A Quick Introduction to the Low Histamine Diet

The low histamine diet — like the DASH diet or the gastroparesis diet — isn’t the kind of eating plan you try because you’re looking to drop a few pounds. It’s a medical treatment designed to reduce symptoms associated with a condition called histamine intolerance. And it’s something you do with the help of a team of doctors. Registered dietitian Amanda Igel, MS, RD, LD, explains.

What is the low histamine diet?

Let’s start by understanding what histamine is. You may be able to guess, if you’ve had to take antihistamines before.

“Histamine is a chemical substance in your mast cells, which is a certain type of white blood cell. Histamine helps your immune system respond to allergy triggers,” Igel explains. “If you have an allergy to a certain food, for example, histamine gets released by these immune cells in order to protect the body from what it perceives as a threat.”

Histamine sends your body a number of different signals in an effort to fend off an allergen. It opens up your blood vessels, while simultaneously constricting both your airways and your gastrointestinal (GI) tract. You also start generating mucus — hence, the runny nose.

Our body naturally produces histamine. There’s also histamine, in some quantity, in most of the foods we eat. We’d be overflowing with the stuff, but we have enzymes in our body — chief among them is an enzyme called diamine oxidase (DAO) — that break histamine down.

People living with a histamine intolerance have a problem with these enzymes. We’re not sure why it happens exactly. But we know that it’s no fun.

To be clear, a histamine intolerance isn’t an allergy. It’s what happens when you have an overabundance of histamine in your system — more than your body can comfortably tolerate. If your histamine levels have built up past a certain threshold, you’ll start experiencing unpleasant symptoms, like:

• Diarrhea or bloating.
• Nausea and vomiting.
• Headache.
• Runny or stuffy nose.
• Shortness of breath (dyspnea).
• Itching sensation.
• Rash, hives, or flushing.
• Painful menstrual periods.
• Low blood pressure (hypotension).
• A fast or irregular heart rate (arrhythmia).
• Swelling of the lips, tongue or throat.

Here’s the thing: There are a lot of conditions that can cause those symptoms. And some of them are quite serious. That’s why the low histamine diet isn’t something you undertake on your own.

“The low histamine diet is exclusively for people who are having symptoms and have had the extensive GI and allergy workups,” Igel stresses.

Histamine intolerance is what’s known as a diagnosis of exclusion: It’s what’s left after all the other possibilities have been explored and ruled out. Some of the conditions that your provider needs to rule out include inflammatory bowel disease (IBD), celiac disease and mast cell disorders like mastocytosis and mast cell activation syndrome (MCAS).

There are also certain medications that can cause histamine intolerance. And — just to make things a little extra complicated — histamine intolerance can also be a side effect of another underlying condition. It’s possible, for example, to have both Crohn’s disease and histamine intolerance.

“The low histamine diet is all about limiting the foods that are naturally higher in histamine, as well as certain foods that can make it harder for the DAO enzyme to do its job,” Igel explains. “It’s not an elimination diet, meaning we’re not trying to get rid of all the histamine in the world. We’re trying to limit the exposure so that the enzymes have a chance to at least break some of it down.”

Histamine intolerance isn’t a life-threatening condition. There are, no doubt, people around the world with histamine intolerance who have no idea or attribute their symptoms to other conditions. And the low histamine diet doesn’t treat histamine intolerance. But — done properly — it can improve quality of life.

“Nobody wants to have diarrhea,” Igel acknowledges. “Nobody wants heart palpitations or rashes. The low histamine diet is about reducing the impact those symptoms have on your daily life.”

Benefits of a low histamine diet

Histamine intolerance is a rare condition. As of right now, experts believe it only affects about 1% of the U.S. population. But histamine levels are highly variable, which makes the disease extremely difficult to diagnose. It’s very possible the numbers are higher.

Right now you might be thinking, “I have some of those symptoms, maybe I should try a low histamine diet.” That’s not a good idea, Igel states. That’s because, unlike an elimination diet — where you cut out a certain type of food and see what happens — a low histamine diet is much more specialized. And there are a lot of foods that cause symptoms.

“People living with histamine intolerance, they can eat a certain food one day and not the next,” Igel explains, “Or maybe they can tolerate certain high histamine foods but not others. The symptoms can also be seasonal because the allergens in the environment impact the food we eat.”

A true low histamine eating plan isn’t static. It adapts alongside a person’s individual circumstances. That’s why, Igel notes, it’s important to have a dietitian or healthcare provider monitoring you when you’re on a low histamine diet.

