Histamine Intolerance

Histamine Intolerance is another illness that has some of the same symptoms of a Mast Cell Activation Disorder (MCAD).  Those with Histamine Intolerance have only an excess of histamine in their body.  Their mast cells works appropriately and as such the other compounds released by mast cells are at the appropriate levels.

As I have mentioned previously, there are two enzymes that break down histamine in the body DAO and HNMT.  Those with histamine intolerance have a lower than normal activity of one or both of these enzymes, although most research is focused on DAO. Their histamine buckets, therefore, are markedly smaller than normal and as such regularly overflow.  These histamine intolerant people then present with many characteristics of a mast cell disorder.

HNMT is responsible for degrading histamine within a cell.  DAO is responsible for degrading histamine outside of cells and is they key enzyme in the digestive system responsible to degrade ingested histamine. DAO is susceptible to things like an unhealthy bacterial flora or an injured digestive system.  Various drugs like alcohol, opiods and certain medications can also inhibit DAO.  The first thing suggested to a person with a low DAO activity is to stop ingesting things that inhibit DAO and to treat any injury to the digestive system. This might include taking medication to kill injurious organisms within the digestive system and replacing those organisms with healthy ones.  Doing so might then raise the levels of DAO to appropriate levels.  However, if the activity of DAO is low due to a genetic defect, this alone will not provide relief.

The next step would then be to limit the amount of ingested histamine.  Fermented, aged, very ripe and left over food are all very high in histamine and hence would be eliminated from the diet.  Elimination of other high histamine food, like the ones noted by Dr. Janice Joneja, should also bring quick relief.  It is important to note, however, that naturally high histamine food is also quite good for you.  The best scenario would then be to limit the fermented, aged, very ripe and left over food and tolerate as much of the good for you food that you can (so pass on the sausage and instead eat a banana).

Some people also take supplements containing DAO when they eat but this does not always provide relief. The correct dosage of such supplementation and whether supplemented enzyme is active in the digestive system is not currently known.

If your histamine related symptoms are closely related to food consumption it is likely that you have histamine intolerance and not a mast cell activation disorder.  Limiting ingested histamine might then bring significant relief of your symptoms.

Additionally, pursuing treatment for seasonal and environmental allergies will also help.  Doing so will decrease the amount of histamine that your body is producing and empty your histamine bucket significantly. You then might find that you can tolerate ingesting higher histamine food with less problems.

If you would like to read more about histamine intolerance, check out the article Histamine and Histamine Intolerance from The American  Journal of Clinical Nutrition.

For those with MCADs, limiting ingested histamine can be helpful but often is not sufficient to provide significant relief.  A high nutrient, anti inflammatory diet is a much better fit as long as it can be tolerated.

What is all this about a Histamine Bucket?

People generally only think about histamine when they have an allergic reaction or seasonal allergies.  However, histamine has numerous other roles in the body.  Histamine is sent to a receptor in your stomach, for example, when you think about or eat food.  Your stomach then releases acid and other digestive enzymes to begin significant digestion of that food.  In fact, there are at least four different histamine receptors throughout your body.  Histamine is critical to many biological pathways and therefore necessary for typical bodily functions.  Without histamine, you would not be alive.

Many living things produce histamine.  Plants have varying levels of histamine present at different points of maturity and the more ripe the edible portion of a plant is the more histamine is likely to be present.  Some of this is due to the work of bacteria present inside and all over all just about everything.  Food which is intentionally aged or fermented in anyway is therefore high in histamine content.  Additionally there are histamine producing organisms living in your digestive system helping to digest what you have consumed.

The histamine present in your body then is related to how much histamine it has made, how much histamine the organisms in the digestive track have made and how much histamine was consumed.

Since the body makes and consumes histamine, it also produces two enzymes which degrade histamine: DAO (formerly known as histaminase) and histamine-N-methyltransferase (HNMT).  DAO is found in only particular areas of the body while HNMT is widely expressed in human tissues.  When these enzymes encounter histamine they degrade it.  Enzymes are finely tuned biological molecules.  Since there always has to be a baseline amount of histamine present for normal bodily function, DAO and HNMT are never supposed to totally eliminate histamine's presence in your body.

Now, consider your body's ability to degrade histamine to be represented as a bucket.  Inside that bucket is the amount of histamine in your body that has not yet been degraded.  The bucket can be mostly empty or mostly full but you feel the same - totally fine.  Histamine is doing what it is supposed to be doing in your body and you have not surpassed the capacity of the bucket.

What can make your bucket overflow?

- An allergic reaction.

- Consuming large quantities of histamine in your diet

- Producing more histamine than is needed for general bodily function

- Not having appropriate DAO and/or HNMT activity in your body

The crazy thing about this is that your histamine bucket can be rather large or rather small depending on the activity of DAO and HNMT at a given time.  Additionally, the histamine present comes from multiple sources and is additive.  So your bucket might be quite full on one day because you made a lot of histamine and ingested a lot of histamine.  It is likely on that day nearly anything else will cause your bucket to overflow.  On another day, you made very little histamine and ate very little histamine.  It would then take a much larger amount of histamine to cause your bucket to overflow.

Since I was ten years old I have often described my body as being in "freak out mode" for days, months and even years.  For some reason, my body's "histamine bucket" is often overflowing.

My next post will deal with what might cause you to make more histamine and what might decrease your body's ability to degrade histamine.