Final answer:
Lactose intolerance is the digestive issue that inhibits the ability of many adult mammals to digest milk due to reduced lactase production. This condition can cause symptoms like bloating and cramps, but lactose-free options and supplements can help manage the problem.
Step-by-step explanation:
The digestive issue that causes many mammals to become ill if they drink milk as adults, even though they could consume it as babies, is lactose intolerance. This condition is the result of an inability to produce enough lactase, the enzyme needed to metabolize lactose, the sugar found in milk. In the case of adult mammals, including some human populations, the production of lactase typically decreases with age, leading to a higher incidence of lactose intolerance. However, certain human populations, particularly in Europe, have developed a genetic tolerance to lactose due to evolutionary factors related to dairy agriculture and the need for vitamin D absorption.
Infants with an inborn deficiency in lactase are intolerant to milk and may exhibit symptoms such as diarrhea and vomiting, necessitating the use of lactose-free formulas. While lactose intolerance is common among Asian adults, it also affects a significant portion of people worldwide to varying degrees. People with lactose intolerance may experience symptoms like bloating, cramps, and nausea when consuming dairy. Options such as lactose-free milk or lactase supplements can allow individuals to enjoy dairy products without discomfort.