“They need to monitor you to make sure you’re not malnourished or at risk for malnutrition,” she stresses. “A low histamine diet isn’t about weight loss or restriction. It’s about reducing uncomfortable symptoms without needlessly restricting what a person eats. And that’s a delicate balance.”

What to keep in mind on a low histamine diet

If you search “low histamine diet,” the internet will cough up a lot of information about what foods to limit or eliminate. That information may sometimes be correct — but that advice isn’t tailored to you the way it would be if you’d been properly diagnosed.

“It’s easy to go down the rabbit hole,” Igel notes. “But it isn’t helpful. Everybody has a spectrum. People with histamine intolerance can have very different thresholds as far as what they can and can’t handle. And there’s no great way of measuring histamine levels in food.”

Here are a few principles that people on a low histamine diet generally follow:

Fresh, whole and unprocessed foods are preferable

When we ferment, cure or age food, we’re allowing bacteria to break it down. That’s going to raise the food’s histamine levels. People with histamine intolerance will likely do better with food that’s at peak freshness. That means shopping with an eye for whole and unprocessed foods. And even then, it’s often important to avoid certain fruits and vegetables, as well as food that’s very ripe. Examples of foods to avoid include:

• Alcohol (wine, beer and champagne).
• Aged or processed meat (sausage, cold cuts and bacon).
• Aged, smoked, unpasteurized and blue cheeses.
• Fermented foods (kimchi, kefir and sauerkraut).
• Canned, marinated, salted, dried, smoked, or pickled foods.
• Vegetables (tomatoes, eggplant and spinach).
• Tropical fruit (pineapple, bananas, papaya and citrus fruits).
• Fish or shellfish that isn’t fresh-caught or frozen (like canned mackerel, tuna, sardines or herring).
• Strawberries.
• Nuts and peanuts.
• Legumes (lentils and beans).
• Soy products.
• Licorice.
• Chocolate.
• Additives (like colorants and preservatives).

To be clear, this list isn’t exhaustive. All foods have some histamine, so the level of restriction involved in a low histamine diet varies from person to person, depending on both the nature of their symptoms and their personal histamine threshold.

Food storage matters, too

You want to store your food in a way that minimizes bacteria production. That means refrigeration and freezing are the way to go. Canned and shelf-stable foods aren’t usually recommended on a low histamine diet.

Cook your own food

It’s not just what you eat that matters on a low histamine diet. How it’s prepared is just as important. Grilling a food, for example, produces more histamine than braising or steaming does. Eating out may be difficult on a low histamine diet because you can’t control the ingredients used in the dish, much less the storage or preparation techniques.

Keep a food diary

As we mentioned earlier, people living with histamine intolerance aren’t in the same boat as people living with a condition like celiac disease, who become ill any time they eat food containing gluten. A person with histamine intolerance is going to react differently to the same foods, depending on where their histamine levels are. So, it’s important to use a food journal to track what you eat, how much of it you eat — and any symptoms you have throughout the day — very carefully.

Who should avoid the low histamine diet

As you’ve no doubt realized by now, a low histamine eating plan is extremely restrictive. That’s not a good idea for everybody with histamine intolerance.

“If you have a history of disordered eating or if you’ve been diagnosed with an eating disorder, it’s best to manage the symptoms you’re experiencing with things like medical antihistamines or topical steroids,” Igel suggests. Focusing on all the restrictions instead of the true goal (symptom management) can trigger an eating disorder relapse or allow one to develop for the first time.

Remember: The low histamine diet isn’t a weight loss plan — if anything, your efforts need to be directed at staying nourished and maintaining your weight.

Takeaway

The low histamine diet is a medical diet for people who’ve been formally diagnosed with a rare condition called histamine intolerance.

Despite the name, histamine intolerance isn’t an allergy — it’s an overabundance of the chemical our immune system produces to respond to allergens. That overabundance happens because the enzymes that break down the histamine aren’t working properly. It can be caused by a number of underlying conditions and requires a team of healthcare providers to diagnose and manage.

Histamine is in our bodies and the food we eat, so it can’t be eliminated from our diet. You also can’t easily measure or predict the amount of histamine in a food, which means that a person with histamine intolerance may experience inconsistent, seasonal, or fluctuating symptoms.

As a result, people following a low histamine diet reduce their histamine intake as much as possible, allowing their faulty enzymes have a chance to catch up and break down all the excess. This, theoretically, can ease uncomfortable symptoms and improve quality of life.

The low histamine diet is extremely restrictive and has to be closely monitored by a dietitian to protect against malnutrition. The eating plan doesn’t promote weight loss and people living with or recovering from eating disorders are strongly discouraged from attempting it under any circumstances.