Diets high in fatty fish and low in vegetable oils reduce headaches in adults with migraines, a new study suggests.
In the randomised controlled study (NCT02012790), participants eating diets rich in pain-reducing omega-3 fats from fatty fish with minimal pain-promoting omega-6 fats from vegetable oils had significantly fewer headaches than people eating diets limited in fatty fish and rich in vegetable oils.
The study, “Dietary alterations of n-3 and n-6 fatty acids for headache reduction in adults with migraines: randomised controlled trial,” was published in The BMJ.
Migraines are recurrent headaches that affect up to 20% of the population, mainly between the ages of 22 and 55 years. It typically starts in childhood, particularly around puberty, and affects women more than men. Migraines tend to run in families and is considered a genetic disorder. Advances in research have led to the development of advanced migraine therapies. But despite using multiple, effective drugs, many people still experience severe pain and debilitating migraines.
Essential omega-3 and 6 fats are only available from food, the body cannot produce them. Omega-3 fats are present in fatty fish as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), while omega-6 fats are present as linoleic acid in vegetable oils.
Once obtained through diet, these essential fats enter tissues that influence migraine development, serving as building blocks for proteins – called oxylipins – that control pain.
Oxylipins made from linoleic promote pain, while those from EPA and DHA reduce pain. For example, 17-hydroxydocosahexaenoic acid (17-HDHA) – a DHA-derived oxylipin – has shown strong pain-reducing effects in people with arthritis.
Earlier studies have shown that manipulating the essential fat content of a person’s diet can alter the oxylipins present in tissues associated with migraine headaches. And recent studies show that increasing EPA and DHA intake while decreasing linoleic acid intake reduces the number of headaches that people with migraines experience. However, it is unclear if increasing EPA and DHA without reducing linoleic acid is enough to reduce migraines.
A team of researchers at the University of North Carolina at Chapel Hill now sought to investigate whether increasing EPA and DHA intake alone was sufficient to reduce headaches in people with migraines.
A total of 182 participants were randomised to receive one of three dietitian-formulated diets for 16 weeks: high omega-3 (H3), high omega-3 with low omega-6 (H3-L6) or a control diet containing the average amounts of omega 3 and 6 in adult diets in the United States.
All three diets were designed to be as similar as possible, the only difference being the amount of omega 3 fats and omega-6 fats. The H3 and H3-L6 diets contained 1.5 g/day of EPA+DHA omega 3 fats derived from fatty fish, while the control diet contained the average US intakes of <150mg/day derived from low-fat fish or poultry.
The H3 and control diets contained the average US omega-6 intake (7.2% of energy), provided via a blend of corn oil and extra virgin olive oil and a mixture of butter and corn oil. The H3-L6 diet was designed to contain up to 1.8% of energy from omega-6 fats, derived from a combination of macadamia nut oil and extra virgin olive oil and regular butter.
After 16 weeks on the diets, the researchers measured the number of monthly and daily headaches the participants had with an electronic headache diary, the number of medications they used and the levels of 17-HDHA in their blood. They also measured the impact headaches had on the participants’ ability to function at work, school, home, and social settings using a self-reported six-item questionnaire called the headache impact test (HIT-6).
Of the initial 182, a total of 141 participants completed the 16-week study. The average baseline HIT-6 score was 62.7, indicating a severe impact of headaches on quality of life (QoL). Participants also had an average of 16.3 headache days monthly, 5.4 headache hours daily and used 4.3 drugs.
After 16 weeks, HIT-6 scores improved in the H3 and H3-L6 groups, and while clinically meaningful, they did not reach statistical significance. However, the average number of daily headache hours significantly was reduced to 3.6 and 3.2 in the H3 and H3-L6 groups, respectively.
The H3-L6 group had four fewer headache days per month compared with the control group and two fewer headache days per month compared with the H3 group, suggesting “additional benefit from lowering dietary omega-6.” In fact, “participants with lower omega-6 concentrations in blood had fewer headaches at the end of the study.”
Interestingly, the daily and monthly headache reductions participants in the H3-L6 group achieved were similar to botulinum toxin injections or antibodies targeting migraine-associated proteins. Also suggesting that diet could be an effective “adjunct approach for managing headaches.”
“This research found intriguing evidence that dietary changes have potential for improving a very debilitating chronic pain condition such as migraine without the related downsides of often prescribed medications,” Luigi Ferruci, MD, PhD, Scientific Director of National Institute of Aging said.
Compared with the control diet, both H3 and H3-L6 diets decreased non-steroidal anti-inflammatory drugs (NSAIDs) and aspirin use and increased the amounts of DHA-derived pain-reducing oxylipins such as 17-HDHA. Increases in DHA-derived oxylipins were linked to lower daily headache hours. However, neither diet reduced the quantities of pain-promoting oxylipins or migraine-associated proteins.
Study limitations, the researchers wrote included investigating changes in HIT-6 instead of headache diary data as the primary research question, a study population comprised of women and not assessing metrics that may be more directly involved in headache development.
Still, the researchers concluded by writing “we tested two active dietary interventions designed to target biochemical mechanisms known to regulate nociception (pain). Both diets produced biochemical changes consistent with decreased nociception. 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 H3-L6 diet was more effective than the H3 diet for some outcomes.”
Further studies should test the diets in other populations with chronic pain and should evaluate “whether decreasing dietary linoleic acid to lower levels or administering the interventions for longer duration would result in great pain reduction because turnover of polyunsaturated fatty acids in relevant tissues could take years,” they added.
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