Oligosaccharides are carbohydrate polymers made up of 2-9 monosaccharide units bonded together with glycosidic bonds. The most important oligosaccharides are disaccharides, which contain two monosaccharides. The three main physiological important disaccharides are sucrose from cane sugar and fruits, lactose from milk, and maltose from cereals and the breakdown of starch. Oligosaccharides are important as they provide energy, regulate blood sugar levels, maintain bowel functions, lower cholesterol, and protect the body from fatigue.