Out of all the nootropics consumed world-wide, caffeine is the most common and available cognitive-enhancing substance. It’s become so ubiquitous that we have even found it in donated blood samples. As it’s widely over-used and our caffeinated drinks are only becoming bigger over time, caffeine dependency is also on the rise. For migraine sufferers, it can either cure a migraine if drank during or at the onset of an attack; but for others, consuming the tiniest amount can trigger a grueling migraine. This summer, researchers tried to come to a consensus about caffeine and migraines once and for all.
Eighty percent of the world drinks caffeine in some form, whether in coffee, chocolate, tea, soft drinks, or supercharged energy drinks and pre-workout mixes. The average consumption is around 300-400 mg daily. You can visualize this amount in about 4 or 5 cups of coffee. It’s become ingrained in many cultures around the world, but I’d bet very few of us even understand what caffeine does inside the body.
After we drink our beloved caffeinated beverages, it crosses the blood-brain barrier. It can usually be consumed in moderation without any side effects, but too much caffeine can cause jitteriness, anxiety, tremors, drowsiness, faster heart rate, and increase blood pressure. It can also cause a headache—so how do we explain why it seems to help some migraine sufferers?
Caffeine & Blood Flow
Caffeine affects cerebral blood flow within the brain. In a phenomenon known as the “coffee paradox,” it increases blood flow only in the endothelium (the lining of structures like blood vessels and lymphatic vessels) but does not increase blood flow to the smooth muscle of the vascular system. Simply put, caffeine can cause either a constriction or a dilation of the vascular system.
It’s the constriction of the vessels (vasoconstriction) that reduces cerebral blood flow. When scientists tested tea versus decaffeinated tea, they found a 20% decrease in cerebral blood flow within the brain’s gray matter that was unique only to caffeinated tea.
Caffeine & Pain
Caffeine works on receptors in the body called adenosine receptors, which is why it has pain relieving properties. The adenosine receptors affect pain signaling. Caffeine blocks adenosine receptors both peripherally and centrally within the body. Combining 100 mg of caffeine or less with a standard analgesic (such as acetaminophen or aspirin) relieves pain for most people to a bearable level that actually reduces the amount of standard pain-relieving medications needed.
This is why Excedrin contains acetaminophen, aspirin, and caffeine.
Caffeine & Migraines
Caffeine’s effects on blood flow was first suggested to be the mechanism behind why it works for migraines. Part of this was hinged in the belief that a migraine occurred because of a blood vessel/vascular disorder, but we now regard migraines as a neurological event. Adenosine is a neuromodulator that is closely linked to the current understanding of migraines. In fact, plasma levels of adenosine increase when you have a migraine.
Since caffeine blocks adenosine receptors, it can effectively block the effects of rising adenosine levels during an acute migraine attack. However, rebound headaches are real—and taking too much caffeine or analgesics (such as Excedrin) which contain caffeine can cause more headaches as you discontinue the medications. Therefore, the dose is in the poison, as they say.
Trigger or Ally?
This past summer, researchers from Poland published a review of all scientific studies which either claimed caffeine was good or bad for migraines. They found 21 studies which looked into caffeine (or the withdrawal from caffeine) as a migraine trigger. Seven studies were found which pointed to caffeine as an effective migraine treatment.
About 2-30% of people in the studies could genuinely identify caffeine as being a migraine trigger, but the rest of the studies found that caffeine or caffeine in addition to standard over-the-counter analgesics actually helped migraines.
It’s important to note that caffeine isn’t a preventative treatment for migraines and that these studies found relief when caffeine was consumed during an attack.
How Much Caffeine for Migraine Sufferers?
Caffeine withdrawal can trigger migraines for people who are already predisposed to migraines, so the authors of this most recent study suggest that people who have migraines should have a maximum of 200 mg daily. This is about 1-2 cups of coffee—but these are 8 oz cups of standard coffee. If you’re drinking Starbucks Dark Roast, you can expect to clock in 130 mg in their short 8 oz serving. Black tea brewed from a bag will usually give around 40 mg depending on how long its brewed. Coca-cola has about 34 mg per can, with Diet Coke containing 46 mg per can.
However much caffeine you choose to drink, consistency is key for people who are prone to migraines. Keeping your caffeine consumption moderate and as consistent as possible will decrease the risk of migraines triggered from caffeine withdrawal.
For some people, caffeine is off-limits, and others choose only to drink it if the proverbial jagged lines and light sensitivity indicates a migraine has begun. Keep doing whatever is working for you, and speak with your doctor about your magnesium levels, as magnesium is a great supplement for migraine sufferers. If you’re drinking caffeine, you’re also depleting your magnesium, so be sure to make whole-grain choices, eat plenty of leafy greens, and see if a supplement is right for you.
Nowaczewska, Magdalena, et al. “The Ambiguous Role of Caffeine in Migraine Headache: From Trigger to Treatment.” Nutrients, vol. 12, no. 8, 2020, p. 2259., doi:10.3390/nu12082259.