Since we are celebrating Easter, it has come to my mind that we are officially in Autumn! This leads me to my next frame of mind….allergy time. I am more than sure that you are thinking, ‘Histamine – PMS & Anxiety, what does one have to do with the other??’

Well, my friend A LOT.

This will be a bit of the ‘the egg, or the chicken’ scenario as histamine and oestrogen go hand in hand, along with gut health. These all have an impact on PMS and anxiety symptoms along with your nutrient status . 

So, I ask that you bear with me over the next few months while I try to make sense of this to you.


As most of you would be aware, histamine is a compound released by your mast cells to fight off ‘unwanted bodies/elements’, setting off an immune reaction. Your reaction will vary depending on how your body sees these foreign elements, causing inflammation – vasodilation, redness, heat and pain.

Histamine is also produced by the breakdown of histidine, an amino acid, in your stomach! The production of histamine also supports activation of hydrochloric acid and enzymes. Both of which are needed for secondary stages of digestion.

Histamine is then ‘deactivated’ in the intestines by DAO (Diamine Oxidase). DAO is another enzyme produced in the microvilli of the intestines – supported by other vitamins and minerals.

So by now I am sure you can now see, or guess, where gut health enters the picture. If you have inflammation within your intestinal system, the little microvilli will not be healthy – or there may be less available.

If you do not have healthy microvilli, then there is reduced DAO activity. Which then leads to increased levels of histamine causing allergic reactions. I will talk about symptoms and why a little further on.


Now you may also be asking, what do oestrogen and histamine have to do with each other? Well, these two are buddies. They each stimulate each other via mast cells, which are part of immune function. What this means, is oestrogen is binding to the mast cells – instead of histamine to support immune activity.  This then stimulates other histamine receptor sites to release more histamine

This connection is needed during ovulation, premenstrual phase. Histamine, when it is in balance, has a positive effect on your reproductive cycle. It stimulates blood flow to the uterus, stimulating oestrogen production. Furthermore, progesterone seems to have an ‘anti-inflammatory’ effect on histamine, by producing more DAO.

Which seems like a great thing, all chemicals in balance nothing in high levels. Right? Well, kind of, because you see, oestrogen also needs DAO to be broken down and eliminated from the body. But, luckily enough, histamine has another way to be cleared out of the body – one that is linked to production of neurotransmitters.

Oh, were you also aware that adipose tissue (your body fat) also produces oestrogen? So, if you have a little more than you should, this could only be adding  to your histamine-PMS & anxiety issues.


Again, you may be wondering how histamine affects PMS and anxiety? If you could be a little more patient with me, I will get you there. I just need to ‘lay the foundations’ before putting it all together.

So, the brain also has histamine receptors, which regulated your neurotransmitters noradrenaline and epinephrine. This is one of the hormones that works in response to stress and exercise, which your body needs in order to get your blood and heart pumping for energy.  It is also involved with focusing your mind and your sleep-wake cycle, amongst other things.

These neurotransmitters are released when you are in ‘fight or flight  mode priming your body with energy, helping you to focus your  body and mind on what is happening.  You break this down with the enzyme HNMT (Histamine N-methyltransferase).

Furthermore, GABA is also regulated by histamine, which has a calming effect on your brain.

What now?

I know that at the moment you cannot see a connection, but next month I’ll join the dots. I will talk about how these things interact when there is an imbalance due to inflammation. This can be due to nutrient deficiencies, changes in the DAO and HNMT genes and/or methylation.

There could be other issues, but these are the main ones that your may be faced with. Any one of these issues, or a combination of these things, will affect your body’s ability to clear out the excess histamine and oestrogen.

If you need more support and guidance with these issues, please book in to see me. I will be able to provide you with a treatment plan aimed at your personal presenting concerns.



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