The cool science of hot peppers
Shiny green slices of jalapeño pepper adorn a plate of nachos. Chomping into one of those innocent-looking chilies will make a person’s mouth explode with spicy fireworks. Some people dread and avoid the painful, eye-watering, mouth-searing sensation. Others love the burn.
“A quarter of the world’s population eats chilies every day,” notes Joshua Tewksbury. He is a biologist who spent 10 years studying wild chili peppers. He also happens to enjoy eating hot, spicy food.
Chili peppers do much more than burn people’s mouths. Scientists have discovered many uses for the chemical that gives these veggies their zing. Called capsaicin (Kap-SAY-ih-sin), it’s the main ingredient in pepper spray. Some people use this weapon for self-defense. The spray's high levels of capsaicin will burn the eyes and throats of attackers — but won’t kill people. In smaller doses, capsaicin can relieve pain, help with weight loss and possibly affect microbes in the gut to keep people healthier. Now how cool is that?
A taste for spice
Why would anyone willingly eat something that causes pain? Capsaicin triggers a rush of stress hormones. These will make the skin redden and sweat. It can also make someone feel jittery or energized. Some people enjoy this feeling. But there is another reason why chilies show up on dinner plates the world over. Hot peppers actually make food safer to eat.
When food sits out in warm weather, microbes on the food start to multiply. If people eat food with too many of these germs, they risk getting very sick. The cold temperature inside a refrigerator stops most microbes from growing. That’s why most people today rely on refrigerators to keep their food fresh. But long ago, those appliances weren’t available. Chilies were. Their capsaicin and other chemicals, it turns out, can slow or stop microbial growth. (Garlic, onion and many other cooking spices can, too.)
Before refrigerators, people living in most hot parts of the world developed a taste for spicy foods. Examples include hot Indian curries and fiery Mexican tamales. This preference emerged over time. The people who first added hot peppers to their recipes probably had no idea chilies could make their food safer; they just liked the stuff. But people who ate the spicy food tended to get sick less often. In time, these people would be more likely to raise healthy families. This led to populations of hot-spice lovers. People who came from cold parts of the world tended to stick with blander recipes. They didn’t need those spices to keep their food safe.