The question of why adults in some countries drink milk calmly while in others they avoid it has both cultural and biological explanations. Milk, which has become a symbol of childhood and a source of calcium, turned out to be a product differently perceived by the human body. The ability to digest lactose is a natural phenomenon distributed extremely unevenly around the planet. This is one of the rare manifestations of how evolution, geography, and traditions have shaped the food habits of peoples. The Genetics of the Milk Question The key to understanding the attitude towards milk in adults lies in genetics. Initially, all humans, like most mammals, lost the ability to digest lactose after childhood. The lactase enzyme, which breaks down milk sugar, stopped being produced approximately after three years, when the offspring completed breastfeeding. However, several thousand years ago, a mutation arose in some populations that allowed them to maintain the activity of lactase into adulthood. This process, known as lactase persistence, was closely linked to the development of animal husbandry. Those who could digest milk received an additional source of energy and protein, especially in conditions of food scarcity. Genetic advantage promoted survival and the transmission of the trait to offspring. Thus, regions where milk became part of the traditional diet were formed. Where Milk Did Not Become the Norm The modern map of milk consumption astonishingly accurately reflects ancient migration routes and economic development. The greatest ability to digest lactose is observed among peoples of Northern and Central Europe — in Scandinavia, the Netherlands, Germany, and the United Kingdom. Here, more than 90 percent of adults can drink milk without any consequences. A completely different picture is observed in countries of Eastern Asia, Africa, and South America. In China, Japan, Vietnam, and Korea, the majority of the population is intolerant to lactose: the level of lacta ... Read more