Dr. Uusitupas first study compared the effects of a gluten-free diet and a gluten-free diet that included oats with a randomized trial involving 92 adult celiac patients: 45 in the oats group whose intake averaged approximately 34 grams per day, and 47 patients in the control group. Patients in the oats group were allowed to eat oats freely in conjunction with an otherwise gluten free diet. After five years 35 patients in the original oats group, 23 of whom were still eating oats at least twice a week, and 28 in the control group that was on a conventional gluten free diet were examined. The results confirmed that eating oats did not cause ANY duodenal mucosal damage to the adult celiac patients in the study. Further, the patients were also examined using histological, histomorphometric, and immunological methods, and AGA, ARA, and EMA serological test results of those in the oat group showed no negative effects that could be linked to eating oats.
According to Dr. Uusitupa, the high antibody levels that appeared in some of the patients that were in both groups are most likely explained by poor compliance to a gluten free diet, and the reason why celiac patients can tolerate oats must be based on structural differences between the proteins of oats, wheat, barley, and rye. The toxic portion of the harmful gluten protein lies in the ethanol soluble fraction called gliadins, whose toxicity remains after digestion. With oats, however, it is possible that the absence of specific amino acid sequences that are found in wheat gliadin but are not found in oat avenin allow oats to be tolerated by celiacs. Last, the researchers note that taking oats off of the list of forbidden cereals might improve patient compliance to the gluten-free diet by giving them more food choices.