Someone obviously very new to the world of histamine in foods asked a question on my blog recently and it took me right back to when I was first really ill and totally confused and bewildered about the whole subject. I’d barely heard of Histamine Intolerance when I was diagnosed and little of what I read online made sense. All the low histamine food lists differed from one another and no-one seemed to be able to tell me exactly what to do or what to eat to get myself better. So I thought I’d do a post of the questions I had 5 years ago in the hopes it helps my readers new to the world of histamine intolerance. Bear in mind this is just my personal opinion based on my experience and research which I have read – I am not the Oracle of all things histamine and just a (still) bewildered patient alongside the rest of you.
Q. Why are all the lists different? Why are some more strict than others?
A. All the low histamine food lists online are based mostly on the personal opinion of the Author. No spice, food preservative, food additive, citrus fruit, chocolate, tea leaf, herb or much of anything else has been tested for its histamine content. In fact, only a handful of foods (mainly fish, soya, sauerkraut, aubergiene/eggplant, dairy) have been tested for their histamine content, so the lists are mostly pure speculation. I know that’s not what you want to hear, but it’s true.
Q. Is pak choi/vodka/lentils/bagels/insert-your-food-of-choice-here high in histamine?
A. I have no clue and neither does anyone else. That’s because it hasn’t been tested for its histamine content. Even foods thought to be high in histamine, eg. cheddar cheese, will differ depending on how it was produced, stored or transported. A certain brand of cheddar cheese in Italy may test lower, or higher, than another brand of cheddar cheese in America.
Q. So which low histamine food list should I use?!
A. It’s entirely your personal choice. None of them are THE definitive food list because that doesn’t exist. My advice would be to choose a list you think you can stick to, give a go for 4-6 months and see if it helps.
Q. Does the cooking method affect the food’s histamine content?
A. There was a recent study showing that frying and grilling specific types of food increased its histamine content, whereas boiling sometimes decreased it. However, it depended on the type of food. Eggs, for example, showed little rise or fall in histamine regardless of how they were cooked but fried vegetables had more histamine than raw vegetables. As with all things histamine it’s not as simple as fry or don’t fry, boil or don’t boil. It’s not something I personally worry about.
Q. Why can’t I eat leftovers?
A. It’s the freshness of food which affects its histamine content. The older the food, the more histamine it has. So 2 day old leftovers are going to be higher in histamine than fresh food cooked and eaten on the day it’s bought. At least that’s the theory, but again it’s not that simple. Who knows whether “fresh” unripe bananas picked in the Caribbean, taken on an open truck in forty degree heat to a warehouse, sorted, repacked onto another truck to go to the docks, travel in an unfridgerated container for a week to reach England, put on another truck to a warehouse, then forwarded to Tescos in Preston, then packed in the boot of your car for an hour as you drive home, then sat in a fruit bowl for three days before you eat them are going to be lower in histamine than chicken soup you made yourself yesterday but have reheated?!
Q. Does refrigeration affect histamine levels?
A. Most of the research on this has been done on fish. Little is known of the effect refrigeration has on eggs or carrots for example. However, from the limited research refrigeration slows down histamine formation. But if the food already contains histamine, eg the banana example above, it won’t reduce it.
Q. Does freezing affect histamine levels?
A. Freezing is the only thing which halts histamine formation. However, it doesn’t destroy histamine which has already formed. So if you freeze a week old uncooked chicken breast which already contains high levels of histamine the histamine will still be there. My advice would be to freeze foods as soon as you buy them or freeze meals as soon as you’ve cooked them, then cook from frozen whenever possible or at least cook or eat as soon as they’ve defrosted. I never defrost stuff for hours overnight in the fridge, preferring to defrost at room temp for 1-3 hours then cook and eat.
Q. What about histamine levels of canned foods?
A. As far as I’m aware no tinned goods have been tested for their histamine content and in any event it would probably depend on the type of food and how it had been stored and prepared prior to canning. I guess tinned goods are on the ‘excluded’ lists of low histamine diets because they contain preservatives (which haven’t been tested for histamine either!) and because they’re considered ‘old’ and assumed to be high in histamine, but it is just an assumption. The truth is no-one knows. I eat tinned beans and don’t react to them in any way, but that’s just me.
Q. What about dried goods, eg. pasta.
A. Again, they haven’t been tested for their histamine content so no-one knows.
Q. What’s the deal with histamine liberators?
A. Histamine liberators are irrelevant in histamine intolerance as HIT involves DAO and HNMT not mast cell activation per se. However, I know many people with mast cell disease also follow a low histamine diet, which is why I’ve included this question. There is no such thing as a histamine liberating food as far as we know. No research has been conducted that shows any particular food liberates histamine stored in mast cells. This includes egg whites and stawberries. Which doesn’t mean to say you don’t have a reaction to a food, but that it’s your immune system which is over-reacting to a harmless substance and nothing intrinsic in the food itself which causes a reaction. I react badly to apples, for example, because I have a birch pollen allergy and they are related – it doesn’t mean apples are histamine liberators. I take no notice whatsoever of information online which tells me some food or other is a “histamine liberator” and will continue to do so unless it’s proved otherwise through research.
I’m sure you’re now thinking “well what the hell do I eat and how can I know it’s low in histamine?!”. The fact is the whole low histamine food area is a very very complex subject with so many variables it makes your head spin. There is no easy “eat this and don’t eat that” solution, I wish there were. The histamine content of any particular food depends on so many things including its age and the way it’s been picked, handled, transported, processed and stored. It will differ from food to food. A button mushroom in China may differ in its histamine content compared to a button mushroom in Wales. Strawberries picked out of your garden will differ from strawberries imported from Israel. And so on ad nauseum.
Nearly every article online about HIT refers to the same single research paper. However, the paper is fundamentally flawed as explained in my Histamine in foods: the evidence page. For example, it lists egg whites as a histamine liberator based on a worthless solitary study of animals in 1956 which was never published or replicated let alone tested on human beings. Yet this has gone viral and now everyone treats it as fact when it is anything but. The truth is the research evidence on the histamine content of food is poor and much of it is decades old – there were no refridgerated lorries in the 1950s. In fact there were hardly any fridges in the 1950s. We have come a long way in the last 70 years in how we pick, transport and store food which is why research needs to be up-to-date.
However, there is hope on the horizon. A home testing kit is being developed in Germany which will enable us to precisely measure histamine in food. This is the only way we will know for sure how much histamine is in the actual food we’re eating and it can’t come soon enough.