Ingested food and beverages are processed in your digestive tract and broken down into nutrients that your body can use for various metabolic functions. Nutrient molecules are absorbed through the lining of the small intestine into your bloodstream and transported throughout your body. Fiber, which is the indigestible part of food, along with older cells from the lining of the digestive tract and some water are eliminated as stool.
Types of Fiber
Fiber is a carbohydrate that cannot be digested. You may have heard the terms soluble and insoluble fiber. Soluble fiber partially dissolves in water, while insoluble fiber, as the name implies, does not. Whole grains, such as oatmeal, legumes such as black beans and kidney beans, vegetables including broccoli, brussels sprouts and lentils are all dietary sources of soluble fiber. Insoluble fiber sources include whole grain bread and whole grain breakfast cereals, bulgur, couscous, brown rice, nuts and vegetables such as celery, green beans and cauliflower.
Role of Fiber
The main role of fiber is to keep the digestive tract functioning smoothly. Since fiber is indigestible, it passes into the intestines and absorbs water. Soluble fiber partially dissolves in water and takes on a gel-like consistency. Insoluble fiber, because it does not break down in water, increases stool bulk and aids in the smooth movement of waste through your digestive tract.
Recommendations for Fiber Intake
Total fiber intake is important to maintain a healthy digestive system. You can achieve this goal by including both soluble and insoluble fiber in your daily diet. The Dietary Guidelines for Americans recommends a daily dietary intake of 14 g of fiber for every 1,000 ingested calories. More simply, older children, adolescents and adults should eat 20 to 35 g of fiber each day. Including whole grains, fruits, vegetables and dried beans in your diet ensures that you are getting enough fiber in your diet. Drink plenty of fluids to help fiber pass through your digestive system.
Health Benefits of Fiber
A high dietary intake of fiber, particularly soluble fiber, is linked to a decreased risk of heart disease. Your body normally eliminates bile through the excretion of bile acids. By binding to bile acids, soluble fiber increases the excretion of cholesterol. Having a low blood cholesterol level is associated with a decreased risk for developing heart disease. Insoluble fiber softens the consistency of stool, thus helping to treat and prevent constipation, the development of hemorrhoids and diverticular disease.
