Galactose is a simple sugar, or monosaccharide, that is found in milk and dairy products. It is one of the building blocks of lactose, the sugar present in milk. When we consume lactose, our bodies break it down into glucose and galactose, which can then be used for energy. In addition to its role in dairy, galactose is important for various biological processes. It is involved in the formation of glycoproteins and glycolipids, which are essential for cell communication and structure. People with a condition called galactosemia cannot properly metabolize galactose, leading to health issues if they consume dairy.