Fiber: Just the Facts

Fiber in breakfast cereal

Constipation is a common gastro-intestinal complaint in older adults and is more common in women than men.1 There are some age-related changes in the gut that predispose older individuals to constipation, including decreased elasticity of the colon muscles, but diets low in fiber and water are bigger culprits than physiological changes.1

Most Americans are woefully short on getting adequate fiber in their diets. The average intake is 17 grams of fiber a day and only five percent of Americans reach the Adequate Intake for fiber (25 grams/day for women and 38 grams/day for men.)2 Are you getting enough fibers in your diet? The “s” on the end of fiber is there for a reason. Dr. Julie Miller Jones, a professor and researcher from St. Paul, Minnesota, says, “We should talk about fibers, like we talk about vitamins, because they do different things for our health.” Dr. Jones says that many people believe that “fruit and vegetables provide all the fiber anyone needs, but it is hard to reach fiber goals without including grains.”

Daily Fiber Goals for Men and Women

Fiber is defined as the dietary material or roughage in foods that can’t be broken down in the stomach or intestines, so it passes through the body. 2,3 Fiber can aid in regular bowel movements and fiber comes in basically two types, called insoluble and soluble fiber. Insoluble fiber is the kind found in cereals and other grains and acts like a broom to sweep clean the gastro-intestinal tract and promote regularity. Soluble fiber is found in fruits and vegetables and helps regulate blood sugar and cholesterol. We need both types of fibers and most foods have a bit of both types, but to tackle the fiber shortage and improve regularity, choose grains.

Grains, especially the fiber found in wheat, are very effective for regularity due to the high bulking effect and resistance to fermentation in the large intestine. Oat fiber and corn fiber are also effective fibers for relieving constipation.

One easy, and delicious, way to increase insoluble fiber is to include a high fiber breakfast cereal. Just a half-cup serving contains 9 to 14 grams of fiber, depending on the brand. A high fiber cereal can be used in many ways to boost fiber intake: crush the cereal for a crunchy topping on vegetables, casseroles, or macaroni and cheese, or mix it into granola or trail mix, mix with uncooked oats and sprinkle of brown sugar for a sweet topping on fruit, ice cream, or cobblers.

Label claims can lead you think a food is higher in fiber than it is. If a food product claims to be a “good source” of fiber, that means it has 2.5 grams of fiber per serving. An “excellent” source means a serving has at least 5 grams. For a link to more high fiber foods, see https://health.gov/dietaryguidelines/2015/guidelines/appendix-13/. There is also more information on grains and fiber at https://healthyaging.grainfoodsfoundation.org/infographic/breaking-fiber-much-fiber-favorite-foods/.

References

1McClave SA. Common gastrointestinal complains in older adults. In Bales CW & Ritchie CS (Eds), Handbook of Clinical Nutrition & Aging. 2nd ed. Humana Press, New York, NY; 2009:pp121-136.

2Dahl WJ & Stewart ML. Position of the Academy of Nutrition and Dietetics: health implications of dietary fiber. J Acad Nutr Diet. 2015;115:1861-1870.

3McRorie JW & McKeown NM. Understanding the physics of functional fibers in the gastrointestinal tract: an evidence-based approach to resolving enduring misconceptions about insoluble and soluble fiber. J Acad Nutr Diet. 2017;117:251-264.