Why people who get migraines may want to eat more fatty fish

For most of her life, Tanya Kamka suffered migraine headaches on a weekly basis.

The headaches would usually come on gradually and then build, causing excruciating pain and pressure behind her left eye that would culminate in her vomiting or visiting the emergency room. The ordeal would often leave her feeling weak and exhausted for days afterward.

"Anytime I had a migraine I'd be wiped out for three or four days," said Ms. Kamka, 58, a post office clerk who lives near Fort Bragg, N.C. "I missed a lot of work because of migraines."

But a few years ago, Ms. Kamka and 181 other people who routinely experience migraine headaches joined a clinical trial, sponsored by the National Institutes of Health, which was designed to test whether a special diet could alleviate their frequent headaches. The diet that Ms. Kamka was assigned to follow emphasized foods that contain large amounts of omega-3 fatty acids, the oils found in some fish, while limiting foods that are rich sources of omega-6 fatty acids, such as many vegetable oils.

Omega-3s and omega-6s are both considered essential fatty acids — critical for health, and because our bodies can't make them, they must be obtained from foods. Historically humans consumed roughly equivalent amounts of both fatty acids. But the typical American diet today tends to contain a much larger proportion of omega-6 fats. Some health authorities see this as a good thing: Vegetable oils and other rich sources of omega-6 fats have been found in many studies to be beneficial for cardiovascular health. But others argue that this could be problematic because omega-6 fats have been shown to promote pain and inflammation, while omega-3 fats tend to have the opposite effect in studies, helping to reduce pain and inflammation.

The authors of the new study wanted to know: Could a diet that boosts omega-3 fats while lowering omega-6 fats make life easier for people burdened by frequent migraine headaches?

For Ms. Kamka, the benefits of a change in diet were striking: After a few months of increasing her fish intake and avoiding many common vegetable oils, she noticed that her headaches had all but disappeared. Other people on the new diet also reported fewer headaches. Although the trial ended after 16 weeks, Ms. Kamka has remained on it ever since. Gone are the days when she ate foods like fried chicken, French fries and potato chips that were cooked in vegetables oils rich in omega-6 fats. She now makes a point of eating foods like cod, tuna, sardines, spinach salads, hummus and avocados, and she cooks with olive oil instead of corn, soybean and canola oils.

"I haven't had a migraine, not even a mild one, in over two years," she said. "Going from having one a week to not having any was just amazing to me."

Migraine headaches are one of the most common causes of chronic pain, affecting about 12 percent of all Americans, most of them women. For many people, the condition can be debilitating, causing intense pain, nausea and other symptoms and sharply increasing the likelihood of developing depression and anxiety. Studies have found that migraine attacks can take a toll on workplace productivity, too, causing people to lose, on average, about four work days per year.

But the new study provides evidence that the right diet could provide relief to some people who experience frequent migraine attacks, helping them reduce the number and severity of their headaches. Similar studies are underway to assess whether dietary changes could help ease other kinds of painful chronic ailments, such as low back pain.

Dr. Christopher E. Ramsden, the lead author of the study, said the findings suggest that dietary changes could be a useful complement to existing treatments for chronic pain. "Many people with chronic pain continue to suffer despite taking medication," said Dr. Ramsden, a clinical investigator in the National Institute on Aging Intramural Research Program. "I think this is something that could be integrated with other treatments to enhance their quality of life and reduce their pain."

For the new trial, published in the BMJ in July, participants were randomly split into three groups and followed for 16 weeks. One group, which included Ms. Kamka, followed a diet that was high in omega-3 fats and relatively low in omega-6 fats: They ate plenty of foods like wild salmon, albacore tuna and trout, while trying to minimize rich sources of omega-6 fats such as corn, soybean and canola oils. To make it easier to follow the diet, all of the subjects were given meals, snacks and recipes prepared by a dietitian throughout the course of the study.

Vegetable oils high in omega-6s are abundant in the American diet. They are often used for cooking and found in many packaged foods and restaurant meals. To see whether reducing these fats could have an impact on migraine headaches, the researchers had a second group of people add more fish and other rich sources of omega-3s to their diets without decreasing their intake of omega-6s. A third group of people, serving as controls, consumed typical amounts of both types of fats.

At the start of the study, the participants experienced, on average, about 16 "headache days" per month. But after 16 weeks, the group that had increased their fish intake and avoided vegetable oils had an average of four fewer "headache days" each month compared to the control group, as well as a 30 to 40 percent reduction in "headache hours" each day. The group that increased their omega-3 intake without reducing their omega-6 consumption benefited as well, though they had a smaller improvement of two fewer days without headaches each month. Both of these groups reported shorter and less severe headaches than people in the control group. They also used fewer pain relievers like acetaminophen.

The researchers also noticed differences in important blood biomarkers. The two groups that increased their fish intake had greater levels of compounds known as oxylipins, which are involved in soothing pain. They had particularly high levels of 17-HDHA, an oxylipin that in other studies has been shown to reduce pain in people with arthritis.

Dr. Rebecca Burch, a neurologist who was not involved in the new study, said that the findings were striking. She wrote an editorial in the BMJ pointing out that recently approved migraine medications have been shown in studies to produce two to two and a half fewer "headache days" per month compared to placebo, which is less than the four-day reduction caused by the high omega-3, low omega-6 diet.

"Four days per month really outperforms anything we've seen from a pharmacological preventive," said Dr. Burch, a headache medicine specialist at Brigham and Women's Hospital and an assistant professor of neurology at Harvard Medical School.

Dr. Burch said that people who struggle with migraine headaches are often motivated to follow restrictive diets to try to find some relief for their condition. But until now there has not been much evidence that any particular diet works. "This is the first time that we've had a robust, solid diet that we can recommend to patients," she added.

For people who want to try the diet on their own, the researchers said that the simplest way to increase omega-3 intake is to eat more fatty fish, such as sardines, anchovies, mackerel, salmon, albacore tuna and trout. Some of the best and most affordable options are canned and pouched fish. For vegetarians, good plant sources of omega-3 fats are ground flaxseeds, chia seeds and walnuts.

Another important component of the diet is avoiding fried, processed and fast foods, which are typically made with oils that are low in omega-3s and high in omega-6s. Beth MacIntosh, a co-author of the new study, said that extra virgin olive oil, avocado oil, macadamia oil, coconut oil and butter tend to contain low amounts of omega-6 fats.

You can use these oils to cook meals or to make your own snack foods, like popcorn, hummus and granola. The researchers also encouraged people in the study to eat at least five servings of fruits and vegetables per day.

"Fruits and vegetables are naturally low in omega-6 fatty acids — and they're just healthy," said Ms. MacIntosh, the clinical nutrition manager of the Metabolic & Nutrition Research Core at UNC Health in Chapel Hill.