## 4 Discussion
In addition, children whose percentage of total energy from UPFs was above 50% showed worse scores for the limitations and inadequate treatment domains of the CD-QOL questionnaire. UPF consumption has a clear negative impact on health, as it is associated with a greater prevalence of overweight, obesity, and cardiometabolic disease and an increased risk of all-cause mortality in adults [17]. The relationships between UPF consumption and diseases can be explain by several mechanisms, including a lower consumption of micronutrients, such vitamins A, B\({}_{12}\), C, E, calcium, zinc, fiber, and polyunsaturated fatty acids, and a higher intake of trans fats, sugars, and sodium [15,16]. Furthermore, this eating pattern negatively affects the gut microbiota through the appearance of intestinal dysbiosis, which can trigger a pro-inflammatory immune response and an increase in intestinal permeability [10]. It is known that gut microbiota disturbance [33] plays a key role in the pathogenesis of CD, as colonizing gut bacteria are critical for the normal development of the host defense [34] and for its metabolic and protective function in the host [35]. Various studies have revealed an alteration in the microbiota of celiac patients compared to the healthy controls, observing a reduction in the population of Lactobacillus and Bifidobacterium and an increase in other bacteria, especially Bacteroides, Escherichia coli, and Clostridium septum [36,37]. Furthermore, a profile of bacterial proteases capable of hydrolyzing gliadin was described in celiac patients that was absent in the healthy controls, confirming a different bacterial proteolytic activity [38]. In this sense, the fact that the CD children in our study had a higher intake of UPFs may have aggravated the pathophysiology of the disease. On the other hand, the fact that CD children consume more UPFs could be due to, but not solely caused by, the characteristics of a poorly completed GFD and, although less likely, a less healthy consumption pattern in this group prior to the onset of the disease due to the relationship of UPFs with the development of intestinal pathologies [10]. In fact, we found that children who consumed less energy from UPFs (i.e., below 50% of their energy) had better redox (lower soluble superoxide dismutase-1 and 15-F2t-isoprostanes) and inflammatory profiles (lower macrophage inflammatory protein-1\(\alpha\)) compared with their counterparts [18]. Regarding mental health, previous studies have associated higher UPF consumption with depression [39,40]. Therefore, given the high consumption of this type of food among our participants [18] and the negative repercussions it may have on their health and quality of life, healthcare professionals should perform an adequate follow-up to assess the presence of UPFs in the diets of these patients. This study has some limitations. Firstly, its cross-sectional design precludes any confirmation of causality. Secondly, the smaller sample sizes for some variables could have prevented the attainment of significance for some associations. Thirdly, the assessment of the participants' quality of life was reported by their parents, which may have differed from the children's own perceptions. However, during childhood, the success of CD treatment and adherence to the GFD depends largely on the parents. Thus, recording their perceptions may be relevant in clinical practice. Fourthly, although it would have been of interest to collect data about the parents' economic income (as it could be related to the children's dietary habits), we included their working status, which could be an indirect measure of their economic position [41,42].