Histamine is a compound which acts as a hormone for the immune system and as a neurotransmitter for the central nervous system. It’s a localised mediator of inflammatory responses, initiating symptoms like itching.
As a neurotransmitter, histamine regulates gut function, the brain, spinal cord and uterus. It regulates the hypothalamic-pituitary axis (HPA axis), appetite, inflammation and pain perception. Some of the benefits of histamine is its functional role in helping with arousal, alertness, learning and memory.
The role of histamine is not something to be feared when performing its intended roles to help protect against pathogens and infections. However, in cases of allergic reactions and other extreme immune responses (such as asthma attack or hives), histamine can be an issue for some people.
Signs of excess histamine:
- headaches or migraines
- congestion or runny nose
- watery eyes
- asthma
- diarrhoea
- hives
- eczema or psoriasis
- facial flushing or rosacea
- tickling or crawling skin sensations
- hypotension (low blood pressure) or hypertension (high blood pressure)
- tachycardia (fast heart rate)
- vertigo
- anxiety
- fatigue
What leads to histamine overload?
Histamine can affect anyone. Triggers such as stress, excessive exercise and illness can boost your immune system response, leading to increased histamine release. These might be times that you need to support your histamine clearance or adjust some lifestyle factors to lower this overload. Sometimes you may need to reduce high histamine foods to let your body do some repair work.
When histamine is high, symptoms can become intense and prolonged — or simply show up unwanted, like when eating spicy foods. High histamine can occur with an exacerbated immune response and/or poor histamine breakdown and clearance. Stress, diet, lifestyle and genetics can all affect histamine levels.
This is not to say that histamine is the main player driving these symptoms and every case should be investigated further to determine the root cause. For some people, managing high circulating histamine can be a useful method to reducing the severity of symptoms.
Foods high in histamine:
- Fish (frozen/smoked/salted/canned)
- Aged or hard cheeses
- Red wine vinegar
- Meats
- Fermented vegetables
- Some vegetables (eggplant, spinach, avocado)
- Yoghurt
- Breads and foods baked with yeast
- Alcohol
Foods which can trigger the release of histamine:
- Some fruits (bananas, strawberries, citrus fruits)
- Chocolate and cacao
- shellfish
- Raw egg whites
- Nuts
- Spices
- Food additives
- Some vegetables (mushrooms, tomatoes)
Other foods can also inhibit the breakdown of histamine, including alcohol and some teas.
Support your genes for histamine breakdown
There are two genes which encode for the enzyme required to metabolise histamine. These are di-amine-oxidase (DAO) and histamine N-methyl transferase (HNMT). DAO acts to metabolise histamine within the gut, and HNMT acts within the cells throughout your body.
A useful way to help your body clear excess histamine is by supporting these genes and the enzymes they produce. One of the most effective nutrients for supporting these is the flavonol quercetin, which is found in a variety of fruits, vegetables and herbs. By decreasing the dietary histamine load and increasing quercetin, you can promote the clearance of excess histamine to help reduce associated symptoms.
If you’d like an in-depth assessment of how histamine might be affecting your health, book a discovery session with me to learn how clinical nutrition can assist you.
Cover image by Volodymyr Hryshchenko via Unsplash