It looks like a trinket a tourist might pick up as a quaint souvenir, but this fish has the power to cure anemia.

Called the Lucky Iron Fish, the three-inch-long piece of metal functions like a nutritional supplement, only instead of swallowing it, you add it to a simmering pot of food for ten minutes. Doing that can increase the iron content in the diets of users in places like Cambodia, where roughly half of the population suffered from iron-deficiency anemia before Lucky Iron Fish was introduced. The fish just won this year’s Cannes Lion Grand Prix in product design.

That an analog device could top out a product design category filled with future-facing technology—like a DNA-sequencing food testing kit and a gamified studio cycling bike—speaks to both its effectiveness and its genius. The designers not only managed to make the treatment foolproof but increased compliance by hacking a local superstition, that fish are auspicious.

The Lucky Iron Fish

Christopher Charles, an epidemiologist, was living in Cambodia in 2008 when he witnessed firsthand the societal effects of anemia. The condition, in which the blood stream doesn’t have enough healthy red blood cells to pump oxygen throughout the body, can lead to extreme lethargy, dizziness, and birthing complications. It’s caused by insufficient amounts of iron in the body. Iron is easy enough to get through certain foods or supplements, but neither were an option in rural Cambodia, where the local diet consists primarily of fish and rice.

Charles happened to know of a simple, cheap solution: adding a chunk of iron metal to food while it cooks. The heat causes the blocks to release between 60 and 300 milligrams of bioavailable iron, which then gets absorbed into the food or water. That’s substantially more than is recommended for one person a day, so you can imagine the iron’s effectiveness at improving an entire family’s diet at once. Problem was, nobody wanted to use it. It was ugly and unappetizing. It looked like it would ruin a meal. When Charles and his newly formed Lucky Iron Fish partners started troubleshooting, they came across a funny insight into Cambodian culture: the kantrop fish, a staple in the local diet, was also a good-luck symbol. So they started carving the small bricks of iron into little kantrop fish instead. It worked: Women—who do most of the cooking—started slipping them into pots and skillets. There are currently 5,000 of them being used in kitchens across the country.

Lucky Iron Fish is in its third round of trials now, and so far, has found evidence linking adoption of the fish to a 50 percent decline in iron-deficiency anemia in the areas they’re being used. It’s also a fairly long-term, easily scalable solution: The fish, which are mostly made from recycled car parts, work for up to five years. And the Lucky Iron Fish Project is only getting bigger: The organization has 12,000 fish in the pipeline to be distributed, and is looking into expanding to other Southeast Asian countries, India, and East Africa. In those parts of the world, the fish could take on other culturally relevant forms.