The University of Milan has published a new study in journal Food Research International specifying that digesting bread and pasta can release active molecules that pass through the gut lining. The wheat proteins and molecules produced during digestion cause gluten intolerance and sensitivity in individuals who suffer from celiac disease. Approximately 1% of the general population is impacted by celiac disease or wheat allergy.
The researchers have for the first demonstrated that the molecules produced during digestion include exorphins, which are involved in symptoms of neurological diseases and have been found in the spinal fluid of people with schizophrenia and autism. The new research reveals that two of these molecules – called exorphins A5 and C5 – are released during digestion of real bread and pasta, and that they can survive digestion and pass through an in vitro model of the intestinal lining.
“Previous lab tests have been done on pure gluten, but for the first time we have simulated digestion using real bread and pasta bought from the supermarket to see if these molecules are produced,” said Dr. Milda Stuknyt, one of the authors of the study. “We show that not only are these molecules produced during digestion, but they can also pass through the gut lining, suggesting that they could indeed have a biological effect.”
“We chose to study bread and pasta because they represent such a significant part of our diet, especially in Italy,” said Dr. Stuknyt. “While we know quite a lot about the mechanisms of celiac disease and how it’s connected to gluten, we still know relatively little about non-celiac gluten sensitivity. It’s just as important, and our research provides further insight into the proteins and the derived peptides that could be involved.”
The researchers used two different types of bread and four types of dried spaghetti to digest each sample in a simulated digestion system. The findingds revealed that the levels of exorphins AS and CS were different with twice as much C5 being produced compared to A5; up to 1 milligram of C5 was produced from the in vitro digestion of a single serving size of pasta.
“We were surprised to find such a high amount of C5 in some of the pasta samples,” said Dr. Stuknyt. “We still don’t know what effect this amount could have, but it’s plausible that it could have a potential opioid effect in humans.”
“Release of wheat gluten exorphins A5 and C5 during in vitro gastrointestinal digestion of bread and pasta and their absorption through an in vitro model of intestinal epithelium” by Milda Stuknyt, Margherita Maggioni, Stefano Cattaneo, Paola De Luca, Amelia Fiorilli, Anita Ferraretto and Ivano De Noni (doi:10.1016/j.foodres.2015.04.002). The article has appeared in Food Research International, Volume 72 (June 2015), published by Elsevier. doi:10.1016/j.foodres.2015.04.002