Chronic stuffy nose? Unexplained eczema? Puffy eyes? Migraines? These can all be symptoms of an allergy, but if the allergen is tough to pinpoint, it might be a histamine intolerance.
What are Histamines?
Histamines are a naturally occurring compounds that help your body regulate specific functions, including your digestive, nervous, and immune systems. Most likely, you have heard the term histamine in reference to an allergic reaction. When you have an allergy, the body releases histamines when the allergen is present. Mild histamine-induced symptoms include nasal congestion, sneezing, rashes and itchy skin, headaches, and sneezing. More severe symptoms can include migraines, nausea, vomiting, diarrhea, digestive distress, irregular heartbeat, and low blood pressure.
Not only are histamines produced in the body, they can also be ingested in certain foods, particularly those that are aged and fermented like cheese, wine, beer, pickles, smoked meat and fish, and vinegar. All the good stuff! You may have a histamine intolerance when an elevated histamine level is not linked to one specific food or allergen and does not cause an immune cell reaction. With a histamine intolerance, it can sometimes be hard to pinpoint which food or group of foods give you symptoms.
Low Histamine Foods
Foods with naturally occurring low levels of histamine should be favored if an intolerance is suspected. These include:
• fresh meat and fish
• most fresh vegetables — except spinach, tomatoes, avocado, and eggplant
• most fresh fruit — except citrus and some berries
• oils like coconut and olive oil
• grains, including rice, quinoa, corn, teff, and millet
High Histamine Foods
If you suspect and intolerance, you may want to reduce or avoid foods with high levels of histamine such as:
• alcoholic beverages, such as beer, wine, and liquor
• fermented foods, such as sauerkraut, pickles, yogurt, and kimchi
• aged foods, such as cheeses and smoked and cured meats
• nuts, such as peanuts and cashews
• certain fruits, including citrus fruits, bananas, papaya, and strawberries
• certain vegetables, including tomatoes, spinach, eggplant, and avocado
• certain food additives, colorings, and preservatives
Diamine Oxidase (DAO) and Histamine Intolerance
Another suspected cause of histamine intolerance is a diamine oxidase (DAO) deficiency. If histamine levels are too high, an enzyme known as diamine oxidase (DAO) breaks down the excess and can relieve some of your allergy-like symptoms. DAO is produced by the body in the kidneys, thymus and lining of the digestive tract, and works to regulate histamine levels to keep them within a healthy range.
When DAO is low, the body cannot breakdown excess histamine and symptoms persist. Factors that may contribute to high levels of histamine are genetic predisposition, excess alcohol consumption, medication, small intestine bacterial overgrowth (SIBO), and eating large amounts of histamine-containing and inducing foods.
Treatment of Histamine Intolerance
Because the research behind this condition is ongoing and not decisive, there is no gold standard diagnosis or treatment for histamine intolerance. The best option is to check with your healthcare professional to rule out allergens and check for DAO deficiency.
A dietitian can assist with an elimination diet to help identify foods contributing to high levels of histamine and recommend a dietary treatment plan of low histamine foods. Nutritional therapy designed to improve histamine tolerance and DAO function will also include adequate intake of nutrients that are involved in breaking down histamine, including copper and vitamins B6 and C. Some research also suggests that an adequate intake of healthy fats and other nutrients — like phosphorus, zinc, magnesium, iron, and vitamin B12 — may play a role in enhancing DAO activity.
DAO supplements are also available as over-the-counter products that restore the diamine oxidase enzyme in your body. They help break down histamine-rich foods and may reduce symptoms of histamine intolerance. There has been some research showing that these supplements might offer relief from headaches, digestive issues, and skin reactions. While these studies show positive results, more research is needed to understand how DAO supplements work and if they can help reduce symptoms of histamine intolerance in most people. In addition, since there is not a test to diagnose histamine intolerance, taking a DAO supplement if you don’t need it, could unnecessarily lower your histamine levels. Also of note, DAO supplements are produced from pork kidneys and may not align with individual dietary and religious dietary restrictions. DAO supplements are also pricey at $60-$70 for 60 capsules.
If you are experiencing symptoms of histamine intolerance, you should consult a qualified healthcare provider before diagnosing yourself. If you have histamine intolerance, the guidance of a dietitian can help you prepare a plan that addresses food sensitivities while avoiding nutrient deficiencies from an overly limited diet. While DAO supplementation may prove helpful, you may find that dietary changes effectively address the root cause, a strategy that may ultimately be more effective and far less costly.
Karen Kruza, MPH, RD is a Registered Dietitian Nutritionist specializing in weight and type 2 diabetes management at http://www.kruzanutrition.com.