OBJECTIVE: The objective of this study was to evaluate the adherence to and efficacy of dietary fiber in the treatment of functional constipation. METHODS: This is a longitudinal clinical study involving 59 subjects, 54 women and 5 men, aged 18 to 74 years, mean age of 46 years, with functional constipation. Once the bowel movements became regular with the use of dietary fiber, subjects were instructed to maintain the fiber-rich diet for four months in order to determine if the efficacy continued over time and the degree of adherence to its use. The association between adherence and efficacy was investigated by the Fisher's exact test. RESULTS: Although nine individuals abandoned the study, 50 returned. From these, 32 sustained normal bowel movements and 18 had recurrence of the constipation. In the first group, 16 continued consuming the same amount of fiber, four increased, nine reduced and three stopped taking it. In the group with recurrence, three maintained the same amount of fiber, one increased, three reduced and eleven stopped taking it. There was a significant statistical association between adherence and efficacy (p=0.008). CONCLUSION: The long-term efficacy of dietary fiber for the treatment of constipation was moderate (64%) and treatment drop-out rate was high (52%). These results suggest the need of new strategies that promote greater fidelity to fiber therapy, thereby improving the efficacy of constipation treatment.
Dietary fiber; Constipation; Dietary fiber efficacy; Food habits