Final answer:
Some people developed lactose tolerance due to a genetic mutation that provided an evolutionary advantage, particularly in Europe, where dairy products are a significant source of vitamin D. Adaptation to a dairy-rich diet is indicated by the continued production of lactase and changes in gut microbiota, affecting regional dietary preferences and health.
Step-by-step explanation:
Evolution of Lactose Tolerance
Some groups of people developed the ability to keep digesting milk into adulthood due to a genetic mutation that conferred lactose tolerance. This mutation had an evolutionary advantage, particularly in regions where vitamin D is less available from sunlight, as dairy products can be a significant source of this vitamin. The domestication of cattle and the onset of an agricultural lifestyle have played key roles in the prevalence of lactose tolerance, as certain populations adapted to the consumption of cow's milk. This adaptation is linked to the continued production of lactase, the enzyme necessary for lactose metabolism, beyond early childhood when most mammals typically stop producing it.
Moreover, lactose tolerance can also be attributed to prebiotic adaptation caused by changes in gut microbiota after the consumption of dairy foods, which provides a valuable source of calcium, proteins, and vitamin D. Fermentation processes utilized in cheese and yogurt production also allow those with lactose intolerance to benefit from dairy as these processes reduce lactose content. The ability to digest lactose has influenced dietary practices, leading to higher demand for dairy products in regions like Wisconsin, where a significant portion of the population is lactose tolerant.