Cluster headaches are cripplingly painful headaches that can last for up to three hours and happen multiple times per day.
Most drugs are ineffective in treating cluster headaches. Researchers even use the term “drug-resistant” cluster headache to describe the difficulty in treating this condition[*].
A recent study found that a ketogenic diet lessened the frequency of symptoms in 18 chronic cluster headache patients[*]. Specifically, three months of keto dieting reduced cluster headache attacks, on average, by about 300%.
In this article, you’ll learn about this study, along with possible mechanisms by which keto may help with cluster headache. But first, let’s cover the basics of this headache disorder.
Cluster headaches are a disorder in which severe headaches—called “attacks”—arrive in clusters throughout the day.
A cluster headache attack is not a normal headache or a migraine. It’s a severe bout of pain that usually presents around the eye sockets, temples, and side of the head, and lasts anywhere from 15 to 180 minutes.
While experiencing an attack, the sufferer may become extremely agitated and even yell out in agony. According to some sources, cluster headache pain is “the worst pain known to man”[*].
Other symptoms may include:
- Runny nose
- Nasal congestion
- Drooping eyelids
- Facial sweating
Nasal spray can help with the stuffy nose, but it’s unlikely to improve the pain.
Cluster headache attacks may occur 0.5 to 8 times per day[*]. Some patients experience episodic cluster headache (with remission between cluster periods), while others suffer from chronic cluster headache (no remission periods). About 80 to 90% of cases are of the episodic variety[*].
Cluster headache may affect up to 0.4% of the population[*]. In Europe, it’s estimated that 600,000 people suffer from this debilitating condition, with over one third needing to miss work on its account[*].
Cluster headaches bewilders both patients and doctors, and effective treatment options are lacking.
Anti-migraine drugs like sumatriptan, imitrex, zolmitriptan, topiramate, prednisone, verapamil, and dihydroergotamine sometimes help, but often have little effect on the pain.
What Causes Cluster Headaches?
The pain of cluster headaches, researchers believe, results from the activation of the trigeminal nerve—a series of neurons (brain cells) that control sensations in the face, eye, and mouth regions[*].
The occipital nerve, and the surrounding blood vessels, may also be involved.
Researchers also hypothesize that a brain region called the hypothalamus plays a role in cluster headaches[*].
In patients with cluster headaches, the hypothalamus has problems producing melatonin (the sleep hormone), even in the context of appropriate light-dark cues. A few small studies show promise for melatonin supplements in the treatment and prevention of cluster headache[*].
Another group of researchers asked: Can a keto diet improve the symptoms of chronic cluster headache? Since keto had already been shown to control seizures and improve migraine symptoms, it seemed a worthwhile basis for a study. Keep reading to learn what they found.
In this 2018 study published in the journal Frontiers of Neurology, researchers put 18 patients with drug-resistant chronic cluster headache on a ketogenic diet for 12 weeks[*]. They wanted to see if the keto diet would work, as a preventive treatment, to reduce the frequency of attacks.
Specifically, the participants were put on a modified Atkins diet, which allows more protein than a classical keto diet. The diet was low-carb, moderate protein, and high-fat—and in line with what most people consider a ketogenic diet. Also, daily urine sticks confirmed the participants were in ketosis.
To promote the transition to a ketogenic state, participants were only allowed 10 grams of carbs per day during the first month. After this induction period, they were allowed 20 to 30 grams of carbs per day for the remainder of the study.
At baseline, the patients suffered an average of 108 cluster headache attacks (each) per month. Here are the average attacks after 1, 2, and 3 months of keto dieting[*]:
- Baseline: 108 attacks
- After 1 month of keto: 68 attacks
- After 2 months of keto: 49 attacks
- After 3 month of keto: 31 attacks
The attacks, according to this data, were reduced by over 300% after 3 months of ketogenic dieting. Also interesting: 11 of 18 participants experienced full resolution of symptoms (no headaches and pain-free) after three months on keto.
“The results of our observations as recorded by their diary and blood tests,” write the authors, “show that [keto dieting] is associated with an attack frequency reduction in [chronic cluster headache] patients, in the absence of any relevant side effects.”
Now let’s examine why a keto diet might help with the treatment of cluster headache.
Since it’s not clear what causes cluster headaches, it’s hard to pinpoint why the ketogenic diet helped. Here are some theories though.
#1: Increased Dopamine Activity
People with cluster headache have problems with dopamine—a neurotransmitter best known for stimulating feelings of reward[*]. In fact, treating a cluster headache patient with dopamine-stimulating drugs was shown to improve his symptoms[*].
Researchers believe that the same mechanisms that activate ketogenesis (ketone production) also stimulate the dopamine system—which may alleviate cluster headache[*].
#2: More GABA
The calming neurotransmitter known as gamma amino butyric acid (GABA) appears to protect against cluster headache. In fact, a drug that boosts GABA levels has been shown to be effective in reducing attacks[*].
Where does keto come in? The keto diet is linked, in both mice and humans, with increased levels of GABA in the brain[*].
Keto also reduces levels of glutamate—a neurotransmitter that, in excess, causes seizures and brain toxicity[*]. Reducing glutamate may create an environment less conducive to cluster headache attacks.
#3: Less Brain Inflammation
Brain inflammation refers to an immune response in the brain. The inflammation can either be acute (a head injury) or chronic (low grade, systemic inflammation).
Being in a state of ketosis can reduce brain inflammation by several mechanisms.
First, when ketones are metabolized in the brain, fewer reactive oxygen species (ROS) are produced compared to normal glucose metabolism[*]. Fewer ROS means less oxidative stress, and less oxidative stress means less inflammation.
Ketones also block an inflammatory process called the NLR3P inflammasome[*]. Basically, this means that less immune particles are needlessly called into action.
Finally, keto prevents spikes and crashes in blood sugar. High blood sugar (hyperglycemia), it’s been shown, can worsen existing brain damage—so it’s desirable to prevent those swings[*].
How does this relate to cluster headache? As with most problems in the brain, cluster headache is linked to inflammation[*]. And so the anti-inflammatory effect of keto may partly drive the headache reduction benefit.
#4: Increased Adenosine Signaling
When you get hurt or injured, your brain releases a potent chemical called adenosine. Adenosine is there to kill the pain.
Fun fact: The keto diet has been shown to boost adenosine activity in mice. Compared to control mice, mice on a keto diet had greater activation of adenosine receptors, and less seizures[*].
The link here to cluster headache here is fairly speculative, but some researchers believe that problems with adenosine signaling may contribute to its pathology[*].
A cluster headache attack is among the worst types of headaches imaginable. Unfortunately, many people who suffer from them can’t seem to get a break.
Recent research from Frontiers of Neurology suggests that keto may help with this crippling condition[*]. Of 18 patients with chronic cluster headache, 11 achieved full resolution after three months of keto dieting. Overall, the average number of attacks decreased by about 300%.
It’s not clear why, exactly, keto had these positive effects. There are likely several mechanisms at work. The keto diet, for instance, has been shown to increase dopamine, GABA, and adenosine activity—and also reduce brain inflammation.
Theoretically, these changes could explain how keto reduced the symptoms of cluster headaches. But to really get to the bottom of this, more research is needed.