NEW YORK, Mar 08 (Reuters Health) - A special diet that excludes certain "ultrafine" particles found in some foods may fight the intestinal disorder Crohn's disease, according to results from a small study in the UK.

In a study of 20 Crohn's disease patients, researchers found that the half who were put on a "low-microparticle" diet experienced a significant improvement in their symptoms over 4 months. The diet, which prohibits many processed foods, may help by reducing inflammation in the small intestine, according to a report in the February issue of the European Journal of Gastroenterology and Hepatology.

Crohn's is an inflammatory bowel disease marked by abdominal pain and diarrhea. Inflammation in the small intestine can also lead to complications such as poor absorption of nutrients. While researchers believe genetic factors are involved in the development of Crohn's, the exact cause remains unknown.

Treatment may include drugs such corticosteroids, which ease the bowel inflammation, or surgery to remove the part of the intestine affected by the disease. No single diet has proven effective against Crohn's.

In the current study, Dr. Jonathan J. Powell and his colleagues at St. Thomas' Hospital in London tested the theory that "undegradable" microparticles that get into foods either naturally or through additives might worsen the inflammation seen in Crohn's.

In earlier research, the investigators found such particles--mainly titanium dioxide and aluminosilicates--in intestinal cells. Titanium dioxide is a "whitening" agent used in candy and other confections, some cheeses and sauces, toothpaste and many medications. Aluminosilicates prevent caking and are therefore often used in granular and powdered food products, according to the report.

So Powell's team developed a diet that excluded these types of products: gone were ready-made meals, processed meats, fish and cheese, and instant noodle products. Study patients who followed the diet also peeled and washed fresh fruits and vegetables to cut down on soil residue. And they avoided over-the-counter drugs, which often contain titanium dioxide.

Both study groups avoided high-fiber fruits and vegetables, whole-grain flours and cereals with fruit or nuts. Low-fiber diets have been shown to help some Crohn's patients.

After 4 months, Powell's team found that seven of the nine patients on the diet were in remission, compared with none of those in the other group.

A Crohn's expert not involved in the study called the results "interesting and important."

Dr. Bret Lashner of the Cleveland Clinic Foundation in Ohio told Reuters Health that the microparticle theory is a "novel and unique hypothesis" on how diet can worsen Crohn's symptoms. Moreover, he said, "this is not a fad diet. It has reasonable restrictions."

Still, Lashner said, "I don't think people with Crohn's should run out and try this."

The disease is complex, Lashner explained, and dietary recommendations need to be individualized.

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