Monday, February 12, 2018

Treating and preventing disease with dietary fiber

- Jennifer Middleton, MD, MPH

The current issue of AFP includes a review article on Hemorrhoids: Diagnosis and Treatment Options that discusses the roles fiber intake has both in contributing to hemorrhoids (when too low) and treating them (when appropriately increased). The authors recommend that patients with hemorrhoids increase their fiber intake to 25-35 grams per day and provide a link to a handout listing high fiber foods. As a high fiber diet can also help prevent and treat hyperlipidemia, constipation, and diverticulosis, family physicians should be proficient in discussing this important digestive component with patients.

Adequate daily fiber intake may protect against the development of hyperlipidemia. Children with chronic constipation consume less fiber than their peers with normal bowel patterns. Inadequate fiber intake is associated with the development of diverticulosis, which can put patients at risk for diverticulitis.

Increasing dietary fiber can modestly reduce LDL levels, improve constipation, and, along with exercise and weight loss if indicated, reduce the risk of recurrent diverticulitis. (Of note, a Cochrane meta-analysis found no role for using fiber supplementation to improve symptoms of irritable bowel syndrome.) Increasing fiber by increasing consumption of high-fiber whole foods, and not with fiber product supplementation, provides the most benefit.

Most Americans consume less than half of those recommended 25-35 grams of fiber daily, though many are trying to increase their consumption by choosing more fruits, vegetables, and whole grain products. Unfortunately, many products marketed as "whole grain" in the United States contain very little fiber. We should counsel patients to look beyond claims about whole grain content and examine food labels to choose products with a minimum of 3 grams of fiber per serving. Advising patients, also, to gradually increase their fiber intake may help them minimize the unpleasantness of bloating and excess flatulence that can accompany a rapid change in fiber consumption. Patients may find nutrition tracking apps such as My Diet Coach, reviewed in the current issue of Family Practice Management, to be useful in monitoring their daily fiber intake. Other apps such as (Fooducate and Shopwellcan help patients make more informed choices at the grocery store.

Providing specific advice in the context of motivational interviewing increases our patients' likelihood of success at making any behavioral modification stick; there's an AFP By Topic on Health Maintenance and Counseling as well as an AFP By Topic on Nutrition if you'd like to read more. What resources have you found useful to help patients increase their daily fiber intake?