Dietary fibers refer to the indigestible parts of plants and plant products that are in the food we eat. They are made up of carbohydrates but the types that our digestive enzymes cannot break down into simple sugars. Hence, they are not absorbed. They simply pass through the digestive tract, intact, and later form part of our feces. Yet, despite the fact that they are not absorbed, dietary fibers provide a number of health benefits.
There are two main types of dietary fibers: soluble and insoluble. Soluble fibers as the name suggests are water soluble. Example of soluble fiber such as oat meal, hold water and turn to gel during digestion. In contrast, insoluble fibers such as those in brown rice or skins of fruits do not hold water. They are metabolically inert and only provide bulk. Most plant-based foods contain both insoluble and soluble fibers and both are essential for us.
Soluble fibers decrease our risk of developing heart disease by lowering blood cholesterol and reducing blood pressure and inflammation. They lower blood cholesterol especially low-density lipoprotein (bad cholesterol or the LDL cholesterol) by binding to cholesterol particles in the digestive tract. A landmark study from Harvard University showed that men who consumed the highest levels of dietary fiber (around 28.9 grams per day) had a 40 percent lower risk of heart disease. In addition, soluble fibers also help prevent and control type 2 diabetes. They lower blood sugar levels by slowing the absorption of sugar in the digestive tract and improve insulin sensitivity.
Insoluble fibers, on the other hand, speed up the elimination of toxic substances from the colon by hastening the movement of materials through the organ. Detoxification also happens since the fiber cleans the surface of the colon naturally. They also increase the bulk of—and soften—stool, leading to regular bowel movements and decreased incidence of constipation and hemorrhoids.
High fiber foods also help in maintaining your body weight. Because they are more filling, people eat less. Research has shown that for every 10-gram increase in soluble fiber, eaten per day, belly fat is reduced by almost four percent in a period of five years. Evidence further indicates that dietary fibers prevent colorectal cancer and other diseases including gastroesopageal reflux disease, duodenal ulcer, and diverticulitis.
The recommended daily intake of dietary fibers is 25 grams in women and 38 grams in men—a little less in people above 50. Foods that are high in dietary fibers include whole-grain products such as brown rice, oat meal, wheat bread, and bran; fruits; vegetables, especially green leafy ones; beans, peas and other legumes; nuts; and seeds.
In general, you get enough dietary fibers if you eat five servings of fruits and vegetables per day together with some servings of whole grain products.
Incidentally, dietary fibers increase intestinal gas formation. Hence, to avoid bloating and abdominal cramps, the shift to a high fiber diet should be gradual—over a period of a few weeks. This will allow the beneficial bacteria in the digestive tract to adjust to the change.
Source – Manila Bulletin – http://www.mb.com.ph/why-fiber-is-essential-for-good-health/#LqGsKCtflE1egrGP.99