Nicotine. Caffeine. Betel nuts. You may never have heard of them, but nuts from the Areca palm are hugely popular as a chewable stimulant: Almost a tenth of the global population enjoys them, the BBC reports. A millennia-old tradition, they're the world's fourth-most-popular psychoactive substance, Healthline adds. Their effect is similar to that of drinking six cups of coffee, and many workers engaged in lengthy physical tasks chew them to maintain alertness. Trouble is, they're incredibly dangerous. Potentially leading to oral cancer and terrible mouth lesions, they're likely responsible for tens of thousands of early deaths, the BBC notes. In Taiwan, about 5,400 men receive oral cancer diagnoses each year; as many as 90% of them are betel nut chewers.
The situation is only made worse by the way betel nuts are often packaged: in what are called quids, which can be made using known carcinogens like tobacco and slaked lime. The latter can generate small abrasions in the mouth that may help the carcinogens get into the body. Despite the dangers, betel nuts are called "Taiwan's chewing gum," and about half the country's men aren't aware of the cancer issue, an expert says—even as people like Qiu Zhen-huang develop holes in their cheeks. Decades after he quit the stuff, he ended up with a golf ball-sized tumor. The FDA doesn't consider betel nuts safe, Healthline notes, and in recent years, Taiwan has been fighting their use—though it remains legal, Shanghaiist reports. Free screenings and other programs helped cut men's chewing rates in half two years ago, the BBC notes. (As for smoking: Keep doing it, and there's a 67% chance you'll die from it, a study finds.)