Patient Presentation
A 30-month-old male came to clinic for his health supervision visit. The mother was concerned because of infrequent bowel movements and picky eating. “All he’ll eat is pasta and chicken nuggets. No fruit and no vegetables practically. He’ll drink milk and no water,” she explained. “He has hard stools and hides when he is having them in his diaper. They are large too and he seems to have some pain before he poops,” she said. The past medical history showed a healthy male, who was “strong-willed,” per his mother.

The pertinent physical exam revealed normal vital signs and growth was between 75-90%. His examination was normal.

The diagnosis of a healthy child with constipation and poor dietary habits was made. The pediatrician recommended several things to help including starting Miralax® to help with softening the stool. He also recommended some ways to increase dietary fiber including using whole grain foods, increasing the few vegetables he would eat such as corn, and trying some others that the mother could put on his plate or put into other foods such as pasta sauce or blend into a milk-based smoothie.

Discussion
Fiber is an important dietary component. It has many health benefits including decreasing overall mortality and cardiovascular events, improving metabolic profiles such as lipids and glucose and decreasing malignancies especially those of the gastrointestinal tract. Fiber improves constipation, functional abdominal pain, irritable bowel syndrome, and inflammatory bowel disease.

There are several different definitions of dietary fiber, however it is basically recognized as “… a heterogeneous group of non-carbohydrate plant cell wall components (lignin, chitins, and waxes) and carbohydrate polymers that are neither digested nor absorbed by the human intestine (non-starch polysaccharides, resistant oligosaccharides, and resistant starch).”

Dietary fiber comes in many forms but can be divided into insoluble fibers which act as bulking agents within the gastrointestinal tract entrapping water and improving gut transit, or soluble fibers which act as substrate for fermentation within the gut and produce a variety of components which then can be used as their own substrates for gut health. Soluble fibers dissolve in fluid, and slow down gastric emptying and the digestion of starch and other macro nutrients.

Insoluble fibers include “…cellulose, hemicellulose, lignin, chitin and wheat bran.” They are present mainly in fruits, vegetables and whole grain.

Soluble fibers include psyllium, Beta-glucans, guar gum, glucomannan, and pectic polysaccharides. They are found in barley, nuts, oats, pulses (beans, lentils, peas) and some fruits and vegetables.

Although increased fiber can improve many gastrointestinal problems, excessive fiber intake could lead to early satiety and therefore decreased nutrient intake, or increased fermentation leading to potential adverse problems ing “…diarrhea, abdominal distension, flatulence, and vomiting.” Fortunately, usually these problem are not serious.

Learning Point
Fiber in a Western diet is relatively limited overall and about 50% or more children and adults do not get the recommended amount of fiber in their daily diet. In the United States the usual intake is 15 g/ day of fiber.

Adults are generally recommended to have 25-35 g/day of fiber. There is not consensus on the total amount of dietary fiber a child should have. The amount varies depending on age and gender. For example in one to three-year olds leading references vary from 4.5 to 19 grams per day and in 14 to 18 year olds from 19 to 38g per day. The American Health Foundation does use a simple form which = (Age in years) + 5-10g per day. The American Academy of Pediatrics uses 0.5 g fiber/ kilogram/ day as its standard.

As one author noted, “[C]hildren should ingest a variety of fibers from fruits, vegetables, legumes, seeds, nuts, and cereal grains to ensure and achieve the benefits and synergies of different dietary fibers.”

Questions for Further Discussion
1. What are causes of constipation? A review can be found here
2. How do you counsel families to increase their fiber consumption?
3. What are indications for referral to a gastroenterologist?
4. What do picky eaters really eat? A review can be found here

Related Cases

Disease: Dietary Fiber | Constipation

Symptom/Presentation:
Constipation and Encopresis

Specialty: Gastroenterology | Nutrition / Dietetics

Age: Preschooler

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Dietary Fiber and Constipation.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Korczak R, Kamil A, Fleige L, Donovan SM, Slavin JL. Dietary fiber and digestive health in children. Nutrition Reviews. 2017;75(4):241-259. doi:10.1093/nutrit/nuw068

Stephen AM, Champ MMJ, Cloran SJ, et al. Dietary fibre in Europe: current state of knowledge on definitions, sources, recommendations, intakes and relationships to health. Nutr Res Rev. 2017;30(2):149-190. doi:10.1017/S095442241700004X

Snauwaert E, Paglialonga F, Vande Walle J, et al. The benefits of dietary fiber: the gastrointestinal tract and beyond. Pediatr Nephrol. 2023;38(9):2929-2938. doi:10.1007/s00467-022-05837-2

Salvatore S, Battigaglia MS, Murone E, Dozio E, Pensabene L, Agosti M. Dietary Fibers in Healthy Children and in Pediatric Gastrointestinal Disorders: A Practical Guide. Nutrients. 2023;15(9):2208. doi:10.3390/nu15092208

Author
Donna M. D’Alessandro, MD
Professor of Pedia