Chocolate is widely cited as a common trigger for migraine attacks, but the relationship is far more complex than a simple cause-and-effect. A migraine is not merely a severe headache; it is a neurological event involving specific changes in the brain and nervous system. The belief that chocolate is a trigger is largely anecdotal, although it is one of the most frequently self-reported food triggers among migraine sufferers. The complexity of this link stems from the fact that chocolate contains several biologically active compounds that can influence brain chemistry and blood flow in sensitive individuals. Understanding what is actually in the cocoa bean provides insight into why this popular treat has been implicated in this debilitating neurological condition.
The Neuroactive Compounds in Chocolate
The cocoa bean contains several naturally occurring substances known to interact with the nervous and circulatory systems, making them the primary suspects in chocolate-related migraine attacks. The most commonly cited of these are the biogenic amines, Tyramine and Phenylethylamine (PEA), along with the methylxanthines, Caffeine and Theobromine. The concentration of these compounds varies significantly depending on the type and processing of the chocolate product.
Tyramine
Tyramine is a naturally occurring monoamine that forms when the amino acid tyrosine breaks down during fermentation, aging, or spoilage of food. Because cocoa beans undergo fermentation during processing, tyramine is present in chocolate, although its presence is highly variable and depends on the processing methods used. This compound is known to affect blood pressure and is often implicated in food-related headaches.
Phenylethylamine (PEA)
Phenylethylamine (PEA) is another biogenic amine, sometimes referred to as a natural stimulant, which is also present in cocoa. PEA is structurally similar to certain neurotransmitters and can influence dopamine and norepinephrine levels in the brain. The amount of PEA in chocolate is directly related to the non-fat cocoa content, meaning darker chocolate generally contains higher concentrations than milk chocolate.
Caffeine and Theobromine
Chocolate also naturally contains two methylxanthines: caffeine and its chemical relative, theobromine. Caffeine is a well-known vasoconstrictor, meaning it narrows blood vessels, and is a common ingredient in many over-the-counter headache medications. Theobromine is a milder stimulant, but it is present in significantly higher quantities in cocoa than caffeine, typically at a ratio of about 5-to-1.
The Proposed Biological Mechanism of Triggering
The compounds found in chocolate are hypothesized to trigger a migraine by initiating a cascade of biological events that affect the brain’s delicate chemical balance and vascular system. Tyramine is thought to potentially act as an indirect sympathomimetic agent, meaning it can cause the release of stored norepinephrine, a neurotransmitter that constricts blood vessels. In sensitive individuals, this initial vasoconstriction may be followed by a rebound vasodilation—the widening of blood vessels—which is a process linked to the onset of migraine pain.
Phenylethylamine (PEA) may contribute to the trigger mechanism by influencing the release and reuptake of neurotransmitters like dopamine and norepinephrine. An influx of these compounds can over-excite the nervous system, potentially lowering the brain’s threshold for a migraine attack. This chemical instability can disrupt the normal electrical activity in the brain, setting the stage for the neurological event.
The vascular effects of caffeine and theobromine are also part of the proposed mechanism, although their role is complicated. While caffeine can initially constrict blood vessels, which can sometimes relieve an early headache, a sudden increase or subsequent withdrawal can lead to the vasodilation phase. This rapid shift in blood vessel diameter is thought to activate the trigeminal nerve pathway, which transmits pain signals from the face and head to the brain, thus initiating the full migraine experience.
Furthermore, the release of certain compounds can also influence the production of nitric oxide (NO), a molecule that signals blood vessels to dilate. Cocoa flavanols have been shown to stimulate NO production, which may lead to the vasodilation that characterizes the pain phase of a migraine.
Factors That Complicate the Chocolate-Migraine Link
Despite the presence of neuroactive compounds, scientific studies using controlled, provocative testing have often failed to definitively prove chocolate as a consistent, universal migraine trigger. This ambiguity is due to several complicating factors, including the high variability of individual sensitivity among migraine sufferers. Only a small percentage of people with migraines report chocolate as a trigger, suggesting that a genetic predisposition or a low individual tolerance threshold is necessary for a reaction to occur.
Craving Versus Trigger Hypothesis
One of the most confounding issues is the “craving versus trigger” hypothesis, which suggests that the desire for chocolate may be an early symptom of the migraine’s prodrome phase, rather than the cause. The prodrome can begin hours or even a full day before the head pain starts, and it often includes mood changes and food cravings, particularly for sweet items. Consuming chocolate during this early phase can lead a person to mistakenly identify it as the trigger for the ensuing attack.
Non-Cocoa Additives
The specific composition of the consumed product further complicates the research, as many commercial chocolate bars contain numerous non-cocoa additives. Ingredients like high amounts of sugar, dairy products, or artificial flavorings may be the actual culprits for some individuals, rather than the cocoa solids themselves. Since these processed ingredients can independently affect blood sugar levels or contain other potential irritants, it is difficult to isolate the effect of the biogenic amines or methylxanthines from the cocoa bean.
Processing Variability
The way cocoa is processed also affects the final concentration of the suspected biogenic amines. For example, the fermentation process, which is necessary to develop the flavor, dictates the amount of tyramine and other amines present in the final product. This means that a highly processed milk chocolate might have a different chemical profile and trigger potential than a high-cacao dark chocolate, making a blanket assessment of “chocolate” inaccurate for all migraine patients.