Fiber, commonly known as roughage, is the part of plant-based foods—such as fruits, vegetables, grains, beans, or nuts—that the body can’t digest. Dietary fiber is often divided into two broad types: soluble and insoluble.
If you mix soluble fiber in water, it dissolves and forms a gel. Soluble fiber is found in psyllium, oats, apples and other fruits, beans, peas, and chia seeds. Insoluble fiber won’t dissolve in water, but it absorbs water, puffing up like forgotten cereal in a bowl of milk. Insoluble fiber is found in vegetables, nuts, flaxseeds, and whole grains.
In addition to being soluble or insoluble, fibers differ in other ways: size, ability to hold water, viscosity (thickness), and resistance to being broken down. All of these characteristics determine the effects a particular fiber has on the body, and these effects are much more widespread than simply providing a little dietary bulk.
Health Benefits of Fiber:
Normalizes bowel movements
Fiber’s role in normalizing bowel movements is probably its most well-known role, and fiber can be beneficial in cases of either constipation or diarrhea. Fiber adds bulk to stool, making difficult stools larger, softer, and easier to pass. On the other hand, fiber absorbs water and helps to add consistency to more liquid stools.
Supports healthy weight
Because fiber is indigestible, it adds no calories, but it takes up space in the intestines and slows emptying of the stomach. The added bulk reduces the amount of food needed to feel satisfied, and the increased time in the stomach helps you feel fuller longer. In fact, increased dietary fiber is associated with a lower incidence of obesity.
The gel formed from certain soluble fibers, particularly oats, barley, and psyllium, can bind to cholesterol in the intestines. This increases the elimination of cholesterol in the stool and lowers cholesterol in the body, especially LDL, the “bad cholesterol.” In addition, high fiber diets are associated with a decreased cardiovascular disease risk and incidence of events such as heart attacks.
Stabilizes blood sugar
Increasing fiber intake appears to help normalize and mitigate the rise in blood sugar and insulin after eating. Although the mechanism isn’t fully understood, the effects may be due to slower absorption of glucose in the intestines or by increasing the expression of certain genes and hormones that impact blood sugar levels.
How much fiber is enough?
The recommended adequate intake (AI) for total fiber is 38 grams per day for men age 19-50 and 25 grams per day for women age 19-50. For men and women over 50, the recommended AI is 30 and 21 grams per day, respectively.1 However, the average daily intake for most people in the United States falls far short of this target, hovering around 15 grams per day since 1999.2 As you increase your fiber intake, it is important to do so gradually and drink plenty of water to avoid the bloating and intestinal discomfort that can occur when you increase your intake too dramatically too quickly. To achieve maximum health benefits, eat an assortment of plant based foods to obtain a variety of soluble and insoluble fibers. If you are having difficulty getting the suggested amount using diet alone, consider increasing your intake with a fiber supplement. A little bit of fiber can go a long way in improving your overall health.
About the Author:
Dr. Lise Naugle is an associate of Dr. James L. Wilson. She assists healthcare professionals with clinical assessment and treatment protocols related to adrenal dysfunction and stress, and questions regarding the use of Doctor Wilson’s Original Formulations supplements. With eleven years in private practice and a focus on stress, adrenals, hormonal balance and mind-body connection, she offers both clinical astuteness and a wealth of practical knowledge. Dr. Naugle also maintains updated information about the latest scientific research on the hypothalamic-pituitary-adrenal axis function, endocrine balance and nutritional support for stress and develops educational materials about stress and health for clinicians and their patients.
- Institute of Medicine. Dietary, Functional, and Total Fiber. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, D. C.: National Academies Press; 2002:265-334.
- King DE, Mainous AG 3rd, Lambourne CA. Trends in dietary fiber intake in the United States, 1999-2008. J Acad Nutr Diet. 2012 May; 112(5):642-8.
- Kumar V, Sinha AK, Makkar HP, de Boeck G, Becker K. Dietary roles of non-starch polysachharides in human nutrition: a review. Crit Rev Food Sci Nutr. 2012;52(10):899-935.