Plant foods are excellent sources of dietary fiber, a nutrient that is especially important in digestion.  Fiber comes in two forms - soluble and insoluble.  The insoluble type provides bulk to reduce the transit time through the digestive tract; helps relieve constipation, improves colon health, and may have protective effects against colon cancer.  The soluble type holds water in the intestinal tract leading to softer stools and some, such as beta-glucan from oat bran also binds cholesterol and detoxified chemicals from the liver so that they are not reabsorbed.  Experts recommend eating a well-balanced high fiber diet.  Unfortunately, Americans typically consume 10 to 15 grams of fiber a day, even though experts recommend 20 to 35 grams daily. Some fiber-like natural substances known as prebiotics (e.g., inulin and fructo-oligosaccharides), often referred to as soluble fiber, serve as fuel for naturally occurring beneficial bacteria.  Prebiotics and probiotics are sometimes combined in a supplement for adequate reinforcement of beneficial bacterial.  Click here to learn more about fiber and digestive health.