You avoid trigger foods, yet migraines still strike. Here's the genetic reason.

MTHFR encodes an enzyme that sits at the center of your methylation cycle. It activates folate and B12 from food into their usable forms. These activated B vitamins are cofactors in hundreds of reactions, including the production of nitric oxide, a molecule that controls blood vessel dilation and constriction.

The C677T variant, carried by roughly 40% of people with European ancestry, reduces this enzyme’s activity by 40 to 70%. That means your cells aren’t converting dietary folate and B12 into their active forms efficiently. Homocysteine builds up. Your vascular tone becomes dysregulated. You’re functionally deficient in activated B vitamins even though you might eat plenty of them.

For you, this means your blood vessels are primed for the constriction-dilation cycle that migraine brings. Add tyramine on top, and your cerebrovascular system overreacts. Homocysteine amplifies neuronal excitability. A migraine becomes inevitable.

AOC1 encodes a copper-dependent enzyme called copper-containing amine oxidase (CAO), also known as semicarbazide-sensitive amine oxidase (SSAO). This enzyme’s job is straightforward: break down tyramine in the gut and bloodstream before it reaches your brain and triggers blood vessel constriction.

Variants in AOC1 reduce enzyme activity. When your AOC1 function is compromised, tyramine isn’t metabolized efficiently. It accumulates in your bloodstream and crosses into your nervous system, where it triggers norepinephrine and dopamine release from nerve terminals, causing the vasoconstriction that initiates migraine. Roughly 30 to 40% of people with migraine carry AOC1 variants that impair function.

For you, this is the most direct cause-and-effect relationship. Tyramine in food goes directly to elevated blood pressure and vasoconstriction. Your migraine doesn’t need multiple triggers. One aged cheese plate is enough.

COMT encodes catechol-O-methyltransferase, the enzyme responsible for breaking down dopamine, norepinephrine, and epinephrine. When COMT function is normal, these neurotransmitters are quickly cleared, keeping your nervous system calm and pain signals appropriately gated.

The Val158Met variant, present in roughly 25% of people homozygous for the slow version, reduces COMT’s activity. Dopamine and norepinephrine accumulate in your synapses, amplifying pain signaling through the trigeminal system and lowering your migraine threshold. You become more sensitive to any trigger, including tyramine.

For you, this means your pain modulation system is already compromised. Tyramine hits a nervous system that’s already overactive. Dopamine is flooding your synapses. The combination triggers migraine more easily than it would in someone with normal COMT function.

MAOA encodes monoamine oxidase A, an enzyme that breaks down serotonin, norepinephrine, dopamine, and tyramine. When MAOA function is optimal, these neurotransmitters stay in balance. When MAOA activity is low, serotonin and norepinephrine accumulate and tyramine clearance slows.

Low MAOA activity variants are less common but when present, have a strong effect. People with low-activity MAOA variants are extremely sensitive to dietary tyramine because they lack the enzymatic capacity to metabolize it alongside their other monoamine-metabolizing duties. This creates a compounding effect: tyramine accumulates, and serotonin dysregulation intensifies.

For you, this means you’re hypersensitive to tyramine and particularly vulnerable to the serotonin dysregulation that migraine brings. A small amount of tyramine can trigger a disproportionate response because your monoamine metabolism is already running at capacity.

NOS3 encodes endothelial nitric oxide synthase, the enzyme that produces nitric oxide in the cells lining your blood vessels. Nitric oxide is the master regulator of vascular tone. It tells your blood vessels when to relax and dilate. Without adequate nitric oxide, blood vessels become stiff, reactive, and prone to the constriction-dilation cycles that migraine creates.

The Glu298Asp variant, carried by roughly 30 to 40% of the population, reduces NOS3 enzyme activity by 20 to 30%. Your blood vessels have less nitric oxide available, making them hypersensitive to any vasoconstrictor signal, including the norepinephrine surge that tyramine triggers. Your cerebrovascular system is already primed for dysregulation.

For you, this means tyramine-induced norepinephrine release hits a vascular system that’s already running on low nitric oxide. The vasoconstriction phase of migraine is exaggerated. Blood flow to your brain drops further and faster.

SLC6A4 encodes the serotonin transporter, the protein that reuptakes serotonin from synapses back into nerve terminals, controlling how long serotonin remains active in your nervous system. Serotonin dysregulation is central to migraine pathophysiology. Low serotonin availability is part of what triggers the migraine cascade.

The 5-HTTLPR short allele variant, carried by roughly 40% of people with at least one copy, reduces serotonin reuptake efficiency. Your serotonin availability drops, your mood becomes more reactive, and your pain threshold lowers. Tyramine sensitivity worsens because serotonin dysregulation amplifies your response to any neurotransmitter perturbation.

For you, this means your nervous system is already running serotonin-depleted. When tyramine hits and triggers norepinephrine release, you have less serotonin available to counterbalance it. Migraine becomes more likely and more severe.