Life Extension Magazine®

Plant-Based Solution for Food

A plant-derived supplement provides the enzyme that breaks down histamine, a major cause of food sensitivity.

Scientifically reviewed by: Gary Gonzalez, MD, in January 2025. Written by: Eric Holitzer.

Food sensitivities or intolerances affect an estimated 20% of the population.¹

A frequently undiagnosed example is histamine intolerance.² Many people struggling with abdominal bloating and pain, diarrhea, gas, headaches, and other symptoms have no idea that foods containing histamine may be the cause.³

Avoiding dietary histamine is difficult. But there is another option for managing histamine intolerance.

In clinical studies, oral intake of the enzyme diamine oxidase (DAO) breaks down histamine in the digestive tract. This can significantly reduce or prevent symptoms caused by sensitivity or intolerance.^4-9

Most commercially available DAO is derived from pigs.⁸

A new plant-derived DAO makes this relief available to a wider range of people with histamine intolerance, including vegans, vegetarians, and anyone who avoids consuming pork products.²

What Is Histamine Intolerance?

Histamine is a bioactive amine/neurotransmitter that regulates many physiological functions, including those in the brain, gut and immune system.

Histamine can be formed in the human body from the amino acid histidine, produced by bacteria in our microbiome. It’s also ingested from many food products.

As part of its immune function, histamine stored by immune cells is released in response to foreign substances² such as pollen or animal dander. This histamine acts like a trigger to turn on inflammation. The result is sneezing, itchy skin and eyes, and other symptoms associated with allergic reactions.²

That’s why antihistamine medications are often used to minimize allergy symptoms.

However, histamine intolerance is not an allergy. In an allergic reaction, our own cells release histamine.²

In histamine intolerance, the histamine degradation system in the gut is unable to process histamine consumed in foods.

This accumulated histamine can cause gastro-intestinal symptoms, including nausea, bloating, abdominal pain, diarrhea, gas, or constipation. Body-wide symptoms like headache, dizziness, a feeling of brain fog, itchy skin or rash, hives, nasal congestion, and sneezing may also occur.²

In this situation, the proper function of diamine oxidase (DAO) is key in preventing histamine accumulation.² DAO is a histamine-degrading enzyme.

Histamine-Containing Foods

A histamine-free diet is virtually impossible because many foods and drinks contain histamine, with the largest amounts found in foods or drinks that have been fermented, aged, or preserved, including:²

Cured or fermented meats, such as some dried sausages and deli meat,
Canned, preserved, or smoked fish or shellfish,
Aged cheeses, and
Wine and beer.

Many other foods contain smaller amounts of histamine or histamine-like chemicals, including tomatoes, spinach, eggplant, nuts, legumes, bananas, pineapple, strawberries, and citrus fruits.

What Causes Histamine Intolerance?

The enzyme diamine oxidase (DAO) is the main histamine-degrading enzyme in the digestive tract, responsible for degrading histamine from foods. When our body produces enough DAO, histamine in food is metabolized before it causes problems.²

But DAO production and activity can be lower in some people. In these people with diminished ability to break down histamine, ingestion of histamine-rich foods can cause a wide array of symptoms known as histamine sensitivity or intolerance.

DAO to the Rescue

Avoiding foods high in histamine may help control symptoms in some people. But completely eliminating histamine from the diet is often impossible.

The good news is that there is another option: The enzyme diamine oxidase can be taken orally with food to help digest histamine. Human studies show that DAO intake can help reduce or prevent symptoms associated with histamine intolerance.^4-9

One clinical study enrolled participants with DAO deficiency and frequent migraine headaches. Taking DAO three times a day before each meal significantly reduced the number and duration of headache episodes and reduced the number of subjects needing to take pain medication.⁴

In another study, patients with signs of histamine intolerance and low DAO levels on blood tests were given DAO before meals for a month. This significantly reduced frequency and severity of gastrointestinal histamine-related symptoms such as bloating, pain, diarrhea, and fullness.⁸

During a follow-up period, when DAO was no longer taken, symptoms increased again.

These and other studies suggest that DAO intake can be an effective means of managing symptoms of histamine intolerance.

Plant-Derived DAO

The clinical studies cited so far have used DAO derived from pig kidney. However, a vegetarian-friendly novel DAO has been isolated from pea sprouts.

The plant-derived DAO has a capacity of breaking down histamine similar to its porcine counterpart.¹⁰

This vegetarian formulation allows those who avoid meat or pork-derived products to use DAO to help prevent symptoms of histamine intolerance.

