I've heard that all people are lactose intolerant to some degree, because our bodies aren't built to digest the milk of other animals.
Lactose intolerance
Lactose intolerance is a condition in which people have symptoms due to the decreased ability to digest lactose, a sugar found in dairy products. Those affected vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pain, bloating, diarrhea, gas, and nausea. These symptoms typically start thirty minutes to two hours after eating or drinking milk-based food. Severity typically depends on the amount a person eats or drinks. Lactose intolerance does not cause damage to the gastrointestinal tract.
managed by ingesting live yogurt cultures containing lactobacilli that are able to digest the lactose in other dairy products. This may explain why many South Asians, though genetically lactose intolerant, are able to consume large quantities of milk without many symptoms of lactose intolerance, since consuming live yogurt cultures is very common among the South Asian population.
Epidemiology.
Overall, about 65% of people experience some form of lactose intolerance as they age past infancy, but there are significant differences between populations and regions, with rates as low as