A diamine oxidase (DAO) deficiency is one of the most common causes of histamine intolerance. The DAO enzyme is responsible for breaking down histamine in your body. When it can’t break everything down, a build up occurs and you experience histamine intolerance symptoms.
You can take a DAO supplement, but there are also easy-to-make subtle shifts in your eating habits that promote healthy DAO enzyme levels, too.
Before we get into solutions, let’s take a look at what histamine intolerance is and what role the DAO enzyme plays in affecting histamine levels.
DAO and histamine intolerance
Research shows that at least 1 percent of the world’s population suffers from histamine intolerance and, of those, almost 80% affected are middle-aged women.
Histamine Intolerance occurs due to the overproduction and accumulation of histamine in the body and the inability to break it down. This may cause a range of chronic symptoms, such as a allergic-like reaction, digestive tract disorders (IBS), congestion, and asthma, among others.
Although it can be diagnosed by consulting a doctor and observing common symptoms of histamine intolerance, going deeper to find the root cause is vital for managing the symptoms. One common cause is a shortage of DAO enzymes.
In fact, studies show that DAO deficiency accounts for over 70% of all histamine intolerance.
So, how do you know if this is a root cause in your histamine intolerance?
Diamine oxidase deficiency: common causes
When your body needs to decrease its histamine levels, it requires two naturally occurring enzymes known as the DAO enzyme and histamine N-methyltransferase (HNMT). If these enzymes aren’t available, or if your body cannot produce enough, it can cause a histamine build-up.
There are several factors that may cause DAO deficiency, including:
- Genetic inheritance - Individuals may possess a genetic mutation which results in a diamine oxidase enzyme deficiency.
- Medications – Both prescription and over-the-counter medications may contribute to reduced diamine oxidase enzyme levels. It’s important to talk to your doctor about side effects and read the labels.
- Hormonal imbalances - Imbalances in oestrogen and progesterone can impact many of your body’s normal functions, including histamine levels.
- Gastrointestinal disorders - Disorders such as irritable bowel syndrome (IBS), Crohn’s disease, ulcerative colitis, Celiac disease and small intestinal bacterial overgrowth (SIBO) may all contribute to inflammation in your body causing similar symptoms as a histamine intolerance and even impacting your body’s ability to produce proper amounts of the DAO enzyme.
- Nutrient deficiencies - A B6, vitamin C, zinc or copper deficiency, may put you at risk or contribute to a DAO deficiency.
- Consuming histamine-rich food - Some foods may inhibit the functioning of the DAO enzyme, or contribute to symptoms by overloading the body with more histamine than your enzymes can break down.
- Alcohol - Alcohol is a very potent inhibitor of the DAO enzyme, thus contributing to increased histamine symptoms, on top of being high in histamine itself.
A DAO deficiency can also impact multiple organs (lungs, skin, cardiovascular system, brain, digestion, etc.) leading to numerous additional symptoms. Depending on the severity of the deficiency, these symptoms can occur after eating certain foods.
It's also important to note that symptoms don’t always appear immediately, either. It may take all day for your body to accumulate a buildup of histamine. So, the meal you ate in the morning may have caused the drowsiness or skin irritation you are feeling now.
Because it can be difficult to pinpoint the triggers, many people find that an elimination diet full of low histamine foods is helpful for identifying histamine intolerance and understanding which foods to avoid, but we will cover some of those foods below.
8 ways to increase DAO enzymes naturally
To date, there have been many studies on preventing DAO deficiency in the body and researchers have even identified options to potentially prevent and even reverse histamine intolerance.
1. Adopt a low histamine diet
A recent study found that dietary modification is the first step for reducing symptoms associated with histamine intolerance. By eliminating high histamine foods from your diet, you are allowing your body to catch up to and process the amount that is already present. The study also discovered that these dietary modifications positively impacted how DAO enzymes move throughout your body.
If you aren’t sure how the right diet can reduce your histamine levels and support healthy DAO production, click the button below to download my free eBook. It is a master list of 102 high histamine foods to avoid, along with step-by-step guidance for reducing your symptoms and discovering the root cause of your intolerance.
