Griffenberg, L., Morris, M., Atkinson, N., & Levenback, C. (1997). The effect of dietary fiber on bowel function following radical hysterectomy: A randomized trial. Gynecologic Oncology, 66, 417–424.

To evaluate the effect of fiber on bowel function by comparing increased fiber intake with instructions versus regular diet.

Women were randomized into two groups: high fiber (treatment) or regular diet (control). Both groups were evaluated at one, four, and seven months after surgery.

The treatment group received dietary counseling with instructions to increase their dietary intake to 30 to 40 g per day. Patients received all-bran cereal (unmarked) containing 15 g of fiber per bowl. Patients also were encouraged to increase their intake of insoluble fibers (eg, whole-grain, whole-wheat, and pumpernickel breads; all-bran cereal; butter; lima, pinto, and white beans; split and black-eyed peas; blackberries; boysenberries; raspberries; dried figs and prunes; artichokes; asparagus; Brussels sprouts; corn; parsnips; spinach; winter squash; turnip greens).

The study reported on a sample of 35 women with cervical cancer who had a type II or III radical hysterectomy.

University of Texas MD Anderson Cencer Center

This was a randomized controlled trial (RCT).

• Use of medications to achieve regularity was measured in terms of straining and pain with elimination.
• Patients completed subjective questionnaires, exercise log (seven days), food diary (three days), and bowel function assessment (seven days) at intervals. 

• Mean daily dietary fiber intake was 22.4 g in the treatment group and 12.4 g in the control group.
• Insoluble fiber intake for the treatment and control groups was 16.2 g and 8.1 g, respectively.
• Caloric intake was discussed.
• Patients in the control group had a significant increase in the amount of medications used to achieve regularity; no other significant changes existed pre-/postoperation in either group.

Patients with higher fiber intake had significantly less cramping abdominal pain and reports of straining, bowel-movement retention, more bowel movements with gas, and made in less than three minutes.

• The sample size was small (fewer than 100). Although this was an RCT, the sample size of 35 could be considered a major flaw and, therefore, decreased the impact level of evidence.
• The sample comprised women only.
• Findings were postsurgical only; presurgical fiber intake for the control group (10 g) was significantly higher than in the treatment group (7 g, p = 0.005).