If you’ve suffered from seasonal allergies or food allergies, you may have noticed that antihistamine medications like Zytrec, Allegra or Benedryl provide quick relief of your symptoms. This is because histamine’s role in the body is to cause an immediate inflammatory response.

The buildup of histamine is what gives you a headache and leaves you feeling flushed, itchy and miserable. This is part of the body’s natural immune response, but if you don’t break down histamine properly, you could develop what we call histamine intolerance.

How does the body break down histamine?

Once formed, histamine is either stored or broken down by an enzyme. Histamine in the central nervous system is broken down primarily by histamine N-methyltransferase (HMT), while histamine in the digestive tract is broken down primarily by diamine oxidase (DAO).

Though both enzymes play an important role in histamine break down, the American Society for Clinical Nutrition found that DAO is the main enzyme responsible for breaking down ingested histamine. So if you’re deficient in DAO, you likely have symptoms of histamine intolerance.

Causes of Low DAO (Diamine Oxidase)

  • Gluten intolerance
  • Leaky gut (a.k.a. intestinal permeability)
  • Bacterial overgrowth (SIBO)
  • DAO-blocking foods: alcohol, energy drinks, and tea
  • Genetic mutations (common in people of Asian-descent)
  • Inflammation from Crohn’s, ulcerative colitis, and inflammatory bowel disease
  • Medications:
    • Non-steroidal anti-inflammatory drugs (ibuprofen, aspirin)
    • Antidepressants (Cymbalta, Effexor, Prozac, Zoloft)
    • Immune modulators (Humira, Enbrel, Plaquenil)
    • Antiarrhythmics (propanolol, metaprolol, Cardizem, Norvasc)
    • Antihistamines (Allegra, Zyrtec, Benadryl)
    • Histamine (H2) blockers (Tagamet, Pepcid, Zantac)

Although histamine blockers, this class of acid-reducing drugs seem like they would help prevent histamine intolerance. But, these medications can actually deplete DAO levels in your system.

Common Symptoms of Histamine Intolerance

  • Headaches/migraines
  • Difficulty falling asleep
  • Hypertension
  • Vertigo or dizziness
  • Arrhythmia, or accelerated heart rate
  • Difficulty regulating body temperature
  • Anxiety
  • Nausea, vomiting
  • Abdominal cramps
  • Flushing
  • Nasal congestion, sneezing, difficulty breathing
  • Abnormal menstrual cycle
  • Hives
  • Fatigue
  • Tissue swelling

What Causes High Histamine Levels?

  • Allergies (IgE reactions)
  • Bacterial overgrowth (SIBO)
  • Leaky gut (a.k.a. intestinal permeability)
  • GI bleeding
  • Fermented alcohol like wine, champagne, and beer
  • Diamine Oxidase (DAO) deficiency (this can be inherited or developed over time)
  • Histamine-rich foods

Foods that Contain or Trigger Histamine

In addition to the histamine produced inside your body, there are also a variety of foods that naturally contain histamine, cause the release of histamine, or block the enzyme that breaks down histamine, diamine oxidase.

Foods that Contain Histamine

  • Fermented alcoholic beverages: especially wine, champagne and beer
  • Cured meats: bacon, salami, pepperoni, luncheon meats and hot dogs
  • Soured foods: sour cream, sour milk, buttermilk, soured bread, etc.
  • Dried fruit: apricots, prunes, dates, figs, raisins
  • Fermented foods: sauerkraut, vinegar, soy sauce, kefir, yogurt, kombucha, etc.
  • Vinegar-containing foods: pickles, mayonnaise, olives
  • Most citrus fruits
  • Aged cheese including goat cheese
  • Nuts: walnuts, cashews, and peanuts
  • Vegetables: avocados, eggplant, spinach, and tomatoes
  • Smoked fish and certain species of fish: mackerel, mahi-mahi, tuna, anchovies, sardines

Foods that Cause the Release of Histamine

  • Alcohol
  • Bananas
  • Chocolate
  • Cow’s Milk
  • Nuts
  • Papaya
  • Pineapple
  • Shellfish
  • Strawberries
  • Tomatoes
  • Wheat Germ
  • Many artificial preservatives and dyes

Foods that Block DAO

  • Alcohol
  • Energy drinks
  • Black tea
  • Mate tea
  • Green tea

What can I eat?

You might be wondering now what you CAN eat, here is a list of low histamine foods as well. Remember that freshness is key when you have histamine intolerance!

Foods Naturally Low in Histamine

  • Freshly cooked meat, poultry (frozen or fresh)
  • Freshly caught fish
  • Eggs
  • Gluten-free grains: rice, quinoa
  • Pure peanut butter
  • Fresh fruits: mango, pear, watermelon, apple, kiwi, cantaloupe, grapes
  • Fresh vegetables (except tomatoes, spinach, avocado, and eggplant)
  • Dairy substitutes: coconut milk, rice milk, hemp milk, almond milk
  • Cooking oils: olive oil, coconut oil
  • Leafy herbs
  • Herbal teas

3 Ways to Naturally Regulate Histamine

  1. Elimination/Reintroduction  Remove the above high histamine foods for 30 days and reintroduce them one at a time.
  2. Blood Testing  There is a lab that can test for histamine levels and DAO levels. A high ratio of histamine/DAO signifies that you are ingesting too much histamine and that you don’t have enough DAO to break it down
  3. DAO Supplementation  If testing is unavailable to you, you could simply try a diet low in histamine and add DAO supplementation at each meal. If your symptoms resolve, you could have low DAO.

Recommended Supplement: Quercetin-Ascorbate

Important: Get to the Root Cause

Most importantly, find the root cause for the histamine intolerance. If you’re on a medication that is causing the intolerance, working with your physician to wean off of these medications is essential.

The main causes I see in my clinic are SIBO and gluten intolerance, which cause a leaky gut. In this case, I suggest healing the gut with a solid nutrition plan. Over time, you should be able to stop the DAO supplement and go back to eating histamine-containing foods.

If you’re currently suffering from histamine intolerance, you may not have to avoid these foods forever. It can be a short-term solution until your histamine or DAO levels return to their optimal ranges. Depending on your unique situation, you may find that you tolerate some foods better than others, so I encourage you to stay optimistic as you pay attention to your body!