When I was told about the histamine intolerance I suffered from, I didn’t believe it at first, I was afraid it was some bogus disease or some well we don’t know what’s wrong, so let’s just call it so and so. Just like former diagnosis I had gotten like irritable bowel syndrome and chronic fatigue syndrome.
But a histamine intolerance is a very real thing. And it’s quite clear what the cause of it is.
Histamine is an amino acid. A very small one even. One of the most well known functions of it is in the mediation of immunological responses. When harm is done to the body or intruders are noticed, histamine is released from specialized storage cells (mast cells) in the bloodstream to widen blood vessels and make their walls more permeable, so more blood and all handy things carried in the blood to fight of harm and intruders can go to the place of the disturbance.
Which is the reason a lot of the symptoms of histamine intolerance mimic allergic responses or real infections. Mimic, since it isn’t an allergic response or a reaction to a threat at all. Just a large amount of histamine can cause these responses.
The reason large amounts of histamine can build up in the body
There are several reasons a large amount of histamine can come into existence in the human body and lead to annoying responses.
Histamine is not just active in the human body. It is also present in most other animal life, and even in plants. Which means that most of our foods contain histamine. So we consume histamine with almost everything we eat and drink. There are also certain substances that are able to aggravate the mast cells in which histamine is stored, so their contents get released into the blood stream.
There are several enzymes that break down histamine. The main ones are histamine methyltransferase which mostly targets histamine within cells. And there is diamin oxidase (DAO) which is present in the walls of the bowels and within the bloodstream.
Most histamine intolerances are due to a lack of DAO. Ingested histamine is normally filtered within the walls of the bowels, so it doesn’t enter the bloodstream. And the histamine that has entered the bloodstream is filtered away with DAO as well. As the amount of DAO declines, the amount of free histamine in the body can grow rapidly, especially when foods high in histamine are eaten.
DOA can be low due to a genetic disorder. But the production of it can also be impaired when the bowels get damaged due to an infection but also different aggravations (antibiotics, crohn disease, gluten). A third reason the amount of DAO can be low is because it can be inactivated by several different substances, like certain medicines (morphine ) , but also alcohol impairs the working of it. Another reason a shortage of DAO can occur is when the components it is build out of aren’t present in large enough amounts, for example a shortage of copper and B6.
Since the levels of DAO can fluctuate with all these different reasons, the sensitivity to histamine can change depending on the circumstances. After a night of drinking I have to be much more careful with histamine rich foods. Stress can not only release histamine directly but also work against the working of DOA.
Since the response depends on the amount of histamine within the body, and this depends on it’s turn on the amount of DAO, the amount of histamine that can be taken before reactions occur is different for most people. And as most reactions only happen when a certain threshold is passed it will take a while for anyone to find out where that threshold is, and how certain things like stress affect this.
The amount of histamine in foods can also greatly vary, since the longer it is stored the more histamine is made by bacterial activity and other processes. That’s why certain foods like fish are okay if they are very fresh or never got defrosted. The same goes for any other food, like fruits and veggies.