Why is lactose tolerance also called lactase persistence?

Lactose tolerance is referred to as lactase persistence because it describes the continued production of lactase, the enzyme that breaks down lactose, into adulthood. In many mammals, lactase production decreases after weaning, leading to lactose intolerance. However, in certain human populations, genetic adaptations allow for sustained lactase production, enabling these individuals to digest lactose throughout their lives. This genetic trait is termed lactase persistence, highlighting the ongoing ability to process lactose effectively.