The saying goes that redheads have more fun — but the opposite is actually true. Not that redheads have less fun, but rather, redheads feel more pain. At least, a different kind of pain.
Red hair occurs naturally in 1-2% of the human population, and it’s safe to say the world is fascinated with it. To say that redheads have their own charm would be an understatement, but this was also a downside at times. During the Dark Ages, gingers were often considered witches or heretics. It’s not clear why we’re so fascinated by them, but our fascination is just about to go even deeper: due to their different genetic makeup, redheads require more anesthesia, are more prone to certain diseases, and experience pain differently.
Making a redhead
Red hair is commonly — to a relative extent — found in the northern and western parts of Europe, especially in and around the British Isles. In Ireland, for instance, the population with red hair is estimated to be at around 10%, whereas in Scotland, around 6% of all people can boast that color. Still, even so, red is, by a wide margin, the rarest natural hair color.
Genetic studies have shown that a protein–coupled receptor called MC1R holds the key for this mutation. A few alleles (Arg151Cys, Arg160Trp, Asp294His, and Arg142His) are recessive for the red hair phenotype. Similar studies have shown that some Neanderthals were redheads too, but this doesn’t mean that redheads have Neanderthal ancestors — scientists believe the mutation emerged differently than in humans.
Contrary to a popular belief, redheads are not disappearing. A 2007 report in The Courier-Mail, which cited a National Geographic article and unnamed geneticists turned viral and became extremely popular. Many other websites picked up a similar story, quoting a study published in a magazine by the “Oxford Hair Foundation”. Well, turns out that the article was funded by hair-dye maker Procter & Gamble and was extremely lacking in substance; in other words, in was more a marketing stunt than a serious article. The initial National Geographic article actually stated that “while redheads may decline, the potential for red isn’t going away.” But back to our genetic makeup.
We know that at least some (probably most) of the genetic differences in redheads are associated with MC1R. Like most other cell surface receptors, MC1R is regulated by a set of complementary proteins. In 98% of the population, MC1R produces dark eumelanin, a dark type of pigment. But in redheads, the mutation to MC1R leads to the production of a red pheomelanin — this is the pigment that gives the specific hair color. But it gets even more interesting.
The same mechanism that causes this red-tinged pigment also stimulates some hormones, including those called endorphins. Endorphins are secreted within the brain and nervous system and they have a whole bunch physiological functions — but they’re most famous for providing pain relief and making you feel some pleasure. Today, many geneticists are confident that the MC1R gene is directly related to pain.
A different kind of pain
An increasing number of studies has shown that these interactions make redheads feel pain differently and have different body reactions. For instance, one study found that people with red hair are more sensitive to thermal pain, while another showed that they are less sensitive to a wide array of painful stimuli, such as electrically induced pain. So it’s not as simple as saying that redheads are more or less tolerant to pain — they just tend to feel pain differently. To make it even more intriguing, research has also shown that redheads require more anesthetic. Overall, they’re tougher than pretty much all other hair colors.
They’re also more resistant to spicy foods, showing less sensitivity to capsaicin, the active component of chili peppers
“Our tests showed that redheads are less sensitive to this particular type of pain. They react less to pressure close to the injected area, or to a pinprick. They seem to be a bit better protected, and that is a really interesting finding,” says Professor Lars Arendt-Nielsen of the Center for Sensory-Motor Interaction at Aalborg University.
However, redheads also turned out to be more vulnerable to toothaches, and more afraid of the dentist (presumably due to the stronger pain they feel). Even more disturbingly, their genes make them more likely to suffer from several diseases, such as sclerosis.
So, to sum up several studies, redheads:
- are more vulnerable to extreme temperatures, especially cold;
- are less responsive to anesthetic;
- are less vulnerable to various types of pain, including electrical shocks;
- are less responsive to spicy foods;
- are more afraid of the dentist, and feel toothaches stronger;
- are at a greater risk of diseases such as sclerosis and endometriosis.
A widely believed myth claimed that redheads were more likely to bleed heavier, up to the point where some surgeons refused to carry out complicated surgeries, due to a fear of excessive bleeding. Well,
Tougher than others
So, we do know that the same variants that give redheads their distinctive hair hue have significant other effects, especially on how they feel pain, but also on a predisposition towards certain diseases. Animal studies seem to indicate that redheads may react better to some drugs, and worse to others, than the general population. Hopefully, future studies can help us better understand these genetic differences, and help us tailor better custom treatments.
“It seems that MC1R is involved in central functions in the brain, and we know that subgroups like MC2R, MC3R and MC4R, which are also linked to redheads, have considerable involvement in brain functions. This could be the key to explaining why redheads are a little different to other people,” says Arendt-Nielsen.
For now, let’s just keep in mind that redheads are a bit different than most people. They’re certainly not witches, and they’re often tougher than the rest of us — but sometimes, they’re also more vulnerable.