Diet and chronic constipation in children: the role of fiber

Chronic constipation is one of the most common disorders in Western countries and despite numerous clinical, pathophysiologic, and epidemiologic studies its cause is still unclear. Several hypotheses have been proposed and according to experimental studies and clinical observation, fiber intake could play a role in its pathogenesis. The purpose of this case-control study was to examine the possible correlation of idiopathic chronic constipation in children and dietary intake, particularly fiber intake.

A randomized sample of children (291 children with constipation and 1602 controls) aged 2 to 14 years was taken from three of the 52 counties of Greece. Stratification was performed on the basis of urban, rural, or suburban location and socioeconomic status. The nutritional data were obtained from a 3-day dietary record and a dietary history. Statistical analysis was performed with multivariate tests, multivariate analysis of variance, discriminant analysis, and chi-square analysis according to the characteristics of the correlated variables.

Constipated children had a lower caloric and nutrient intake (p < 0.001), lower body weight/height (p < 0.001), and higher prevalence of reported anorexia (p < 0.001). Discriminant analysis indicated that dietary fiber alone was independently negatively correlated with chronic constipation, despite the age and the age of onset of constipation. Relative risk also had a negative correlation with fiber intake (p < 0.001). Of the main fiber fractions only cellulose and pentose were independently correlated with chronic constipation.

Lack of fiber may play an important role in the etiology of chronic idiopathic constipation in children.