Migraines have long thought to be caused by fluctuations in the chemicals of the brain - specifically when the level of serotonin decreases.
But as no one really knows why the level of serotonin is decreasing, a new study has shed light on another possibility - people who get migraines may have differences in the blood vessel structure of their brains.
"These differences seem to be associated with changes in blood flow in the brain, and it's possible that these changes may trigger migraine, which may explain why some people, for instance, notice that dehydration triggers their headaches," study researcher Dr. Brett Cucchiara, MD, associate professor of neurology at the University of Pennsylvania Perelman School of Medicine, explained in a statement.
Over 8 million people in the UK suffer from migraines, and the low levels of serotonin can make blood vessels in one part of your brain suddenly contract, which makes them narrower. The NHS adds: "Soon after the blood vessels dilate, which is thought to cause the headache."
There are several ways to raise serotonin - reducing stress, exercise and being in direct sunlight are three - but you can make an immediate start with your diet.
Avoid white sugar and simple carbs (white bread, pasta and rice) as these will raise your blood sugar and then send it crashing down. Make sure you're also eating plenty of protein. Chatelaine.com says: "The production of serotonin is closely linked to the availability of vitamin B6 and the amino acid tryptophan. If our diet lacks sufficient protein and vitamins, we run a greater risk of serotonin deficiency."
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The new study, published in the journal PLOS ONE, included 170 people who fit into one of three categories: those who didn't get any migraines, those who got them with aura, and those who got them without aura. Researchers looked at the structure of blood vessels in the study participants' brains, as well as changes in cerebral blood flow. They specifically looked at the "circle of Willis," which is the term used for a system of arteries responsible for delivering blood to the brain.
The researchers found that people with migraines were more likely to have an "incomplete" circle of Willis than those who didn't get migraine headaches. Specifically, 73 percent of those who get migraines with aura had an incomplete circle of Willis, and 67 percent of those who get migraines without aura had an incomplete circle of Willis. Meanwhile, 51 percent of those who didn't get migraines had an incomplete circle of Willis.
MIGRAINE FACTS:
- In the UK, there are an estimated 190,000 migraine attacks every day (Steiner et al, Cephalalgia, 2003)
- Women are more likely to have migraine attacks than men – 18% of women and 8% of men (Steiner et al, Cephalalgia, 2003)
- Among adults of all ages, migraine is one of the top 20 causes of disability expressed as years of healthy life lost to disability (The World Health Report 2001, WHO)
Source: Migraine Trust
"Abnormalities in both the circle of Willis and blood flow were most prominent in the back of the brain, where the visual cortex is located. This may help explain why the most common migraine auras consist of visual symptoms such as seeing distortions, spots, or wavy lines," senior author of the study, Dr. John Detre, MD, a professor of neurology and radiology at the university, said in a statement.