HI RacJen et al.
I have been researching histamine intolerance and mast cell activation for a while now as I have the former and probably have the latter.
It's a complicated subject with much conflicting information however there is a way through it all. Hopefully, the information below might help. Please recognise that I have put this together from my own research and am not a doctor or making recommendations.
1. What is it? Histamine intolerance is the inability to clear histamine in the gut often due to a deficiency of Diamine Oxidase (DAO) or problems with N-Methylhistamine. The general idea seems to be that you have a "histamine bucket" which fills up over time as your ability to clear histamine is less than the histamine present in the gut. After a while the bucket is full and overflows and hey presto! The symptoms are broad ranging and not just in the gut. The important point here is that you can be happily eating the same meal for several days and then suddenly you will react to the meal... you're not allergic to it but your body has had enough histamine to cause problems. This is partly why lots of people struggle to find the things that "trigger" them and of course everyone is different so it's hard to make direct comparisons between people. Mast Cell Activation Syndrome occurs when the mast cells become confused and release mediators "willy nilly" and some mast cell activation can be as a result of chronic histamine intolerance, some can be genetic. If you have histamine intolerance you won't necessarily have Mast Cell Activation. If you have Mast Cell Activation, you are quite likely to have histamine intolerance. Essentially I was told, work on the histamine intolerance and deal with that.
2. First Steps. The diet. Everywhere I looked the first thing to do was to adopt a 2 week low histamine diet. After the 2 weeks you would hopefully notice a difference and then you would be able to add back foods SLOWLY and one at a time, noting any reactions. There is no such thing as a "No histamine diet". Also it is important to recognise that histamine is present in some foods, some foods can liberate or provoke histamine production or can block the production of DAO. Not only that, but histamine can increase depending upon how food is cooked and prepared. It is really important not to eat leftovers even from the fridge and if you do cook more than you need, freeze it quickly. The SIGHI food list is widely recognised as the food list to use (there's a link below).
3. Antihistamines. These are a God send for me. Taking both H1 and H2 anti histamines on a daily basis doesn't reduce the amount of histamine circulating in the body but it does stop or reduce the symptoms. Dr Tina Peers recommends Fexofenadine 180mg twice per day as the H1 element and Famotidine as the H2 element. It should be noted that the standard dose of Fexofenadine is 180mg per day and so this would need to be under the guidance of a doctor. I have tried Levocertirizine but then changed to Fexofenadine and personally the latter gives me better results.
3. Supplements. Well, I understand that Vitamin C is a helpful supplement but it is better to take it through the day unless you have a sustained release version. I am currently taking 1000mg sustained release once per day.
Quercetin can also be quite helpful and I take 500mg once per day. DAOSIN or Diamine Oxidase capsules are also great but they're prohibitively expensive so I bought some to test and they made a difference, now I keep a few in case I eat out or can't control the dietary intake.
4. Hormones. Oestrogen and histamine increase each other. Almost like a "feedback loop" when oestrogen increases, so does histamine, but then when histamine increases, it prompts oestrogen to increase further and so on. This causes a lot of problems for women who cannot stabiliise their HRT dosage (just like me). It has been like a very unpleasant roller coaster for years now and I know from my own experience that the symptoms can be debilitating.
There are a number of papers published highlighting the fact that progesterone inhibits histamine production.
5. So, if you've made it this far, here are some of the links and reading which I have found useful. If you would like to talk further on my experiences on this journey, you're welcome to message me directly.
https://www.histaminintoleranz.ch/downloads/SIGHI-Leaflet_HistamineEliminationDiet.pdfhttps://www.mastzellaktivierung.info/downloads/foodlist/21_FoodList_EN_alphabetic_withCateg.pdfhttps://www.histamineintolerance.org.uk/https://www.drtinapeers.com/https://www.youtube.com/watch?v=em-BxpImE6Ahttps://lizearlewellbeing.com/histamine-intolerance-with-dr-tina-peers/