Urine test reveals gluten-free diet compliance

Last Updated: 2015-12-08

By David Douglas

NEW YORK (Reuters Health) - Gluten immunogenic peptides (GIP) in the urine of patients with celiac disease are indicative of even occasional dietary transgressions, according to Spanish and U.S. researchers.

In a report online November 25 in Gut, Dr. Carolina Sousa of the University of Seville and colleagues note that ensuring compliance with a gluten-free diet (GFD) is essential for such patients to avoid gut mucosal damage.

However, doing so is difficult and perhaps more than half of patients who declare full adherence to a GFD may not do so, "probably because of inadvertent lapses in daily gluten intake."

"To date," the researchers add, "available methods to monitor GFD compliance only measure the consequences of dietary transgressions and many studies have reported poor effectiveness." Also, endoscopy, to collect biopsies and assess mucosal healing, "is invasive, expensive and not a practical method for serial monitoring."

To investigate the utility of a GIP assay, the researchers examined urine samples from 76 healthy individuals and 58 patients with celiac disease subjected to different gluten dietary conditions.

Single gluten intake in healthy individuals who had previously followed a GFD was detectable by GIP assay in as little as four hours and remained so for up to two days. In addition, the assay "revealed infringement of the GFD in about 50% of the patients."

Analysis of duodenal biopsies revealed that most of the patients without villous atrophy (89%) had no detectable GIP in their urine. However, all patients with quantifiable GIP in their urine showed incomplete intestinal mucosa recovery.

The researchers call for larger studies but conclude that the method is "sensitive, specific and simple enough to be convenient for clinical monitoring of patients with CD as well as for basic and clinical research applications including drug development."

Dr. Sousa told Reuters Health by email that this "is a significant advance that opens up new possibilities for the gastroenterologist to control the treatment of this disease, assess GFD compliance and improve the quality of life of patients with CD."

Dr. Amado S. Peña, who was not involved in the study, told Reuters Health by email that the study is "An excellent example of translational medicine."

Dr. Peña, professor emeritus of gastrointestinal immunology at VU Medical Center in Amsterdam, added that "It seems to be a reliable, objective test of great usefulness for the patients and their physicians to cope with the difficulties of following a gluten-free diet."

The study had no commercial funding. Dr. Sousa and three of her coauthors have applied for a patent on the new method. Three of the authors are employed by Biomedal SL, a Spanish biotech company whose products were used in the study.

SOURCE: http://bit.ly/1RBQHl8

Gut 2015.