Nutritionists recommend between 25 to 40 grams of dietary fiber; two thirds should be the hard fiber called insoluble. This is the kind that many know as roughage. It's job is mostly to sweep up all the waste and make sure it can form into a proper stool, not too hard, not too soft.
The other type is soluble fiber, or soft fiber which absorbs water. This is the prebiotic fiber and one third of all fiber should be this type. Why is this fiber the prebiotic? All dietary fiber is indigestible, which means it passes through the entire digestive system intact. When the soluble fiber arrives in the large intestine (colon), it absorbs water and starts a fermentation process. It's because of this fermentation it is able to feed our good bacteria (probiotics) in the colon.
This process also can stop the growth of bad bacteria. This is very important because without enough of this soluble fiber, bad bacteria may form into cells along the intestinal wall and over a long period of time can turn into cancerous polyps. This means prebiotic fiber may play a big role in helping to prevent colon cancer.
It's these findings that scientists are studying and creating such a big interest in prebiotics because they are playing the key role in having the right balance of good and bad bacteria in our intestinal tract. Scientists know that what happens in our intestines has a major consequence in our health so these findings have been very exciting and important.
Prebiotics have also been linked to helping with weight gain, speeding up waste transit time, helping to lower cholesterol, balancing blood sugar levels, and ease symptoms of inflammatory bowel disease.
How can we get prebiotic fiber?
Prebiotic foods include many of the grains, but only unrefined or raw grains such as brown rice, raw oats and barley, whole grain bread. Many raw vegetables and a wide variety of fresh fruits. These are foods many of us simply don't choose to eat. Instead we focus on eating fast food or processed food which has most of the dietary fiber cooked right out of them.