A high-fiber diet does not protect against asymptomatic diverticulosis

Gastroenterology. 2012 Feb;142(2):266-72.e1. doi: 10.1053/j.gastro.2011.10.035. Epub 2011 Nov 4.

Abstract

Background & aims: The complications of diverticulosis cause considerable morbidity in the United States; health care expenditures for this disorder are estimated to be $2.5 billion per year. Many physicians and patients believe that a high-fiber diet and frequent bowel movements prevent the development of diverticulosis. Evidence for these associations is poor. We sought to determine whether low-fiber or high-fat diets, diets that include large quantities of red meat, constipation, or physical inactivity increase risk for asymptomatic diverticulosis.

Methods: We performed a cross-sectional study of 2104 participants, 30-80 years old, who underwent outpatient colonoscopy from 1998 to 2010. Diet and physical activity were assessed in interviews using validated instruments.

Results: The prevalence of diverticulosis increased with age, as expected. High intake of fiber did not reduce the prevalence of diverticulosis. Instead, the quartile with the highest fiber intake had a greater prevalence of diverticulosis than the lowest (prevalence ratio = 1.30; 95% confidence interval, 1.13-1.50). Risk increased when calculated based on intake of total fiber, fiber from grains, soluble fiber, and insoluble fiber. Constipation was not a risk factor. Compared to individuals with <7 bowel movements per week, individuals with >15 bowel movements per week had a 70% greater risk for diverticulosis (prevalence ratio = 1.70; 95% confidence interval, 1.24-2.34). Neither physical inactivity nor intake of fat or red meat was associated with diverticulosis.

Conclusions: A high-fiber diet and increased frequency of bowel movements are associated with greater, rather than lower, prevalence of diverticulosis. Hypotheses regarding risk factors for asymptomatic diverticulosis should be reconsidered.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Asymptomatic Diseases*
  • Constipation / complications
  • Cross-Sectional Studies
  • Diet Surveys
  • Diet*
  • Diet, High-Fat
  • Dietary Fiber*
  • Diverticulosis, Colonic / epidemiology
  • Diverticulosis, Colonic / etiology*
  • Diverticulosis, Colonic / prevention & control
  • Female
  • Humans
  • Logistic Models
  • Male
  • Middle Aged
  • Motor Activity
  • Poisson Distribution
  • Prevalence
  • Risk Factors
  • Sedentary Behavior
  • Surveys and Questionnaires