What is the role of the digestive system in human nutrition?

The digestive system is essential for breaking down food into nutrients, which the body absorbs to fuel its activities and support growth. The system begins in the mouth, where food is chewed and mixed with saliva to begin the digestion process. It continues in the stomach, where enzymes break down proteins, and in the small intestine, where most nutrients are absorbed. The liver, pancreas, and gallbladder also play key roles by secreting enzymes and bile that aid in digestion. Waste products that are not absorbed are then passed to the large intestine, where water is removed before excretion.