Key Takeaways
- Histamine intolerance is caused by an imbalance of too much histamine compared to your capacity to break it down. This can be due to excess histamine from food, producing too much histamine, or not being able to break it down efficiently.
- Genetic variants (SNPs) in the genes encoding DAO and HNMT can reduce enzyme activity, which increases susceptibility to histamine intolerance.
- Histamine intolerance can cause a wide range of symptoms including: Headaches, migraines, anxiety, irritability, brain fog, acid reflux, nausea, bloating, diarrhea, arrhythmia, dizziness, sinus drainage, hives, itching, flushing, insomnia, and early waking.
- Understanding your genetic variants can help you target dietary changes, lifestyle modifications, and natural supplements to help with histamine intolerance symptoms.
Table 1: My Genetic Variants
TODO
Understanding Histamine's Multiple Roles
Histamine is a biogenic amine with many different functions in the body. It acts as a neurotransmitter in the brain, signaling for morning alertness and affecting mood. In the stomach, it signals the release of stomach acid for digestion. It plays a role in maintaining normal heart rhythm. In the lungs, histamine release causes bronchoconstriction, and during allergic reactions, mast cells release histamine, causing runny noses, watery eyes, and even anaphylaxis.
When eating foods high in histamine - such as fermented foods, wine, tomato sauce, and smoked meats - the DAO enzyme is produced in the intestines to break down histamine so it isn't absorbed into the body at high levels. Certain gut bacteria also produce histamine. Some people have a gut microbiome that has shifted toward higher histamine production, and some probiotics contain histamine-producing bacteria. Genetic variants that decrease DAO production can then lead to the symptoms of histamine intolerance when eating foods high in histamine.
Making the Connections
A bunch of other health conditions also involve elevated histamine levels. For someone with genetic susceptibility to low DAO production, dietary changes and the right probiotic may help with conditions such as asthma, migraines, heartburn, hypermobility EDS, ADHD, aFib, fibromyalgia, tinnitus, periodic limb movement disorder, autoinflammatory disorders, allergies, or brain fog.
Here are a few examples of these connections:
Asthma
Part of what occurs during asthma attacks is mast cell activation and histamine release, causing bronchoconstriction. Asthma medications act to reverse the bronchoconstriction, which is essential. However, zooming out to a systems-wide approach might include reducing high-histamine foods and avoiding histamine-producing probiotics to decrease attack frequency by changing the threshold at which bronchoconstriction occurs. I'm not suggesting that a low-histamine diet will cure asthma for everyone, but understanding how the body's histamine levels affect this system may be helpful.
Migraines
Migraines have multiple underlying causes, with high histamine levels being one possibility due to the histamine's role in altering blood flow. Reducing dietary histamine and changing the gut microbiome may change the threshold at which a migraine is triggered.
ADHD
Research shows multiple pathways are involved in ADHD, and high histamine levels may exacerbate the changes in brain function. While a low-histamine diet won't cure ADHD for everyone, being aware of how histamine from foods, the gut microbiome, and allergies influences brain function may lead to more understanding of how diet affects focus and attention.