Fiber-rich food is one of the fundamental bases to gastrointestinal health. Fiber helps the digestive system absorb nutrients efficiently, and also bulks up the stool, ensuring smooth passage through the colon. Fiber can reduce symptoms of constipation, diarrhea, cramping, bloating and more serious issues, like ulcers. Duodenitis can often lead to ulcers, or even digestive complications due to inflammation. Fiber helps soothe inflammation in the gut and improves overall digestive health.