How can I establish whether I have an enzyme deficiency syndrome?

In case of histamine intolerance caused by enzyme deficiency, you may suffer from the most diverse intolerance reactions after consuming foodstuffs containing histamine.

Histamine intolerance occurs when the body is unable to adequately process levels of histamine, leading to one or more of many potential symptoms. These can range from mild skin rashes or headaches, to severe migraines, intestinal problems or chronic fatigue. Histamine is metabolized in the body by the enzyme diamine oxidase (DAO); when this is inhibited, or the body has abnormally low levels of the enzyme, histamine build-up eventually leads to the onset of symptoms.

Histamine not only occurs naturally, but can be produced by certain common foods - some contain large quantities of the amine, others release it, or block the action of DAO. Establishing the cause of the intolerance can take one of various forms, with some more reliable than others. Should you suspect you have a histamine intolerance, the key thing is to consult with a pharmacist or go and see your doctor, as they will be able to advise on how to test for an intolerance. The symptoms of histamine intolerance can also be very similar to those brought on by other medical conditions, so don't simply assume you have a histamine intolerance when there may be something else causing a problem.

The most common way to establish and deal with an intolerance is by a process of dietary elimination. Histamine is contained in large amounts in foods such as aged meats and cheeses, alcohol, and many other products. It is sensible to try eliminating certain trigger foods one at a time, rather than by the blanket withdrawal of a range of foods from the diet - that way you may never be sure which is the problem food. Once symptoms lessen or disappear, reintroduce the eliminated food(s) gradually. Should symptoms recur, you can then be fairly sure that you have identified the cause of the intolerance, and either remove it from the diet permanently or reduce consumption to a tolerable level.

A good way to monitor your food and alcohol intake is by keeping a food diary - if you experience symptoms regularly following the consumption of specific products, then you can relatively quickly identify a root cause and see whether the elimination method works. It can be very helpful to speak to a dietician before undertaking such a study - typically such a study should show results within 2-4 weeks.

In addition to elimination of food, there are several other tests that you can try to see if you have a histamine intolerance. Laboratory testing for DAO activity is one such option. Low DAO activity can be pinpointed in these tests, although this may not definitively be the cause of an intolerance, just a contributing element. Note that testing for DAO activity can be inaccurate should you already be on a low histamine diet - with lower levels of histamine to metabolise, your DAO activity will naturally be reduced. A blood test will establish both histamine and DAO levels, with a high histamine to DAO ratio clearly indicating there is an issue.