More Fiber, Less Tummy Trouble

High fiber diet linked to lower Crohns disease risk

(RxWiki News) With inflammatory bowel disease, the immune system attacks the body’s cells instead of foreign cells, causing severe tummy trouble. It has been suggested that a high-fiber diet may help keep these diseases at bay.

A recent study found that consuming fiber long-term was associated with a lower risk of developing Crohn’s disease, a type of inflammatory bowel disease.

According to the study, fiber that comes from fruit was especially effective in lowering the risk for Crohn’s disease. But the study did not find any association between fiber consumption and ulcerative colitis, another kind of inflammatory bowel disease.

"Hungry? Grab some fruit!"

This study was conducted by Ashwin N. Ananthakrishnan, MD, MPH, from the Division of Gastroenterology at Massachusetts General Hospital and Harvard Medical School in Boston, along with colleagues.

The aim of this study was to examine the association between long-term intake of dietary fiber and the risk for inflammatory bowel disease.

Inflammatory bowel disease is a condition in which the immune system attacks the body’s own cells and causes swelling and sores in the lining of the gut. This can cause diarrhea, blood in the stools and abdominal pain.

The two main types of inflammatory bowel disease are ulcerative colitis and Crohn’s disease.

Increased intake of dietary fiber has been proposed to reduce risk of inflammatory bowel diseases, but previous studies looking at this link have been small in size or have only considered data at a single point in time.

During the current study, the researchers looked at data from 170,776 women over a 26-year period. Information about types of foods eaten was collected via questionnaires administered every four years.

The diagnosis of inflammatory bowel disease was obtained via questionnaires and confirmed by review of the patients’ medical records.

Participants were divided into categories based on their total fiber intake. In the category with the lowest consumption, the fiber intake averaged 11 grams per day, while participants in the highest consumption category consumed 25 grams of fiber per day.

Upon analyzing the data, the researchers found that there were a total of 269 cases of Crohn’s disease and 338 cases of ulcerative colitis among the study population.

Patients whose average intake of fiber was the highest had a 40 percent lower risk of developing Crohn’s disease as compared to those who had the lowest average dietary fiber consumption.

This protective effect of fiber was greatest when the fiber came from fruits, but fiber that came from cereals, whole grains or beans did not change the risk of developing the disease.

The researchers found that neither total intake of dietary fiber nor fiber from any specific source such as fruits appeared to make a significant difference in the risk of developing ulcerative colitis.

Based on their results, the researchers concluded that long-term intake of dietary fiber, especially fiber contained in fruit, was associated with a lower risk for Crohn’s disease.

According to Maxwell Chait, MD, FACP, gastroenterologist at Columbia Doctors Medical group, “The forms of inflammatory bowel disease, Crohn's disease and ulcerative colitis, are believed to result from a combination of genetic and environmental factors, and some evidence suggests that dietary fiber may play a role, possibly through effects on the gut microflora, epithelial barrier function, the prevention of bacterial movement and other biochemical mechanisms.

“The risk of Crohn's disease in patients who consumed the highest amount of fiber was primarily lowered with consumption of soluble fiber. In contrast, consumption of insoluble fiber did not decrease risk,” said Dr. Chait.

Soluble fiber is the type of fiber present in fruits and vegetables, whereas insoluble fiber is found in whole grains, cereals and beans.

“Further research is warranted to explore the biological mechanisms by which fiber influences the risk for Crohn's disease and the differences in results in ulcerative colitis,” Dr. Chait recommended.

The results of this study were published in August in Gastroenterology.

The study was funded by grants from American Gastroenterological Association, Crohn’s and Colitis Foundation of America, the Broad Medical Research Program of the Broad Foundation, and the National Institutes of Health.

Review Date: 
August 20, 2013