In 75 percent of the world’s population, the gene for digesting lactose slowly begins to switch off as they get older. This is not surprising, as by then we are no longer reliant on our mothers’ milk, or formula milk, to nourish us. Outside of Western Europe, Australia, and the United States, adults who are tolerant to dairy products are a rarity. Even in our parts of the world, supermarket shelves are increasingly full of lactose-free products.
