If you suffer from histamine intolerance, the most effective treatment is to avoid high histamine foods.

What is histamine intolerance?

Histamine is an inflammatory substance produced by cells in the body during infection. It encourages an immune response to help fight off viruses and bacteria. Histamine is also found naturally in many foods.

The lack of an enzyme called diamine oxidase (DAO) is thought to be an underlying cause of a histamine intolerance. DAO breaks down histamines in the body and when levels increase, this leads to symptoms.

Symptoms of histamine intolerance

Symptoms are “allergy-like” and include:

• Headache

• Asthma

• Runny or blocked nose

• Low blood pressure

• Irregular heartbeat

• Hives

• Itching

• Diarrhoea

• Flushing and other conditions

They can occur 30 minutes or longer after eating histamine-rich foods.

Histamine diet rules

Most people can tolerate the low level of histamine in normal diets. High histamine foods can be a trigger though, and for some people, even low levels are a problem.

If sensitivity or intolerance is suspected, you should seek advice from your GP. A low histamine diet is advised under the supervision of a registered dietitian. The diet involves avoiding high histamine foods for a short time (two-four weeks), monitoring for symptoms, then reintroducing them gradually to assess tolerance.

Histamine is found in many foods and levels vary making it difficult to produce an accurate food list. Common trigger foods and drinks include:

• Tinned, fermented or pickled fish

• Fermented dairy such as aged cheese

• Cured or processed meats

• Fruit and vegetables such as oranges, bananas, spinach and tomatoes

• Wine and beer

• Some nuts such as peanuts and tree nuts

As a rule, fresh foods should be eaten over ready meals or food that has been aged or stored for longer periods, due to the potential of higher histamine levels.

Histamine & long Covid

Histamine intolerance has recently been suggested in the management of long Covid because the symptoms of histamine intolerance are like those reported by people living with long Covid. Caution is advised as further research is needed before this can be recommended.

Histamine intolerance watch-outs

Unfortunately, histamine intolerance cannot be diagnosed by a simple test and food allergy testing won’t help as it's not a true allergy. Since histamine occurs naturally in many foods, following a low histamine diet can be highly restrictive and may lead to nutritional deficiencies if not supervised by a registered dietitian.

To find out more about histamine intolerance, head here.


Dietary interventions may not suit everyone. Restrictive diets can lead to nutrient inadequacies (especially if the diet isn’t planned carefully), problems sticking to the diet when socialising and eating out, and side effects are common.

We advise customers to check with their doctor before starting any restrictive diet to ensure it is suitable for them. This is important for people who are pregnant, breastfeeding, underweight, under 16 years of age, have a current medical condition or want to lose a large amount of weight. Restrictive eating plans may encourage disordered eating and appeal to people with pre-existing eating disorders.