2. Balance your fat intake
When it comes to updating your diet, some of the most interesting and relevant results for increasing DAO enzymes have been in relation to fat consumption.
Studies have shown favourable results when patients increased their intake of the Omega-9 fatty acid - monounsaturated fats, a primary source of oleic acid. Olive oil in particular was shown to increase the the release of the DAO enzyme into the bloodstream by up to 500%!
Oleic acid has been shown to have other health benefits, too, such as reduced blood pressure, especially when consumed as part of a Mediterranean-style diet. You can cook with olive oil or include nuts like macadamias in your meal plan to help prevent a DAO deficiency.
Meanwhile, the inflammatory Arachidonic Acid, a polyunsaturated omega-6 fatty acid, found in offal, fatty red meat and dairy (especially hard cheeses and eggs) was found to cause the highest increase in histamine, when compared to other foods.
Reducing the amount of Omega-6 in your diet - the kind found in processed foods and vegetable oils - while increasing the amount of Omega-3 fatty acids (including fatty fish, seafood) you eat has been shown to moderate inflammation and reduce symptoms of histamine intolerance.
Important factors in balancing fats include using heat stable oils, including ghee and pressed coconut oil for baking and cooking at high temperatures. You can regularly use olive oil and macadamia oil for light, low heat cooking.
3. Eat the right proteins
The process of digesting protein is largely responsible for the release of the DAO enzyme in the gut. This helps your body deal with ingested amines and histamines, while preventing a build-up of histamine levels in the body.
Therefore, eating clean, healthy proteins is important. Look for grass-fed, organic protein and fresh seafood to increase DAO activity.
4. Minimize harmful ingredients
A common theme in this list is healthy, whole foods. That’s not an accident! It’s important to understand that avoiding artificial ingredients and pesticides can make a huge impact on your digestion, DAO production and even food allergies.
Eating as naturally as possible is always going to be a positive for your health!
5. Supporting gut health
As mentioned, the majority of DAO histamine is produced in the gut. Therefore, promoting your gut health and supporting your gut bacteria through the use of low histamine probiotics provides an important foundation for reducing histamine symptoms. Probiotics are able to increase DAO just like a supplement, through the method of supporting your digestive tract and keeping gut bacteria at healthy levels.
6. Take vitamin supplements
Deficiencies of zinc, copper, vitamin B6 and vitamin C, have also been associated with inflammation, elevated histamine concentrations and reduced DAO activities. Regular supplementation of these nutrients can increase DAO enzymes and may offer further relief from the symptoms of histamine intolerance.
To understand which supplements and amounts are right for you, talk to your healthcare practitioner and/or work with a certified professional to ensure you are making the best selections.
7. Find a DAO supplement
Another simple way to increase your DAO enzyme levels are with a natural DAO supplement. These can be taken as a pill and may offer an easy way to help reduce symptoms of histamine intolerance.
It can be difficult however, to find DAO supplements and they may not work for people with a vegan diet, as they are typically isolated from a porcine kidney protein concentrate.
Although I don't personally use a DAO supplement with my clients (I'll explain the method I use in the next section), you can find some decent options on Amazon, here.
8. Reduce histamine release
This is the method I use with many of my clients via supplementation with Natural D-Hist. Although reducing histamine release doesn't directly increase the DAO enzyme, it does give your body a break from the inflammation and destruction in order to allow the DAO enzyme to catch up and calm your symptoms.
Additionally, by controlling the body's natural histamine release, my clients typically find they can tolerate much higher levels of dietary histamine before their body becomes overloaded and shows symptoms.
This means less dietary restrictions and fewer symptoms. Yes, you can eat a wide variety of foods and live a normal daily life with histamine intolerance!
Some of my clients have called Natural D-Hist their "miracle in a bottle" or their "wonder-drug."
Implementing changes to improve histamine symptoms
Now that you have 8 ways to naturally prevent DAO deficiency, it's time to get started.
The steps above are all simple and can be done in your own home - so, I encourage you to begin implementing them right away. Why wait?
And, if you haven't already read the low histamine diet eBook I've created, click on the button below. It is the most comprehensive high histamine foods list available online, with additional methods for symptom relief and instructions on how to discover the root cause of your intolerance.