The short-term effects of olive oil and flaxseed oil for the treatment of constipation in hemodialysis patients.
OBJECTIVES
To evaluate the effects of olive oil and flaxseed oil compared with mineral oil for the treatment of constipation in patients undergoing hemodialysis.


METHODS
A 4-week, double-blind, randomized, and controlled trial was conducted. Fifty constipated patients (29% male, 51 ± 12 years) diagnosed by the Rome III criteria were randomly assigned to receive mineral oil (control group; n = 17), olive oil (n = 16), or flaxseed oil (n = 17). The initial oil dose was 4 mL/day, and adjustments during the follow-up could be made as needed. The impact of the intervention was assessed by the Rome III criteria scores.


RESULTS
The most frequent symptoms of constipation evaluated by the Roma III criteria at baseline were comparable among the groups and included "incomplete evacuation" (92%), "lumpy or hard stools," (72%) and "anorectal obstruction" (70%). The Rome III score improved significantly in patients receiving mineral oil (10.5 ± 5.0 to 4.1 ± 4.0; P < .01), olive oil (10.3 ± 4.2 to 3.2 ± 3.8; P = .01), and flaxseed oil (9.6 ± 4.2 to 6.0 ± 5.1; P < .01), with no significant group-by-time interaction (P = .15). The scores of 5 from 6 constipation symptoms reduced similarly in the mineral oil and olive oil groups, whereas only the frequency of evacuation and the consistency of stools improved in the flaxseed oil group.


CONCLUSIONS
We demonstrated that the daily use of olive oil or flaxseed oil was as effective as mineral oil in the treatment of constipation in patients undergoing hemodialysis.