Allergies? You Could Have a Histamine-Intolerance (Plus a MTHFR Link)

Allergies? You could have a Histamine-Intolerance (Plus its connection to MTHFR) - janny: organically.

Many of you know I started skin brushing last year and that seemed to help me from many of my allergy outbreaks (in addition to air purifiers) but recently I noticed that I'll have the occasional day of unexplained sneezing and sinus flare-up which is gone the next day without intervention. I have been baffled, until now. 

If you suffer from allergies (seasonal, food, animal, etc.) there is a chance you may actually have a histamine intolerance. As I began writing this article on the final day of The Masters Tournament, the announcers were discussing the fact that Justin Rose (who tied for second!) is on low-histamine diet since his allergies have been a major problem for him. I have never heard about histamine in food until this week, and now I can't seem to get away from it!

Those who have a MTHFR gene mutation are likely candidates for histamine intolerance because the mutation inhibits our ability to methylate properly, a process by which many toxins, including excess histamine, is eliminated. 

I have known about my MTHFR gene mutation for a couple years, but since the studies are so new, much of the information is confusing and incomplete. So without going into too much detail, this is certain: 50% of the population suffers some combination of MTHFR, so it may be worth getting tested for. More on this a bit later.

What is histamine?

Histamine is a compound that is released by cells in response to injury and in allergic and inflammatory reactions, causing contraction of smooth muscle and dilation of capillaries.

Histamine is a Neurotransmitter, which means it delivers messages to the body from the brain when there is a potential allergen, causing swelling the blood vessels in search of the danger. This is an inflammatory response, causing a "swollen" feeling to your sinus, head or throat. This is a natural response, however, some people do not break down histamine effectively, so our bodies carry an excess of histamine resulting in ongoing symptoms of allergies. 

As long as we carry an excess amount of histamine, our bodies will remain in constant state of inflammation. 

Symptoms of Excess Histamine

  • Congestion
  • Runny nose
  • Sneezing
  • Itchy skin, eyes, nose
  • Hives
  • Throat swelling
  • Increased heart rate
  • Eczema
  • Headaches
  • Sleep issues (difficulty falling and staying asleep)
  • Anxiety
  • Fatigue
  • Cramping during ovulation and periods
  • Digestive problems
  • Nausea

Since histamine travels through our blood, if not broken down properly, it can effect most areas of our body, which is why it can affect more areas than just your sinus or throat. 

People with the MTHFR gene mutation suffer in many areas, including the inability to detoxify the body effectively. Depending on which gene mutation you have, you could be operating anywhere from 20-70% effectiveness. I am homozygous C677T, which means my body is only working at a 20-30% effective rate of detoxifying itself from many toxins, including excessive histamine!

Histamine in the nervous system is broken down by histamine N-methyltransferase (HNMT) while diamine oxidase (DAO) breaks down histamine in your digestive tract. Histamine may not be breaking down effectively due to deficiency in HNMT and/or DAO, though DAO takes most of the heat for being the responsible party for histamine-intolerance.

HNMT deficiency is related to a methylation process and DAO deficiency seems to be hereditary. Since we know that methylation issues (MTHFR) are hereditary as well, (you get a copy of DNA from each of your parents) it would seem both deficiencies are genetic conditions.


Histamine can also fluctuate with hormone levels, particularly estrogen, causing PMS symptoms (headache, fatigue and cramping) during specific phases of the menstrual cycle. Interestingly, when pregnant, the placenta produces an abundance of DAO, so in many cases, histamine-intolerant women experience relief during pregnancy!

Histamine in Food

Even though food not the problem, its important to know which foods to limit until we can help our bodies break down histamine properly. Eating these foods (especially in excess) to our diet will only continue to inflame our overwhelmed systems.

