When you eat plant foods, including grains, vegetables and fruits, you consume a variety of nutrients. The sugar, vitamins, water and minerals from these foods are absorbed through the walls of your intestine into your bloodstream, and then carried to body cells to serve a variety of functions. The complex carbohydrates that make up plant fiber can't pass through your intestinal wall, so they remain inside your gastrointestinal tract to promote normal bowel function, maintain heart health and help you manage your weight. A fiber-rich diet reduces your risk of developing constipation.
Functions
Plant fiber can be categorized as soluble or insoluble. Soluble fiber combines with bile acids in your intestines, ultimately reducing the level of cholesterol in your blood. Insoluble fiber combines with other waste products to produce larger, softer stools that pass easily through your intestines and out of your body. Soluble fiber keeps material moving through your intestines and promotes regular bowel movements.
Recommended Fiber Intake
According to the Institute of Medicine, a 56-year-old man needs 38 g of dietary fiber daily for optimal health. The University of Maryland Medical System publishes an online daily recommended intake calculator that lets you customize fiber recommendations based on your age, height, frame size and physical activity level. A 56-year-old man who is 5 feet 4 inches tall, has a small frame, and lives a sedentary lifestyle needs to eat 21 g of dietary fiber per day, according to the USDA. His 56-year-old neighbor who is 6 feet 2 inches tall, has a large frame and lives a very active lifestyle should obtain at least 38 g of fiber from his daily meals and snacks to avoid constipation.
Meal Guidelines
The American Cancer Institute recommends an easy guideline to ensure your diet has the right mix of soluble and insoluble fiber to prevent constipation. You should fill 2/3 of your plate with a variety of fruits, vegetables, whole grains and beans. The remaining 1/3 of your meal should include lean meat, poultry, fish and/or low-fat dairy products. Drink plenty of water and other fluids so your body has enough liquid to combine with fiber into soft stools.
Sources
Whole grain breads, cereals, pastas and baked goods are packed with insoluble fiber that helps prevent constipation. Whole grain cereals, such as couscous, quinoa, brown rice and bulgur, offer plenty of insoluble fiber. Other good sources of insoluble fiber include dark green leafy vegetables, bran, nuts and cruciferous vegetables, including cabbage, Brussels sprouts and broccoli.
References
- Continuum Health Partners; "Bowel Function and Dietary Fiber"; Warren Enker
- Colorado State University Extension; "Dietary Fiber"; J. Anderson et al; 2010
- Institute of Medicine; "Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids"; September 5, 2002
- University of Maryland Medical System: Fiber Calculator
- American Institute for Cancer Research: The Facts About Fiber; 2006
- MayoClinic.com; Dietary Fiber: Essential for a Healthy Diet; November 19, 2009
