Understanding Histamine: Two Key Sources
When you live with histamine intolerance, it can feel like you’re managing a constant balancing act. To understand the tools that might help, it’s crucial to first grasp where histamine comes from. Think of your body as having a ‘histamine bucket’. When this bucket overflows, you might experience reactions. The bucket gets filled from two distinct sources:
- External Histamine: This is the histamine you consume through your diet. It’s found in many common foods and drinks, especially those that are aged, fermented, or leftover. You can learn more in our guide to Histamine in Food & Drink
- Internal Histamine: This is the histamine your body produces itself. Your immune cells, called mast cells, release histamine in response to things like allergens, stress, injury, or hormonal changes
DAO enzyme supplements and antihistamines are often mentioned in the same breath, but they work on completely different sources of histamine. Understanding this difference is key to having an informed conversation with your healthcare provider.
How Do DAO Supplements Work on External Histamine?
Diamine oxidase (DAO) is the primary enzyme your digestive system uses to break down histamine from food and drink. If your body doesn’t produce enough of this enzyme, a condition known as DAO deficiency, the histamine from your meals can’t be broken down efficiently. This causes your histamine bucket to fill up quickly.
This is where a DAO supplement comes in. It is possible to make up for a lack of natural DAO by taking DAO supplements. A product like our Aperitif is designed to be taken 15 to 20 minutes prior to ingesting histamine-rich food or drink. The capsule dissolves in your small intestine, releasing the DAO enzyme exactly where it’s needed to help with the digestion of histamine from the meal you are about to eat. It acts on the external histamine in your gut, before it has a chance to be absorbed into your system.
How Do Antihistamines Work on Internal Histamine?
Antihistamines are medications that work in a completely different way. They don’t break down histamine at all. Instead, they work by blocking histamine receptors (like the H1 and H2 receptors) on cells throughout your body.
When your mast cells release internal histamine, it travels through your bloodstream looking for these receptors to bind to. By blocking the receptors, antihistamines prevent histamine from ‘docking’ and triggering a reaction. They essentially manage the effects of the histamine your body has already produced. They do not, however, have any effect on the histamine sitting in your gut from the food you’ve just eaten.
We explore this further in our article on hay fever and histamine intolerance.
A Simple Analogy: The Kitchen Sink
To make it clearer, let’s imagine your histamine bucket is a kitchen sink:
- External (food) histamine is the water flowing into the sink from the tap. A DAO supplement is like a powerful drain unblocker; it helps the water (histamine) drain away efficiently before the sink can overflow
- Internal (body) histamine is like a slow leak from a pipe under the sink. An antihistamine is like putting a towel on the floor to soak up the water that has already leaked out. It manages the mess, but it doesn’t fix the leak or help the sink drain any faster
This analogy shows they are two different tools for two different problems.
Can You Use Both?
Because DAO supplements and antihistamines work on different pathways (one on food in the gut, the other on receptors in the body), they are not mutually exclusive. However, antihistamines are medications, and any decision about using them, or using them in combination with supplements, should only be made in consultation with your doctor, pharmacist, or a qualified healthcare professional who understands your personal health history.
Finding Your Path Forward
As ever when it comes to histamine intolerance, the most crucial thing is understanding, in this case the different roles that these two substances play in our bodies. A DAO supplement is a dietary tool intended to support the breakdown of histamine from food for people with a DAO deficiency. An antihistamine is a medication that manages your body’s reaction to its own histamine release.
Navigating histamine intolerance is a unique and personal process. We always encourage working with a registered dietitian or healthcare provider to find a sustainable, long-term strategy. You can find a list of practitioners we trust on our About page. A professional can help you use tools like a temporary low-histamine diet to identify your triggers and build a plan that works for you.
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.