Eating a portion of oily fish a day protects against headaches and migraines, a new study found.
Around six million people in the UK suffer with migraines and the condition can lead to debilitating pain lasting for several hours.
Researchers from the National Institutes of Health in the US assessed the role of diet in migraine prevention.
A study of 182 migraine-prone patients saw sufferers divided into three groups: a normal diet; elevated omega-3; and higher omega-3 with lower levels of omega-6.
Omega-3 is found naturally in oily fish such as sardines and salmon, and the human body cannot produce it itself.
The average intake of omega-3 is 150mg a day, but the scientists boosted this in the study to 1.5 grams daily – equivalent to one portion of cooked salmon, herring or mackerel.
People in the study suffered with migraines to varying degrees, ranging from five a month up to 20 migraine days a month.
Data found those who stuck to a high omega-3 diet for 16 weeks had two fewer headaches every month. The migraines they did suffer were also shorter, and less intense, the researchers said.
But the impact was more significant for those who had both high omega-3 and low omega-6 levels. For this cohort, the number of monthly headaches dropped by four.
Omega-6, also known as linoleic acid, is found in high levels in tofu, avocado oil and peanut butter as well as in processed foods.
People in the study were given ample food supplies as well as custom-made cooking oils and butters to precisely control their intake of both omega-3 and omega-6.
The diet plan which restricted omega-6 intake saw the standard dietary level of linoleic acid slashed by almost 75 per cent to just 1.8 per cent of a person’s daily calories.
"This study provides a biologically plausible demonstration that pain can be treated through targeted dietary alterations in humans,” the researchers said.
“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 concluded.
Dr Rebecca Burch, a doctor at the Graham Headache Centre at Harvard Medical School, who was not involved with the study, explained how diet may alter headache risk.
“Omega-3 and omega-6 fatty acids are precursors to oxylipins, which are involved in the regulation of pain and inflammation,” she wrote in an editorial article, published alongside the new research in the British Medical Journal.
“Omega-3 fatty acid derivatives are associated with [blocking pain] and anti-inflammatory effects, while oxylipins derived from omega-6 fatty acids worsen pain and provoke migraine in experimental models.”
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The researchers speculated a diet rich in omega-3 fatty acids increases a person’s production of a chemical called 17-hydroxydocosahexaenoic acid (17-HDHA) – a compound which is known to reduce pain.
They found this to be the case, but the increase in 17-HDHA levels was not statistically significant.
“Importantly, the study does not provide any evidence to show that dietary supplements of omega-3 fatty acid provide benefit,” said Dr Tom Sanders, a professor emeritus of nutrition and dietetics at King’s College London, who was not involved with the research.
“However, advice to eat moderate amounts (one to two servings a week) of salmon would be consistent with current healthy eating advice.”
Rob Music, the chief executive of The Migraine Trust, told The Telegraph: “This is an interesting study, although the numbers participating are relatively small.
“It would be good to see further and larger pieces of research into omega, as well as other dietary interventions for migraine, as The Migraine Trust does hear from some people that they find supplements and diet helpful with managing migraine.”