When I mention histamine reactions, most people think of runny noses, itchy eyes and skin rashes – and whilst this is a certainly a large component of histamine reactions, this is not the full story. Common symptoms of a dietary histamine reaction also includes migraines, headaches, dizziness, heart palpitations, anxiety, flushing, diarrhoea, nausea and indigestion to name just a few.

In healthy individuals, histamine is broken down on a regular basis by two enzymes: DAO and HNMT. DAO is produced in the intestine, so if the intestinal function is compromised there may not be enough DAO to degrade histamine normally resulting in digestive symptoms such as loose stools and diarrhoea.

If histamine is not being broken down effectively in the body, it can also act as an excitatory neurotransmitter, worsening feelings of anxiety and agitation. A common food histamine reaction will be heart palpitations or racing heart after consuming a high-histamine food such as wine, aged cheeses or chocolate.

If you suspect you may be experiencing a histamine reaction, try to avoid the “high histamine” foods as much as possible and minimise the “histamine-releasing” foods and see if your symptoms reduce. You may notice you will be able to tolerate small amounts in your diet without getting symptoms as everyone has different tolerance levels, so the idea is to establish your threshold level, with the aim of gradually improving it over time.

High histamine levels are also linked with the MTHFR gene mutation as balanced methylation helps degrade histamine. Thus to reduce your histamine reactions, you may need to work on your methylation and folate status in combination with implementing a low-histamine diet.

As a general guide, the highest histamine foods are aged and fermented foods such as wine, beer, aged cheeses, vinegars, smoked meats/fish and artificial additives such as sulphites and nitrites. See below:

Low histamine foods – eat freely:

Fresh cooked meat, fish or chicken (days old left-over meat not ideal as histamine content increases)
Any fresh vegetables (with the exception of tomatoes)
Any fresh fruit (with the exception of strawberries and citrus fruit (lemon in water is ok)
Grains (rice, quinoa, rice noodles)
Eggs
Seeds & Nuts (except for peanuts and sometimes walnuts)
Milk substitues – coconut milk, rice milk, almond milk
Cooking oils – coconut oil & olive oil
Herbal teas – with the exception of green tea

High histamine foods – reduce consumption: