The Journal of the American Dental Association recently published new research revealing that redheads are in fact impervious to local anesthetics. This explains why redheads are more wary of doctors and dentists than patients with other hair colors.
The research proposes that the phenomenon is a result of a mutation in the same gene that dictates hair color. The gene leads to melatonin production in people with blond, brown and black hair, but the redhead mutation in the MC1R gene makes a substance called pheomelanin instead. This leads to the red hair and the characteristically fair skin.
This is not the first study to address the issue. In 2004, a project revealed that redheads rProfequire an average of 20% more general anesthesia than other patients. A study in 2005 showed similar results.
The MC1R gene is part of a group of receptors responsible for pain comprehension in the brain. As a result, the mutation amplifies the body’s pain sensitivity. The mutation can sometimes be found in people of other hair colors, though not often. The latest research showed that 65 of 67 redheads had the MC1R gene variant, as opposed to 20 of 77 brunettes.
The study also mapped the participants’ anxiety and fear of the dentist, and found that those with the MC1R mutation were remarkably more wary of the dentist, and more than doubly likely to avoid any sort of dental care.
Dr. Daniel I. Sessler of the study said “The reason we studied redheads in the beginning, it was essentially an urban legend in the anesthesia community saying redheads were difficult to anesthetize. This was so intriguing we went ahead and studied it. Redheads really do require more anesthesia, and by a clinically important amount.”
He added, “Because they’re resistant, many redheads have had bad experiences. If they go to the dentist or have a cut sutured, they’ll need more local anesthetic than other people.”
Other recent studies have revealed that although redheads are more sensitive to certain pains and more immune to anesthetics, their skin is tougher than that of other people. In fact, they are less susceptible to skin-related pain.
Professor Lars Arendt-Nielsen explained: “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.”
Redheads are also less sensitive to hot and spicy foods, and more sensitive to the cold.