High Histamine Foods

  • Cheese (Aged and Fermented including goat cheese)
  • Cured meats (bacon, salami, pepperoni, deli meat, hot dogs)
  • Fermented alcohol (particularly wine, beer and champagne)
  • Fermented foods (sauerkraut, vinegar, soy sauce, kefir, yogurt, kombucha)
  • Fish (Mackerel, mahi-mahi, tuna, anchovies, sardines)
  • Fish (Smoked)
  • Fruit (Most Citrus and also Dried including popular ones like raisins, dates, figs, apricots, prunes)
  • Nuts (walnuts, cashews and peanuts)
  • Seasonings (Cinnamon, cloves, chilli powder, anise, curry powder, nutmeg)
  • Soured foods (sour cream, sour milk, buttermilk, soured bread)
  • Vegetables (avocado, eggplant, spinach, tomatoes)
  • Vinegar-containing foods (pickles, mayonnaise, olives)

Histamine-Releasing Food

  • Alcohol
  • Artificial dyes and preservatives
  • Bananas
  • Chocolate
  • Cow's Milk
  • Leftover Meat and Fish
  • Nuts
  • Papaya
  • Pineapple
  • Shellfish
  • Strawberries
  • Tomatoes
  • Wheat Germ

DAO-Blocking Foods

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

Source: Mind Body Green and Healthy Pixels

Those suffering from autoimmune diseases, endocrine disorders and gut-related issues are often told to consume fermented foods regularly, however, this is one of the high histamine foods! Oh the dilemma!

I have a mild intolerance to kale, so I eat a lot more spinach, but that is also high! I guess I have to stick with Romaine. I don't know that anyone can peel me away from my cashew milk though. You can pry it out of my cold, swollen, histamine-filled hands.

Well what about some good news for a moment:

Low Histamine Foods

  • Cooking oils (olive oil, coconut oil)
  • Dairy substitutes (coconut milk, rice milk, almond milk) make these yourself or make sure they do not contain icky ingredients like carrageenan!
  • Eggs
  • Freshly cooked meat, poultry (frozen or fresh)
  • Freshly caught fish
  • Fresh Fruits (mango, pear, watermelon, apple, kiwi, cantaloupe, grapes)
  • Fresh Vegetables (except tomatoes, spinach, avocado and eggplant)
  • Gluten-free grains (rice, quinoa)
  • Leafy Herbs and Herbal tea
  • Pure Peanut Butter and Almond Butter

Source: Mind Body Green

Histamine and Medications

I'd be remiss if I didn't mention this finding:

Some medications can release histamine; others can reduce the effectiveness of the enzyme (diamine oxidase) that breaks down histamine. As a result, the level of histamine rises and may cause symptoms, even in a person who has shown no signs of histamine intolerance in the past. Common pain killers such as aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), some diuretics (“water pills”), antibiotics, and antidepressants are among the medications that can affect the functioning of DAO. A list of medications that either release histamine, or decrease the effectiveness of DAO can be found in Maintz L, Novak N. Histamine and histamine intolerance. Am J Clin Nutr 2007;85:1185-1196


What shall we do? 

  • Low Histamine Diet
    • Try removing some, most, all of the high histamine foods from your diet and see what happens!
  • DAO Supplements
    • You may be DAO deficient. HistDAO by Xymogen is a recommended supplement that I'm eyeing. I'll do more research and testing in the coming months. If anyone has tried this or another supplement, please share your findings! Update - I see this product is no longer available from amazon though it can be purchased directly from the brand. 
    • I've read a few research studies showing how DAO naturally occurs in pea and legume sprouts and if you grow them yourself (in the dark) the DAO content is higher than commercially sold sprouts. (Read more here). I just bought some to grow on my own to add to smoothies!
  • Blood Work
    • DAO Deficiency?
    • Histamine to DAO ratio?
    • MTHFR Mutation?
    • It may be critical to find out if you have a DAO deficiency, or unbalanced Histamine to DAO ratio and/or a mutated methylation gene (MTHFR). While allergies can be quite annoying and sometimes debilitating, MTHFR mutations can play a huge role in diseases and disorders ranging from High Blood Pressure, Endocrine disorders, Autism, Autoimmune and pretty much everything in between. I am seeking a genetic specialist to discuss this in greater detail because the majority of doctors do not know much about MTHFR, and if they have heard of it, they tend to brush it off simply because they don't know enough. The first step is getting tested, then go from there. 
  • Try to Stay Away From the Meds 
    • Antihistamines like Benedryl, Zyrtec and Allegra, while providing immediate relief, will deplete your body of DAO and in turn make you reliant on them.

Obviously, this is new and incredible information to me. I normally wait to post topics like this until I have some first hand experience to share, but history has shown me this could take years to do on my own. I have recently met a number of people with MTHFR, so the more information we are sharing, the better!