High fiber diet without the worry of discomfort

Vegetarian Journal, July-August, 2002 by Reed Mangels

Health professionals are telling you to include more fiber in your diet. Among other advantages, increasing your fiber intake can decrease your risk for some forms of cancer, decrease bad cholesterol levels while maintaining good cholesterol levels, and reduce the risk for heart disease. You may be worried that this recommendation may cause you gastrointestinal discomfort. Good news! According to this new study, the authors conclude you can rest easy and increase your fiber intake without the worries of discomfort.

Few studies have examined the effect of high dietary fiber intake for extended periods of time on gastrointestinal discomfort. In an effort to gain a better understanding of these effects, a recent scientific report examined more than 1,200 women who consumed varying amounts of fiber and maintained this diet for one year. The women were selected from the Women's Healthy Eating and Living (WHEL) Study, which looked at the effects of diet on breast cancer. Women were divided into two groups: the first group increased their fiber intake, and the second group maintained their original fiber intake. Women in the first group were encouraged to increase their fiber consumption to 30 grams per day by consuming vegetables, fruits, legumes, and whole grain products. Women in the second group were encouraged to eat at least 5 servings of fruits and vegetables per day. Over the course of the study, fiber intake was increased only in the first group. Both groups were asked to complete a questionnaire related to gastrointestinal symptoms such as bloating/gas, constipation, diarrhea, heartburn, and upset stomach. After each four-month time interval, the participants rated the level of these symptoms using four categories: "symptoms did not occur," "mild," "moderate," or "severe." "Mild" was defined as symptoms did not interfere with usual activities, "moderate" included symptoms that interfered somewhat with usual activity, and "severe" was classified as so bothersome that usual activities could not be performed. Analysis was carried out based on classification in these groups and fiber consumption.

After the one-year study period and analysis, results indicated that higher dietary fiber consumption is not associated with gastrointestinal discomfort. Participants who consumed a higher fiber diet (more than 35 grams of fiber daily) reported only 40% of the constipation symptoms as compared with the women who consumed a lower fiber diet (35 grams or fewer per day). In addition, participants who consumed a higher fiber diet reported only about 70% of the heartburn symptoms as compared to those on the lower fiber diet. Fiber intake did not appear to be associated with symptoms of diarrhea, bloating, gas, or upset stomach.

Based on this study, in combination with other studies reviewed in the article, the authors concluded that high fiber consumption is not associated with any adverse gastrointestinal effects. Listen to your health professional's pleas and increase your fiber intake without the worries!

McEligot AJ, Gilpin EA, et al. 2002. High dietary fiber consumption is not associated with gastrointestinal discomfort in a diet intervention trial. J Am Diet Assoc 102(4):549-551.

Contributed by Erin M. Crandell, VRG Intern and University of Michigan MPH and RD Candidate