Navigating and understanding Histamine intolerance
Aaaaaaaah histamine, you sneaky little devil. It is so interesting how themes and conditions really come and go in health. Back when I started studying Naturopathy in 2002, the only thing I remember being discussed in relation to histamine is its involvement in the acute inflammatory response. That is right, histamine is not all bad! It plays an especially important role in the body’s response to injury and infection, as well as its’ action as a neurotransmitter. Histamine’s main, basic function is to increase blood vessel permeability to allow the influx of immune mediators, to go to the site of the injury and start the healing process.
If we expand on that a little more, we know that receptors for histamine, or sites for histamine to act on, are located throughout the body. On smooth muscle and in our gut to name a few of the major sites of histamine activation. Histamine is responsible for the symptoms we typically associate with an allergy, injury or reaction and can vary from a very localised area such as when we get bitten (think small, red, inflamed, itchy bite) to an entirely systemic response as in the case of anaphylaxis. Both reactions involve histamine and cause a degree of itching, swelling, redness and inflammation. In the case of an exaggerated immune response such as seen in anaphylaxis, histamine is responsible for bronchial constriction, leading to difficulty breathing as histamine receptors are located on smooth muscle. We also know in the case of anaphylaxis that there are other significant contributors to the development of such reactions.
What is lesser known about histamine is that it is a neurotransmitter also. It has marked influence on the brain. Its actions influence our central nervous system and wakefulness. Histamine activity fires consistently during the day, then almost completely stops overnight, hence why older style Antihistamines have a sedating effect. It is believed that this decrease in histamine during sleep enables REM sleep when we restore and repair. So, we can start to understand the far-reaching consequences of poorly managed histamine regulation on mood, energy, inflammation and hormone balance.
There are two main pathways responsible for the down-regulation of histamine. When we ingest histamines, found naturally in some foods, or we release histamine in response to injury or reaction, the body usually has two very reliable means to metabolise histamine and get levels back to normal. The first is by a process involving methylation. The body donates a chemical compound called a “methyl group” which is tacked onto histamine, changing its structure and thus, it’s action, allowing the compound to be broken down and excreted. This process relies heavily on the body having healthy and uncompromised methylation pathways and abilities. There are some genetic mutations such as MTHFR that may compromise these pathways. A compound called Sam e (S-Adenosine-L-Methionine) is crucial for this process.
The other significant player in the downregulation of histamine is an enzyme called DAO, which is primarily produced in the lining of our small intestinal tract. It is also produced in large quantities in the placenta during pregnancy, which may explain why women experience significantly improved food tolerance and reduced allergic symptoms while pregnant. For example, many report being able to tolerate dairy, where they previously have not been able to. Now that we understand more about DAO, we can also start to theorise WHY histamine intolerance is beginning to become such an issue for so many. There has been much discussion and research into “leaky gut” in recent years, for those that need a refresher, here is the nutshell version.
When we refer the “the gut”, typically this is in reference to our small intestine, the site of so much nutrient absorption and enzyme production. The mucous membrane lining of a healthy gut should be permeable enough for nutrients to pass through the wall into the bloodstream for uptake and assimilation, but small enough to keep out larger compounds such as food particles etc. from entering the bloodstream and stimulating an immune response to the “foreign invader”. (food is not supposed to end up in our bloodstream!)
Due to SO many factors such as medications, antibiotics, poor diet, stress and microbial imbalance, this fragile intestinal wall becomes compromised, inflamed and ultimately damaged and penetrated. The metaphorical tight drum slowly become a leaky sieve, hence the term “leaky gut”. So, back to my point……. If this lining is compromised, this has the capacity to severely impacts the body’s ability to adequately produce the DAO enzyme for histamine regulation, and we then begin to see the effects of histamine overload……
We also recognise a very strong relationship between estrogen and histamine. In short, without getting too far down the rabbit hole, histamine and estrogen tend to follow each other…. Estrogen receptors have been located on mast cells. Mast cells essentially trigger the release of histamine. Thus, at times of the cycle where estrogen is at its peak, such as at ovulation, as well as its relative dominance seen premenstrually, we can also see symptoms of histamine overload such as ovulation pain, migraine/headache, irregular bowels, mood changes, increase in symptoms associated with asthma, skin conditions, sinus congestion and hay fever, to name a few. We also know that progesterone INHIBITS histamine. So, in the few days BEFORE your period starts, there is a sharp decrease in progesterone to stimulate the release of the endometrial lining to cause a bleed (your period) this leaves increased levels of estrogen essentially unopposed and free to create histamine havoc……
I completely appreciate how overwhelming this all must feel, but equally interesting and mind-blowing!
When we begin to understand to origins of dysfunction, we begin to see the way out.
The clinical approach to improving and managing Histamine intolerance is incredibly complex. Unfortunately, there is not a 1 test diagnosis. It is normally a diagnosis based on symptoms. Congestion increase in allergic reactions and responses, wheezing, increased headache and migraine, flaring of skin symptoms, mood changes and gut dysfunction to highlight a few. The core treatment considerations are identifying the main cause of histamine production (bad bacteria in the gut, estrogen metabolism, nutrient deficiency, inflammation etc.) as well as temporarily reducing foods high in histamines. These are typically fermented and aged foods. Think sauerkraut, kefir, mainstream broad-spectrum probiotics (they can release their own histamine) kombucha, aged cheese, bone broth and slow-cooked meats, alcohol, pickled foods, smoked foods, certain fruit and vegetables such as tomatoes, avocado, spinach and oranges, fish that isn’t fresh…..
My advice for those that feel histamine intolerance may be an issue for you is to take note of your symptoms. For women, track where in your cycle they occur. Keep a diet and symptom diary. But most of all, speak to someone who can help you unravel the layers and piece together YOUR jigsaw.
Keep an eye out for my Histamine intolerance recipe book and meal plans coming soon.