<P> Lactase persistence is the continued activity of the lactase enzyme in adulthood . Since lactase 's only function is the digestion of lactose in milk , in most mammal species , the activity of the enzyme is dramatically reduced after weaning . In some human populations , though , lactase persistence has recently evolved as an adaptation to the consumption of nonhuman milk and dairy products beyond infancy . The majority of people around the world remain lactase nonpersistent , and consequently are affected by varying degrees of lactose intolerance as adults . However , not all genetically lactase nonpersistent individuals are noticeably lactose intolerant , and not all lactose intolerant individuals have the lactase nonpersistence genotype . </P>
<P> Lactase persistence is the continued activity of the lactase enzyme in adulthood . Since lactase 's only function is the digestion of lactose in milk , in most mammal species , the activity of the enzyme is dramatically reduced after weaning . In some human populations , though , lactase persistence has recently evolved as an adaptation to the consumption of nonhuman milk and dairy products beyond infancy . The majority of people around the world remain lactase nonpersistent , and consequently are affected by varying degrees of lactose intolerance as adults . However , not all genetically lactase nonpersistent individuals are noticeably lactose intolerant , and not all lactose intolerant individuals have the lactase nonpersistence genotype . </P>
when do most mammals lose their ability to produce lactase
when do most mammals lose their ability to produce lactase
after weaning
after weaning