Beriberi is a serious disease caused by not getting enough vitamin B1, also called thiamine. Your body needs thiamine to turn food into energy and keep your nerves working properly. Without it, muscles weaken, nerves stop functioning correctly, and the heart can struggle to pump blood.

For thousands of years, beriberi affected people in Asia whose diets consisted mainly of polished white rice, which has had its outer layers removed along with most of its thiamine. In the late 1800s, a Dutch doctor named Christiaan Eijkman discovered that chickens fed only polished rice developed symptoms like beriberi, while chickens eating brown rice stayed healthy. This breakthrough helped scientists understand that food contains essential nutrients our bodies need to stay healthy.

Today, beriberi is rare in countries where people eat varied diets with whole grains, meat, and fortified foods. But it still appears in places where people don't have access to nutritious food, or in people with conditions that prevent their bodies from absorbing thiamine properly.