MedWire News: The link between diet and Crohn's disease (CD) has been strengthened by a small but rigorous controlled trial.

A team from Austria reports that patients assigned to a highly restricted diet of organic food showed improvement in their intestinal lesions not seen in patients assigned to a high-carbohydrate diet.

The findings, published in the journal Inflammatory Bowel Diseases, support the theory that matter ingested as part of the modern Western lifestyle causes intestinal Crohn's lesions to persist.

The increase in incidence of CD in the second half of the 20th century, and the earlier age of onset in recent years are just two of the many observations that suggest environmental hazards associated with a Western lifestyle contribute to CD.

As CD is primarily a disease of the gut, it is widely believed that the environmental factors responsible are part of the Western diet. But no factors have yet been convincingly singled out.

Christoph Gasche (Klinik fur Innere Medizin, Vienna, Austria) and colleagues tested the therapeutic effect of a highly restricted diet, based on spelt bread and red meat from intensively monitored organic farming, on five patients with moderate-to-severe CD.

When four of the five patients showed significant improvement, as assessed by magnetic resonance imaging (MRI) and endoscopy, after just 4 weeks, they further tested the diet in a controlled trial of 14 patients.

Five of the patients received the restricted diet, while the other nine received a control diet, low in fiber and fat, and high in carbohydrate.

After 6 weeks, magnetic resonance imaging and endoscopy revealed improvement in the intestinal lesions of three of the four assessable patients assigned to the active diet, compared with just one of the nine controls.

These results were reflected in sonography findings, which showed improvement in four of the five patients given the restricted diet, compared with one of the eight assessable controls.

Gasche and team say the findings "add to our understanding of environmental factors as triggers of CD." But they point out that the small number of patients studied is a "major shortcoming" of the trial and the diet should not be recommended as an intervention at this time.

"The next step in the search for culprit factors may be a stepwise addition of certain nutritional components in patients who responded to this diet," they conclude.

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