listen to your body, not just general health advice."
“The key takeaway here is the location of the defect: DAO is produced in the intestinal villi. If you have unrecognized celiac disease, Crohn’s, or SIBO, your DAO production drops. Treat the underlying GI inflammation, and often the histamine tolerance returns."
Your HIT Gameplan
Here’s the roadmap Dr. Tabibian and I use:
The "Low Histamine" Trial (2 Weeks Only): Eat fresh. Cook meat and eat it immediately. Avoid the high-histamine list above. If you feel significantly better, you have your diagnosis. Warning: do not do this forever. Restrictive diets can damage the microbiome long-term.
Check for SIBO: Since DAO lives in the gut lining, you must rule out SIBO. If bacteria are overgrowing in your small intestine, they are potentially damaging the very cells that make the enzyme you need.
Support Your Liver: Your liver is responsible for breaking down histamine that escapes you gut (via a different enzyme called HNMT). If your liver is sluggish or fatty, your histamine load stays high.
What’s On Your Mind?
Respond to this email and let us know!
As gastroenterologists, we definitely have a lot to talk about when it comes to your gut health and well-being. But we can’t always get to everything (you know… like coffee enemas)! So reply directly to this email or DM us on TikTok below and maybe YOUR topic will be featured soon!
