Measurement of low dietary fiber intake as a risk factor for chronic constipation in children

Scarce information exists regarding dietary fiber intake in children with chronic constipation. The objective of this case-control study was to evaluate the intake of fiber as a risk factor for chronic constipation.

Fifty-two children with a mean age of 6.8+/-3.2 years who had chronic constipation were age and gender matched with 52 children with normal intestinal habits. The fiber content of the diet was evaluated with a 24-hour dietary recall. Two tables of fiber composition in foods were used: a Brazilian table, and a table based on the method of the Association of Official Agricultural Chemists (AOAC).

According to the Brazilian table, the median intake of fiber (in grams per day) by the constipated and the control groups was 13.8 and 17.3, respectively, for total fiber (p = 0.020), 6.8 and 9.7 for insoluble fiber (p = 0.004), and 6.5 and 7.6 for soluble fiber (p = 0.104). According to the AOAC table, the constipation group (9.7 g/day) also had lower (p = 0.0022) intake of total fiber than the control group (12.6 g/day). The coefficient of correlation between the two tables on fiber content of food was +0.82 (p < 0.001) in the constipation group and +0.86 (p < 0.001) in the control group. The intake of fiber was less than the minimum recommendation (age + 5 g) and statistically associated (p = 0.001) with the constipation group (75.0%) in comparison with the controls (42.5%). The odds ratio was 4.1 (95% confidence limits, 1.64-10.32).

Intake of fiber below the minimum recommendation is a risk factor for chronic constipation in children.