What do mustard, garlic and being cold all have in common? Not much, when you think about it, but there is one thing that ties the three together: pain receptors in the body.
As it turns out, researchers from Lund University in Sweden have identified the mechanism in the body that (in some people) makes feeling cold painful. Surprisingly, it is the same receptor that reacts to the pungent substances in mustard and garlic.
The research into this particular pain receptor has been on-going for a decade; Professor of Pharmacology Peter Zygmunt and Professor of Clinical Pharmacology Edward Högestätt are experts on the effects mustard and garlic have on the body, researching these two substances because of their inclusion in crowd-control devices like pepper spray and tear gas. Throughout their research they speculated that the same receptor that induces pain from spices was likely responsible for the painful sensations linked to cold allodynia, or a hyper-sensitivity to cold.
“We have worked with Professors of Biochemistry Urban Johanson and Per Kjellbom here in Lund to extract the human receptor protein and insert it into an artificial cell membrane. There we could see that it reacted to cold,” explained Peter Zygmunt in an adapted press release. “We already know that the chilli receptor not only reacts to chilli, but also to temperatures over 42°C, such as when you burn yourself on a fire. The menthol receptor reacts to temperatures under 28°C, which are perceived as pleasantly cooling. And now we know that the mustard and garlic receptor reacts to temperatures under 20°C.”
Cold allodynia may not seem like a common issue, but many people with other nervous system disorders develop the hyper-sensitivity to cold as a result of treatment of medications. Understanding which receptors in the body influence the link between pain and cold could eventually lead to a treatment for this condition.
“These problems are very common in patients with chronic pain or diseases that affect the nervous system, such as diabetic neropathy. Patients undergoing chemotherapy can also become over-sensitive to cold as a side-effect of their medication. The discomfort and pain experienced by patients can start at relatively mild temperatures, within the temperature span to which the mustard and garlic receptor reacts,” said Edward Högestätt.
SEE ALSO: Tricks to staying warm in cold weather
There are many forms of allodynia; the term itself means “other pain.” According to the Fred Sheftell MD Education Center, cold allodynia is considered a form of thermal allodynia. The severity can vary from person to person and is often linked to an increased frequency of migraine headaches. In the case of the new link between cold sensitivity and mustard/garlic receptors, researchers also feel individuals with this form of allodynia will have sensitivities to perfume, solvents, cigarette smoke, car exhaust, and other airway irritants.