Histamine Intolerance

Histamine is a chemical which occurs naturally in certain foods. This is also one of the chemicals that is released in the body as part of an allergic reaction, causing the typical itching, sneezing, wheezing and swelling allergy symptoms.

We all have an enzyme (diamine oxidase) which breaks down any histamine that we absorb from a histamine-containing food. When we eat a food which contains histamine it does not affect us. However, some people have a low level of this enzyme. When they eat too many histamine-rich foods they may suffer ‘allergy-like’ symptoms such as headaches, rashes, itching, diarrhoea, and vomiting or abdominal pain. This is called histamine intolerance.

Foods that are particularly high in histamine and other vasoactive amines include:

• Champagne, wine, beer, cider and other fermented drinks and spirits
• Sauerkraut and other pickled foods
• Vinegar and foods containing it such as dressings, pickles, mayonnaise, ketchup, mustard
• Tofu and soya sauce
• Parmesan cheese and other cheeses
• Sausages and other processed meats (ham, salami, gammon, bacon)
• Mushrooms and quorn
• Tinned and smoked fish (tuna, salmon, herring) and crustaceans
• Prepared salads
• Tinned vegetables
• Dried fruit, seeds, nuts
• Yeast extract, yeast
• Chocolate, cocoa, cola

Certain foods (even food that is low in histamine) can stimulate the release of histamine from mast cells in your body (a type of immune cell). These foods include:

• Bananas
• Tomatoes
• Strawberries
• Nuts
• Peanuts
• Shellfish
• Egg white
• Chocolate
• Pumpkin
• Spinach
• Aubergines
• Avocado
• Papayas
• Kiwi
• Pineapple
• Mango
• Raspberry
• Tangerines
• Grapefruits
• Red prunes
• Pea
• Spices

It should be noted that allergy tests measuring IgE levels, such as skin prick testing and specific IgE blood tests for these foods will be negative. This is because reactions to histamine are not caused by an IgE food allergy – the cause is histamine intolerance.

Diagnosis of histamine intolerance is usually made by a person trialling a low-histamine diet for a couple of weeks, and seeing if their symptoms improve. Blood tests that claim to be helpful in measuring levels of histamine or the level of the enzyme that normally breaks histamine down are not reliable.

Treatment consists of avoiding histamine-rich foods but only to the level that is required by an individual. The amount of histamine rich foods tolerated will vary from person to person. Taking a regular antihistamine is often helpful.

Food exclusion should always be followed by a period of reintroduction in order to confirm a diagnosis. If this is not done the diet can easily become over restricted and unmanageable. At worst it can become nutritionally deficient.