Why evolution gave us migraine

Our genes can also make us more likely to develop certain medical conditions. Migraine is one of them. If a person has a tendency to get migraines, this is because it’s written into their DNA. Researchers are interested in how migraine became part of our genetic makeup in the first place. Another interesting question is why it has remained there through many generations, even though it is definitely a disadvantage today. Why wasn’t the tendency to develop migraine gradually removed from the human gene pool during evolution? If it had been, many people today might be living without migraine and the suffering it brings.

Our ancestors moved north from “the cradle of humankind”

Large population studies have shown that migraine is more common in northern regions such as Europe and North America than in warmer parts of the world. Scientists have recently suggested an interesting explanation for this. It may be linked to the fact that our ancestors left their homelands in Africa and moved north to settle in new areas.

Over the last 50,000 years, many groups of people migrated from the warm regions of Africa and Asia to colder regions further north. Many eventually settled in Europe and North America. Life in these new regions was often more difficult, especially because of the cold winters. The migrants brought one thing with them wherever they went: their DNA. Scientists now believe that, as humans spread northwards, gradual changes in their genes helped them adapt to colder temperatures and harsher environments.

TRPM8: a major advantage in cold environments

Scientists from the Max Planck Institute for Evolutionary Anthropology in Leipzig were among the researchers involved in studies that uncovered this link. They focused on a specific section of human DNA. This particular section (i.e., gene) is called TRPM8, which stands for “transient receptor potential melastatin 8”. TRPM8 contains the instructions for producing and regulating a “cold receptor”, which acts like a tiny thermometer in the skin, detecting when things are cold and helping to control our body temperature. People who carry this genetic trait are better able to cope with cooler temperatures. Anyone with TRPM8 would have found it much easier to settle in colder regions far from humanity’s African origins. This greatly helped humans spread and settle across different parts of the world. In the words of Aida Andres from the Max Planck Institute, “The settlement of new habitats in Europe and Asia may have been linked to genetic changes that helped early humans adapt to lower temperatures.”

The “cold gene” becomes more common

The researchers in Leipzig found that a particular form of the TRPM8 gene has spread very successfully over the last 25,000 years. The further north people live, the more common this version of the gene becomes. For example, only about 5% of people with Nigerian ancestry carry this genetic variant. The average annual temperature in Nigeria is around 28°C. In contrast, the variant is found in as many as 88% of people with Finnish ancestry, where the average annual temperature is about 6°C.

One gene, two effects

Researchers have also linked this northern variant of the gene to migraine headaches. More than one billion people worldwide live with migraine. The same geographical differences apply here, with migraine being more common in Europe and the USA than in Africa or Asia. Studies have also shown that Americans of European ancestry have a higher risk of migraine than African Americans.

Researchers currently believe that this newer form of the gene developed from an older version that is still common in Africa today. This change is likely to have occurred over the past 25,000 years. This supports the idea that genetic adaptations to cold temperatures in early human populations may still influence how common migraine is in different parts of the world today.

Does the evolutionary trade-off still make sense?

As early humans moved north, evolutionary pressure must have been intense. Being able to survive increasingly cold conditions became essential. The cold-adaptation gene that is linked to migraine became an important survival advantage. From an evolutionary point of view, the ability to live in cold environments was far more important than the disadvantage of being more likely to develop migraine attacks.

Today, however, the balance between these advantages and disadvantages has changed, and may even have reversed. Unlike our ancestors, we have heated buildings, warm clothing, and many other ways to protect ourselves from the cold. As a result, the body’s natural ability to tolerate cold temperatures has become less important. At the same time, the burden caused by migraine has become more significant. Modern life, especially in so-called Western countries, also includes many factors that may trigger migraine attacks. This means that a genetic tendency towards migraine may lead to severe migraine headaches more often today than it did under the living conditions of our distant ancestors.

The future of migraine research

Scientists still do not know exactly why there is a connection between the ability to sense cold and a tendency to develop migraine. There is some evidence that the TRPM8 receptor may play a role in the perception of cold-related pain and possibly other types of pain as well. However, there is still much to learn in this area.

One thing is certain: until evolution frees us from our inherited tendency towards migraine, people will have to find ways to live with it. Unfortunately, we cannot simply switch off our susceptibility to migraine attacks. That is why it is so important to understand how migraine develops and which factors in everyday life may trigger attacks. This knowledge allows people with migraine to make gradual changes to their daily routines and reduce their personal risk of attacks. In this way, patients can become experts in managing their own condition and take a more active role in controlling their headaches. This is likely to be far more helpful than simply hoping that evolution will one day solve the problem for future generations.