Could the heat of some spices solve some of medicine’s biggest problems? (Image: Spencer Wilson)

Understanding why mint tastes cool and chilli is hot could bring new cures for chronic pain, obesity and even cancer

IT STARTS out as a pleasant tingle, before growing into a burning sensation that feels like your whole mouth is ablaze. You sweat, you cry, and your nose streams. You gasp for water, but it feels like nothing can douse the flames. Once the pain has subsided, however, you suspect you’ll seek out an even more extreme fix the next time around.

Anyone who enjoys a curry knows this feeling – and chefs have been using the sensation of chillies and other peppers to spice up their culinary experiments for centuries. But it is only in the last decade or so that scientists have begun to understand how we taste piquant foods. Now they have found the mechanism that not only explains the heat of chillies and wasabi, but also the soothing cooling of flavours like menthol.

The implications of this discovery extend far beyond cuisine. The same mechanisms build the body’s internal thermometer, and some animals even use them to see in the dark. Understand these pathways, and the humble chilli may open new avenues of research for conditions as diverse as chronic pain, obesity and cancer.

The story begins in earnest in 1997, with David Julius at the University of California, San Francisco. Although people had long speculated about the source of the chilli’s fire, his team was the first to discover how its key component, capsaicin, sets our mouth aflame. Most of …