What You Need To Know

Help For Histamine Intolerance²

Some people have a sensitivity to histamine, a bioactive amine contained in many different types of foods and drinks.
In people with histamine intolerance, consuming histamine-rich foods can trigger gastrointestinal symptoms like abdominal pain and bloating, diarrhea, gas, and nausea, and/or systemic effects such as headaches, itchy skin, and brain fog.
People who suffer from histamine intolerance may be deficient in an enzyme called diamine oxidase (DAO) that normally breaks down histamine in the gut, preventing histamine accumulation, which may cause symptoms.
In these individuals, oral intake of DAO has been clinically shown to help prevent or reduce symptoms of histamine intolerance.
Supplemental DAO is typically derived from pig kidneys, but a new plant-based DAO derived from pea sprouts allows a larger number of people to experience relief from histamine intolerance symptoms.

Summary

One food sensitivity that often goes undiagnosed is histamine intolerance.

Histamine consumed in foods including wine, beer, canned and preserved fish, cured and fermented meats, and aged cheeses can cause gastrointestinal problems, headaches, and other symptoms.

Some people are prone to histamine intolerance because of a deficiency of an enzyme called DAO that breaks down histamine in the digestive tract.

Taken orally, a novel plant-derived DAO may help reduce or prevent symptoms of histamine intolerance.

Is It Histamine Intolerance or Another Cause?

Histamine intolerance is one of many conditions that can cause symptoms after consuming specific foods.¹¹

Others may include:

True food allergies, which can be life-threatening, with immediate allergic reaction occurring soon after–within minutes–of ingesting the trigger foods,
Intolerances or sensitivities to gluten, dairy, soy, and other food components, with symptoms typically occurring some hours after ingestion,
Celiac disease, an autoimmune condition,
Tyramine sensitivity, a reaction to an amino acid in foods due to use of MAO inhibitor drugs, and
Disorders like irritable bowel syndrome or inflammatory bowel disease.

Distinguishing between these causes of food-triggered symptoms can be tricky. If you suspect you may have histamine intolerance or another one of these conditions, your physician can help evaluate that diagnosis.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.

References

Tuck CJ, Biesiekierski JR, Schmid-Grendelmeier P, et al. Food Intolerances. Nutrients. 2019 Jul 22;11(7).
Comas-Baste O, Sanchez-Perez S, Veciana-Nogues MT, et al. Histamine Intolerance: The Current State of the Art. Biomolecules. 2020 Aug 14;10(8).
Jochum C. Histamine Intolerance: Symptoms, Diagnosis, and Beyond. Nutrients. 2024 Apr 19;16(8).
Izquierdo-Casas J, Comas-Baste O, Latorre-Moratalla ML, et al. Diamine oxidase (DAO) supplement reduces headache in episodic migraine patients with DAO deficiency: A randomized double-blind trial. Clin Nutr. 2019 Feb;38(1):152-8.
Komericki P, Klein G, Reider N, et al. Histamine intolerance: lack of reproducibility of single symptoms by oral provocation with histamine: a randomised, double-blind, placebo-controlled cross-over study. Wien Klin Wochenschr. 2011 Jan;123(1-2):15-20.
Manzotti G, Breda D, Di Gioacchino M, et al. Serum diamine oxidase activity in patients with histamine intolerance. Int J Immunopathol Pharmacol. 2016 Mar;29(1):105-11.
Okutan G, Sanchez Nino GM, Terren Lora A, et al. Exogenous Supplementation with DAO Enzyme in Women with Fibromyalgia: A Double-Blind Placebo-Controlled Clinical Trial. J Clin Med. 2023 Oct 10;12(20).
Schnedl WJ, Schenk M, Lackner S, et al. Diamine oxidase supplementation improves symptoms in patients with histamine intolerance. Food Sci Biotechnol. 2019 Dec;28(6):1779-84.
Yacoub MR, Ramirez GA, Berti A, et al. Diamine Oxidase Supplementation in Chronic Spontaneous Urticaria: A Randomized, Double-Blind Placebo-Controlled Study. Int Arch Allergy Immunol. 2018;176(3-4):268-71.
AB-Biotek. Technical Specs and Company Documentation.
Zopf Y, Baenkler HW, Silbermann A, et al. The differential diagnosis of food intolerance. Dtsch Arztebl Int. 2009 May;106(21):359-69; quiz 69-70; 4 p following 70.