Chinese researchers believe they have shown that selenium protects against liver cancer. In a study comparing two towns containing together 130,000 people, they supplied table salt enhanced with 15 parts per million sodium selenite to one town and unsupplemented table salt to the other.

After eight years, the incidence of liver cancer in the two towns was compared. The town using selenium-enriched salt had half the number of cases (27 per 100,000 as opposed to 50 per 100,000).