Histamine: An organic nitrogenous compound involved in local immune responses, as well as regulating physiological function in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Histamine is involved in the inflammatory response and has a central role as a mediator of itching.

Diamine oxidase (DAO): A digestive enzyme produced in your kidneys, thymus and the intestinal lining of your digestive tract primarily responsible for breaking down excessive histamine in the body.

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   You may be surprised to hear that bananas, avocados and spinach are bad for your health in certain instances. For those with a histamine sensitivity or intolerance these foods are detrimental to their health. But before you start making any dietary changes, let's better understand the cause and approaches to manage or eliminate symptoms.
   A histamine sensitivity or intolerance can be likened to other food sensitivities or intolerances (allergies). You body's immune response is triggered as a result of surpassing a threshold level. If you allergic to a food this threshold is very low, not allowing any of the particular food to be consumed. To relate to this issue you can think of seasonal allergies. Allergens in the air (pollen, ragweed etc) trigger an immune response in the body causing histamine release and symptoms. Dietary choices also lead to this same histamine release in your body by one of two ways. First, certain foods are high histamine (HH) and increase the total amount of histamine in the body directly. Second, certain foods block the DAO enzyme that is responsible for breaking down histamine within the body, ultimately increasing the amount of histamine by lack of removal. Unfortunately, there are many commonly consumed foods and drinks that fall in one of these two categories.
   During times of elevated allergens, and subsequent histamine release, you may choose to take an anti-histamine medication. Those with a true intolerance or experiencing intense symptoms may not get the amount of relief needed. They can turn to dietary elimination and substitution to take a two-sided approach by not contributing to the issue (food choices) and managing the symptoms (anti-histamine medication or supplementation). The previously mentioned foods, and their roles in histamine levels, allow multiple ways to tailor your diet. It makes practical sense that you may want to lower both HH and DAO enzyme blocking food, or try to reduce the pairing of the two. The balance of eliminating one to allow another may be an early method to ease into this new diet strategy.

Basic principles of a low histamine (LH) diet:

• Elimination: Eliminate HH and DOA enzyme blocking foods
• Substitution: Substitute LH foods in place of HH to ensure meeting nutritional needs.
• Threshold: Identify your histamine threshold and reintroduce to personal preference.

Common HH foods:

• Bananas & citrus fruits
• Avocados
• Spinach
• Fermented foods (alcohol, sauerkraut, black tea)
• Nuts (peanuts, walnuts)

Common LH foods:

• Apples
• Whole grains (oats, rice)
• Carrots, asparagus, brocoli
• Fresh meats
• Olive oil

Building a LH diet: An expanded food list

Carbohydrates: Rice, quinoa, sweet potatoes, oats
Proteins: Chicken breast, turkey breast, ground bison, ground beef
Fats: Naturally occurring animal fats, olive oil, coconut oil
Vegetables: Carrots, brocoli, asparagus, beets
Fruits: Apples, peaches, blueberries

* A LH diet can appear to be fairly restrictive, but still allows a bit of personal preference. This is a fairly easy trade off for someone who does have a true histamine sensitivity or intolerance as the symptoms can be pretty intense. Making simple swaps (apples rather than bananas) can help keep you from exceeding your symptom threshold. Your level of sensitivity will likely determine your threshold and how much elimination is needed.

Who may benefit

   If congestion, GI distress, a recurring rash, headaches or excessive itching are common symptoms you face seasonally it may be worth looking at histamine sensitivity or intolerance. If pollen and other common allergies typically effect you strongly each year it is because those allergens trigger your body's histamine response. The most common therapy is an anti-histamine medication (Allegra, Zyrtec etc). For some this is not enough. If you fall in this category, try a two sided approach of managing the symptoms (medication and/or supplementation) and reducing nutritional contributors (HH & DAO blocking foods).

Special considerations

   If you do have a histamine sensitivity or intolerance, it's important to remember that you may still be sensitive to other foods. This can be a bit overwhelming as you need further restriction. By making simple changes at first, then progressing if necessary, you will likely be able to more accurately identify any problem food(s). For instance, you may be sensitive to dairy regardless of pasteurization or form, despite some forms of dairy being low histamine.

Practical approach

   Identify the most common, regularly consumed foods that need to be eliminated. For myself, I had a banana every morning and 1/2 an avocado every evening with my final meal. These two high histamine foods that were eaten every day were easy to identify and eliminate. HH foods were rarely an issue unless consumed in large amounts. However, during allergy season, I became very sensitive and developed allergic type reactions despite eating a very consistent, healthy diet. Taking into account I only experienced these symptoms certain months of the year (despite following a consistent diet year round) I took a look into a LH diet. My previous relief from anti-histamine medication and remission of symptoms in colder months provided more clarity.
   Once you've identified your threshold, you can include and exclude foods to meet your preferences for the day. Consuming alcohol can be mitigated by reducing or eliminating all other forms of HH or DAO foods during that same day (no caffeine, bananas or avocados that day for instance). If you are already following a healthy diet, you may find that with a little prep the LH diet is not that difficult to incorporate provided you know which foods are off limits. An overall easy diet to adapt to, it is worth considering if you have allergy type reactions that you cannot seem to manage effectively.

Sample meal(s):

1. 1/2 cup oats, apple, 1 tbsp. almond butter, cinnamon & honey
2. 5 oz. ground bison/turkey, 1/2 cup quinoa, 2 small beets, olive oil
3. 8 oz. chicken breast, 1/2 cup jasmine rice, mixed carrots, olive oil