Acacia fiber is a type of soluble fiber; soluble fiber gels in water and may help control cholesterol and blood glucose levels. Another type of dietary fiber, insoluble fiber, does not dissolve in water. Instead, it helps bulk stool and move it through the intestine, thus helping improve constipation symptoms.Acacia fiber is a type of soluble fiber; soluble fiber gels in water and may help control cholesterol and blood glucose levels. Another type of dietary fiber, insoluble fiber, does not dissolve in water. Instead, it helps bulk stool and move it through the intestine, thus helping improve constipation symptoms.