A shiny, pinkish-brown triangle tucked under the right rib cage, a healthy liver is a marvel. Nutrient-rich blood from the intestines pulses into one side, and the liver goes to work removing toxins, converting digested food to energy, storing vitamins and minerals, and controlling how much fat and sugar is sent back out to the rest of the body.

Without the liver acting as a filter and energy producer, a person can’t survive, and no artificial organ can perform all of its duties. But in one in three Americans—and similar numbers in other developed nations—the liver has lost its luster. It is swollen, yellowish, congested with fat, and doesn’t function up to par. Over time, this condition, called fatty liver disease, can lead to inflammation, scarring, and hardening of the organ, and eventually, liver failure. In some people, it causes liver cancer.

Illustration: Graham Roumieu