“Migraine is among the largest causes of disability worldwide,” the authors of the study said. “Although treatment options for migraine have improved in the last decade, many patients continue to experience substantial pain and disability despite taking multiple drugs. As with many multifactorial chronic diseases, an incomplete understanding of the underlying biological mechanisms has limited development of effective approaches for prevention and treatment.”
A ROLE FOR DIETARY N-3 AND N-6 FATTY ACIDS IN MIGRAINE PATHOGENESIS
Modern industrialised diets tend to be low in omega-3 fatty acids and high in omega-6 fatty acids. These fatty acids are precursors to oxylipins – molecules involved in regulating pain and inflammation.
Oxylipins derived from omega-3 fatty acids are associated with pain-reducing effects, while oxylipins derived from omega-6 fatty acids worsen the pain and can provoke migraines. But previous studies evaluating omega-3 fatty acid supplements for migraine have been inconclusive.
So a team of US researchers wanted to find out whether diets rich in omega-3 fatty acids would increase levels of the pain-reducing 17-hydroxydocosahexaenoic acid (17-HDHA) and reduce the frequency and severity of headaches.
Their results are based on 182 patients at the University of North Carolina, USA (88% female; average age 38 years) with migraine headaches on 5-20 days per month who were randomly assigned to one of three diets for 16 weeks.
The control diet included typical levels of omega-3 and omega-6 fatty acids. Both interventional diets raised omega-3 fatty acid intake. One kept omega-6 acid intake the same as the control diet, and the other concurrently lowered omega-6 acid intake.
Over the 16 weeks, both interventional diets increased 17-HDHA levels compared with the control diet, and while HIT-6 scores improved in both interventional groups, they were not statistically significantly different from the control group.
However, headache frequency was statistically significantly decreased in both intervention groups.
The high omega-3 diet was associated with a reduction of 1.3 headache hours per day and two headache days per month. The high omega-3 plus low omega-6 diet group saw a reduction of 1.7 headache hours per day and four headache days per month, suggesting an additional benefit from lowering dietary omega-6 fatty acid.
Participants in the intervention groups also reported shorter and less severe headaches compared with those in the control group.
"While the diets did not significantly improve quality of life, they produced large, robust reductions in frequency and severity of headaches relative to the control diet," the authors stated.
"This study provides a biologically plausible demonstration that pain can be treated through targeted dietary alterations in humans. Collective findings suggest causal mechanisms linking n-3 and n-6 fatty acids to pain regulation and open the door to new approaches for managing chronic pain in humans," they conclude.
These results support recommending a high omega 3 diet to patients in clinical practice, said Rebecca Burch at the Brigham and Women's Hospital.
She acknowledged that interpretation of this study's findings is complex but points out that trials of recently approved drugs for migraine prevention reported reductions of around 2-2.5 headache days per month compared with placebo, suggesting that dietary intervention can be comparable or better.
What's more, many people with migraines are highly motivated and interested in dietary changes, she added. These 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."
