If you’ve ever had a runny nose or itchy eyes when spring rolls around, you’re probably familiar with the term “histamine.” But what about histamine intolerance? Just like we can be sensitive to allergens in the air, we can also be sensitive to histamines taken in through the diet—this is called histamine intolerance, and it’s what we’re talking about today.

Histamine itself is a chemical messenger that plays many roles in the body, including immune defenses and gastric acid secretion. Histamine is released by the immune system (specifically mast cells and basophils) in response to allergens, such as those from the environment or foods.

Histamine is essential in controlled amounts in the body. However, when histamine levels rise, uncomfortable symptoms can occur. Allergy symptoms range from itchy, runny nose and eyes, to more severe reactions like anaphylaxis (which is a medical emergency and should not be taken lightly). Learn more here.

But histamine intolerance is less understood. Let’s dive into what it means, what symptoms to look for, and how to go about treating it.

What Is Histamine Intolerance?

Histamine intolerance is poorly understood overall, but can best be explained by malfunctioning histamine breakdown pathways in the GI tract.

Histamine is broken down by 2 main enzymes in the body, and the most active one is called diamine oxidase, or DOA. If DOA function is altered, histamines can build up in the body. Since histamine is created and released by the body, and taken in through diet, if DOA function is not working up to par, it can be common for your “histamine bucket” to overflow. This is when you’ll start to feel symptomatic after being exposed to allergens or high-histamine foods (more on what to look for in your medicine cabinet or your fridge if you’re trying to avoid high-histamine substances here).

Who is Susceptible to Histamine Intolerance?

Women with high estrogens may have a hard time with DOA enzyme function. Certain medications also alter the breakdown of DOAs, including NSAIDS and pain medications. Alcohol also alters the breakdown of histamine. Other factors that can impact DOA activity include genetic variants and microbiome imbalances. 

Symptoms of Histamine Intolerance

When the body does not break down histamine from foods, it can leak through the GI lining and enter the bloodstream, causing GI symptoms and sometimes systemic symptoms, like itchy skin.

How to Diagnose Histamine Intolerance

Histamine intolerance is very challenging to diagnose and unfortunately, some of the best foods are higher on the histamine scale, such as chocolate and aged cheeses. There is no way to avoid histamines through diet at 100%, however if you are someone who tends more towards allergic symptoms and have not found success with any other treatments, reducing high-histamine foods for a period of time and seeing how you feel would be a good place to start.

For those who struggle with chronic allergy symptoms or GI concerns with no other found cause, it is worth talking with your provider about the possibility of histamine intolerance. 

How to Reduce Symptoms of Histamine Intolerance

Reduce allergen exposure at home

Being aware of how to reduce your allergen exposure from the environment is a great place to start. To reduce indoor allergens, try:

• wet dusting,
• vacuuming,
• washing curtains and bedding weekly,
• and opening windows can help reduce allergens in indoor air.

While it might sound counterintuitive to open windows when being outside is what people with allergies often fear, indoor air is actually much more polluted than outdoor air.

Mast Cell Stabilizers

Instead of blocking histamine receptors by taking antihistamines, there is also the option using mast cell stabilizers to stabilize the cells in the body that release histamine, therefore preventing the release of histamine in the first place. A few examples of mast cell stabilizers are the herb nettle, and nutrients like vitamin C, quercetin, and NAC. More of a deep dive on supplements to consider adding to your routine for histamine intolerance can be found here.

DAO support

Supplementation with an animal-derived supplement containing the enzyme DAO can help break down histamine in the GI tract in those who have poorly functioning DAO pathways. DAO is quite expensive as a supplement and isn’t indicated in everyone with general allergy symptoms,, so working with a provider to figure out if this is the best option for you is recommended. Book an appointment with us here to see if this is a good fit for you.

Learn More About Histamine Intolerance

Learn more about histamines with this informative video.

For more info about histamine-containing foods, check out this list.

Dr. April Jones

Dr. Jones graduated from the National University of Natural Medicine in Portland, Oregon as a Doctor of Naturopathic Medicine and with a Master of Science in Nutrition degree. She believes that the most important part of any treatment plan is first establishing a solid foundation of health. This looks different for each patient and changes over time, and Dr. Jones’ guidance on your health journey will depend on your needs.