Eating a diet rich in omega 3 fatty acids could ease migraines, research suggests.
Migraine is the third most common "disease" in the world, affecting around one in seven people.
An excessive caffeine or alcohol intake has long been linked to the onset of headaches. The impact of other aspects of our diet was less clear, however.
To learn more, scientists from the University of North Carolina analysed 182 people who endured a migraine on up to 20 days a month.
The participants were randomised to eat one of three diets, with varying amounts of omega fatty acids, for 16 weeks.
Results reveal those who ate more omega 3 fatty acids – found in oily fish like salmon, mackerel and sardines – while cutting back on omega 6 fatty acids, found in vegetable oils, went on to have fewer headaches.
Omega 3 fatty acids are precursors to molecules that regulate pain and inflammation, with this research taking experts "one step closer" to a "migraine diet backed up by robust results".
"This study provides a biologically plausible demonstration that pain can be treated through targeted dietary alterations in humans," the scientists wrote in the BMJ.
"Collective findings suggest causal mechanisms linking 3 and 6 fatty acids to [pain regulation] and open the door to new approaches for managing chronic pain in humans".
The typical Western diet tends to be low in omega 3 fatty acids and high in omega 6.
Both omega 3 and 6 fatty acids are precursors to oxylipins. Those derived from omega 3 are linked to reduced pain, while the reverse is true for omega 6.
Omega 3's potential as an anti-migraine supplement has thrown up mixed results in past studies.
The North Carolina scientists therefore set out to better understand whether a diet rich in omega 3 may increase levels of the oxylipin 17-hydroxydocosahexaenoic acid (17-HDHA), potentially easing headaches.
Nearly nine in 10 (88%) of the 182 migraine patients were women, who are three times more likely to endure the severe headache.
All the participants, average age 38, had between five and 20 migraines a month.
Those in the "control group" were put on a diet with "typical levels" of omega 3 and 6.
The second and third groups both raised their omega 3 intake. Meanwhile, the second group kept their omega 6 consumption the same as the control group and the third group lowered their intake.
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At the end of the 16 weeks, participants in the second and third group had higher 17-HDHA levels than those in the control cohort, however, this was not a statistically significant difference.
Nevertheless, the participants in both of these groups saw improvements to their headaches.
The high omega 3 – but normal omega 6 – diet was linked to 1.3 fewer hours of headaches per day. These participants also had two fewer "headache days" every month.
The high omega 3 and low omega 6 diet was associated with 1.7 fewer headache hours a day and four fewer headache days a month.
Nevertheless, these eased headaches were not linked to an improved quality of life.
The scientists have stressed the participants may have struggled to stick to their allocated eating plan, despite them receiving regular dietary counselling and access to online support. The results may also not apply to children, older people or men.
Nevertheless, Dr Rebecca Burch – from the Brigham and Women's Hospital – has said the findings "take us one step closer to a goal long sought by headache patients and those who care for them: a migraine diet backed up by robust clinical trial results".
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