Making an Informed Choice About Your DAO Supplement
If you are working with a healthcare professional and exploring the possibility of a DAO deficiency, part of your personalised plan may include trying a diamine oxidase (DAO) enzyme supplement. A quick look online and you'll see that this is a growing market with not just different brands (including our own, Aperitif) but with very different formulations, ingredients and price points as well. It's hard to know what to look out for, and what actually matters.
In this guide we want to give you clear, science-backed information, so you can better understand what to look out for and why Tolerance has made the decisions that we have when it comes to creating our own DAO enzyme supplement.
1. Enzyme Activity: Understanding HDUs
One of the first things that you'll notice on a label is the enzymatic activity, which is measured in what are called Histamine Degrading Units, or HDUs. This number tells you about the potential power of the enzyme in the supplement, not just the weight of the raw ingredient.
You can think of HDUs like the horsepower of a car engine. Two engines might be the same size, but their horsepower tells you how powerful they actually are. Similarly, two DAO capsules might contain the same milligram (mg) amount of porcine kidney extract, but their HDU value tells you how active that enzyme is expected to be. A higher HDU count indicates a higher potential for breaking down histamine.
This is why Tolerance's DAO enzyme supplement has a higher HDU count than other brands. Our supplements are formulated with 15% of your recommended daily intake of Vitamin C, which is an essential DAO cofactor. Looking for a clearly stated HDU value on the packaging is a key indicator of a transparent and quality product. It shows the manufacturer is focused on the supplement's functional activity, which is what matters most.
2. The Journey to the Gut: The Role of Enteric Coating
A DAO supplement has one very specific job: to break down ingested histamine from food and drink within your small intestine. To effectively do this, the enzyme has to survive the journey through the highly acidic environment of your stomach first. This is where an enteric coating becomes crucial.
An enteric coating is a specialised, protective layer on a capsule or tablet, which is designed to be resistant to stomach acid. It ensures the capsule passes through the stomach intact and only breaks down and releases the DAO enzyme once it reaches the more alkaline environment of the small intestine. This is where the enzyme is needed to interact with the histamine from your meal, so if the enzyme doesn't arrive there, the supplement is not going to be effective.
Without this protection, a significant portion of the delicate enzyme could be rendered inactive by stomach acid before it ever reaches its destination. You can learn more about this process in our guide to how a DAO supplement works in your digestive system. At Tolerance our DAO supplements contain this enteric coating, so you can trust that the enzymes are arriving where they are needed.
3. The Source of the Enzyme
The vast majority of clinically studied and widely used DAO supplements are derived from porcine (pig) kidney extract. The reason for this is that the DAO enzyme from this source is biochemically almost identical to the DAO enzyme produced by the human body. This similarity is important for its function in the gut.
While plant-based DAO alternatives derived from sources like pea shoots exist, there is currently less research on their efficacy in the human digestive system compared to their animal-derived counterparts. We explore this topic in much more detail in our article on Animal-Derived vs. Plant-Based DAO, which goes into the science behind this and explains why we chose to only produce DAO derived from porcine kidney extract.
A Simple Checklist for Choosing a DAO Supplement
When you are assessing your options, here are the key questions to consider:
- Is the enzyme activity clearly stated in HDUs? Look for a specific number on the label, not just a weight in milligrams
- Does the supplement have an enteric coating? This is vital to ensure the enzyme is protected from stomach acid and released in the small intestine
- What is the source of the enzyme? Understand where the DAO comes from and why the source material matters
Navigating the world of supplements can be complex, but by focusing on these key markers of quality, you can feel more confident in your choices. Our own supplement, Aperitif, was developed with these principles at its core, designed to provide a high-quality, reliable source of the DAO enzyme for those who need it.
This article is for informational purposes only and does not constitute medical advice. Please consult a qualified healthcare professional for advice specific to your situation.