DAO Testing: Is it Worth it for Suspected Histamine Intolerance?

Histamine intolerance is gaining attention, especially among those dealing with unexplained symptoms like headaches, digestive problems, and skin reactions.

The enzyme diamine oxidase (DAO) plays a key role in helping the body break down histamine; you can learn more about this helpful /enzyme and DAO deficiency here

For most of our clients who suspect they have histamine intolerance, there is one question that we nearly always get asked: Is DAO testing a worthy investment for me?

In this article, we will discuss different methods of testing for DAO deficiency, their accuracy, factors impacting DAO levels, how to identify reliable tests, and some alternative ideas to think about.

Types of Testing for DAO Deficiency

Testing for DAO deficiency generally includes various methods, such as:

Blood Tests: this can measure either the total concentration of DAO in the bloodstream, or the activity of DAO enzyme in the blood.

Urine Tests: These tests advertised as being able to assess your body's histamine processing through urine samples. They claim to provide insights into how well the body is breaking down histamine and may additionally reflect DAO activity.

Genetic Testing: Genetic tests analyse DNA for genetic mutations linked to lower DAO enzyme activity and can only tell you if there is a primary (genetic) cause of DAO deficiency. It cannot tell you if you have DAO deficiency for another reason.

While these tests can shed light on your condition, their accuracy can sometimes be less than ideal.

Factors Affecting Accuracy

There are several factors that can affect the accuracy of results for blood and urine testing of DAO:

Timing: DAO levels fluctuate throughout the day based on diet and stress. Testing at different times can lead to varying results, which may confuse diagnosis. For instance, one study found that DAO levels were up to 30% higher in the morning compared to evening samples.

Microbiome Influence: The gut microbiome plays an interesting role in histamine metabolism. An imbalance, termed dysbiosis, can impede DAO production, impacting test results. New studies indicate that a healthy microbiome can boost DAO activity. For example, certain probiotic strains, such as Lactobacillus rhamnosus, have been linked to enhanced histamine breakdown.

Other Biochemical Processes: Medications, like certain antibiotics and underlying diseases can alter DAO levels. This variability makes it complex to rely solely on DAO tests for clear diagnoses.

Dietary Influence: Certain foods can temporarily impact DAO levels. For example, consuming high-histamine foods, such as aged cheeses and fermented products, can provoke symptoms and disrupt DAO activity.

Hormonal Effects: Hormones, particularly estrogen, can affect DAO levels. Studies suggest that women may experience variations in DAO activity during different phases of their menstrual cycle, underscoring the need for careful timing when testing. During pregnancy, DAO levels typically increase more than 500 times normal levels.

Given these variables, one DAO test alone may not capture the entire picture of a person's histamine intolerance.

How to Know if Tests are Reputable

Before undergoing DAO testing, it's essential to assess the test's credibility. Here are some tips:

Accreditation: Choose labs certified by recognised organisations. Endorsement or certification indicates that the company may be striving for reliable testing standards.

Consultation with Healthcare Providers: Engaging with knowledgeable healthcare professionals can help clarify which tests are clinically validated and tailored to your needs.

Client Reviews: Reading experiences shared by other patients can provide insights into the reliability of a particular testing service.

What Happens If You Receive a Positive Test Result?

Receiving a positive test result for DAO deficiency can be surprising for some. For many, however, it can be the moment that all of thier symptoms suddenly make sense. It is important to take a moment to make sure that your next steps are safe for you to carry out. We recommend that you:

Consult Your Healthcare Provider: Discuss the results with a healthcare professional who can suggest ways to manage symptoms.

Lifestyle Adjustments: Modifying your diet can have positive effects. Reducing intake of processed and high-histamine foods, while focusing on fresh produce, may help to improve symptoms. However, this should be done safely and under the right guidance by a Dietitian.

DAO Supplements: Taking a DAO supplement before you eat can help break down dietary histamines before they pass through the lining of the gut and enter the bloodstream.

Gut Health Improvements: Concentrating on gut health through probiotics and dietary changes could lead to a more balanced gut microbiome, which may help manage symptoms without needing laboratory testing.

Further Evaluation: Exploring other underlying health conditions could provide further insight into your histamine intolerance symptoms.

Understanding DAO Deficiency and Histamine Intolerance

It's crucial to grasp that DAO deficiency and histamine intolerance aren't always linked..

It may be surprising to know that most of our clients who join the Histamine Rebalance Programme have not decided to carry out DAO testing.

This is because histamine Intolerance and DAO deficiency are not always linked and not everyone with a histamine intolerance will show signs of DAO deficiency in testing.

As the management and considerations are just the same for histamine intolerance whether you have DAO deficiency or not, it actually isn't necessary.

Final Thoughts

DAO testing can provide insights and may help to diagnose histamine intolerance, but it has limitations. Factors such as timing, gut health, and hormonal influences can complicate interpretations. Additionally, not everyone with histamine intolerance displays a detectable DAO deficiency.

With these complexities in mind, consider DAO testing as part of a broader assessment. It is best used alongside other diagnostic methods and always under the guidance of a healthcare professional. While DAO testing can be informative, it can be unnecessary for exploring if you have histamine intolerance.

Known as the Histamine Expert Dietitians, Rosie and Catherine are registered Dietitians who help clients overcome the symptoms of Histamine Intolerance and DAO deficiency by using their signature Histamine Rebalance Programme.

Laboratory technicians working with equipment, used to represent DAO testing