A Tolerance Kitchen article.
The below content has been created with the input of a range of dietitians and sources. Following a low histamine diet should always be done alongside a qualified dietitian. Your own unique intolerances may make you more susceptible to certain foods than others, and long term adherence can lead to deficiencies in other important nutrients. You can find a list of trusted histamine dietitians here, all of whom offer 1:1 online sessions to help you get started and work with you to create a personalised diet.
When you're navigating the world of histamine intolerance, your freezer can feel like your greatest ally. It’s a common belief that freezing food resets its histamine content, making leftovers safe to eat days or weeks later. While this idea is appealing, it is unfortunately a myth.
The truth is that freezing is a pause button, not a rewind button. It’s an incredibly useful tool for managing the histamine in your diet, but only if you understand exactly what it does, and what it doesn’t do.
Understanding How Histamine Forms in Food
Before we can understand freezing, we need a quick reminder of how histamine appears in our food in the first place. Most fresh foods, like a just-caught fish for example, contain very little histamine.
Histamine is produced when bacteria convert an amino acid called histidine (which is naturally present in proteins) into histamine. The two key ingredients for this process are time and temperature. The longer a food sits at a temperature that bacteria enjoy (roughly between 5°C and 60°C, the food safety 'danger zone'), the more time these microbes have to produce histamine. You can read more about this in our guide to histamine in food and drink.
What Really Happens When You Freeze Food?
When you place food in the freezer, the cold temperature doesn't kill the bacteria. Instead, it puts them into a state of suspended animation. Their metabolic processes, including the conversion of histidine to histamine, grind to a halt.
Think of it like pausing a film. The story stops exactly where it is. It doesn't go backwards, and the characters don't reset. When you press play again (by defrosting the food), the story picks up right where it left off.
The same is true for histamine. The histamine that was already created by bacteria before the food was frozen remains completely intact. It is a very stable compound, so the freezing process does not break it down or remove it. You are simply locking in the level of histamine that was present at the moment of freezing.
The 'Freeze-Fresh' Protocol: A Practical Guide
This is where you can take control. Since freezing locks in the histamine level, the goal is to freeze food when its histamine content is at its absolute lowest. This means minimising the time between the food being fresh (or freshly cooked) and it being frozen solid.
Here is a simple, practical protocol to follow:
- Shop smart: Buy the freshest meat and fish you can find. Pay close attention to 'use by' dates, and check the packaging for 'frozen at sea' or 'individually quick frozen' (IQF) where appropriate
- Cool quickly: A classic British habit is to leave a Sunday roast or a large pot of casserole on the side to cool for hours. This is prime time for histamine production. Instead, decant hot food into smaller, shallower containers to increase the surface area and help it cool down much faster
- Fridge first, then freeze: Aim to get cooked food into the fridge within 90 minutes. Once it's cool, transfer it to the freezer immediately. Don't leave it in the fridge for a day or two before deciding to freeze it
- Freeze on day one: For fresh meat and fish, the best practice is to either cook and eat it on the day of purchase or portion and freeze it immediately. A chicken breast frozen on Monday will have far less histamine than the same chicken breast left in the fridge until Wednesday and then frozen
Defrosting: Don't Undo Your Hard Work
How you defrost your food is just as important as how you freeze it. Defrosting food on the kitchen counter is not a good idea. As the food's surface warms up, bacteria can 'wake up' and start producing histamine again, long before the centre of the food has even thawed.
The safest methods for defrosting are:
- In the fridge: This is the best method. It keeps the food below 5°C, out of the temperature danger zone, while it thaws slowly and safely
- In the microwave: Use the defrost setting on your microwave immediately before you plan to cook or reheat the food
Managing Your Histamine Bucket
Following this 'freeze-fresh' protocol helps you manage your personal histamine bucket. By ensuring the food you freeze and later eat is as low in histamine as possible, you are reducing the amount of external histamine your body has to deal with. This leaves more capacity in your bucket before it overflows.
While the freezer is a pause button rather than a rewind button, it is still a crucial tool at your disposal when it comes to managing histamine levels in food. In a previous article we explored why the freezer aisle might just be your best friend, and armed with the right knowledge and little bit of planning, you can make better decisions about your diet.
This article is for informational purposes only and does not constitute medical advice. Please consult a qualified healthcare professional for advice specific to your situation.