'It's going to be the new little wave' For decades, if not centuries, the Amazon dwellers of southern Colombia didn’t make too much of the cacay nut. They fed it to their livestock, used it to treat wounds and chopped down its trees for firewood. But then, a few years ago, the global jet-setting crowd found out what the yellow-ish oil from the protein-rich nut could do for their skin. And suddenly, the cacay (pronounced kahk-ai) has become a red-hot commodity, providing the key ingredient to anti-aging facial creams that can fetch $200 an ounce in beauty shops in Los...