A gluten-free diet (GFD) is the only treatment available for celiac disease (CD); hence, it is important to ensure correct adherence to the diet and adequate monitoring of the diet. The present study aims to assess the importance of an early follow-up of celiac patients after diagnosis of the disease, identify the role of stool gluten immunogenic peptides (GIPs) in the assessment of GFD adherence, and analyze possible nutritional imbalances or deficiencies in the GFD. This is a cross-sectional study carried out in pediatric patients with newly diagnosed CD in a tertiary hospital in Spain. Of the 61 patients included, 14% had positive stool GIPS at 4 months after CD diagnosis, Among them, 88% had negative stool GIPS at 9 months after diagnosis, following dietary advice. We found nutritional deficiencies in the GFD, such as vitamin D (with only 27% of patients with adequate intakes), folate, calcium, magnesium, and fiber. Similarly, we found imbalances: excess protein and fat intakes and a high percentage of total daily energy intake came from ultra-processed foods (UPF). These findings emphasize the importance of early follow-up of children after diagnosis of CD. It is also crucial to identify patients with poor GFD compliance based on stool GIPS and analyze GFD nutritional imbalances and deficits. Our findings may contribute to the development of specific strategies for the early follow-up of patients with CD, including appropriate nutritional counselling.

Celiac disease (CD) is included in the group of complex or multifactorial diseases, i.e., those caused by the interaction of genetic and environmental factors. Despite a growing understanding of the pathophysiological mechanisms of the disease, diagnosis is still often delayed and there are no effective biomarkers for early diagnosis. The only current treatment, a gluten-free diet (GFD), can alleviate symptoms and restore intestinal villi, but its cellular effects remain poorly understood. To gain a comprehensive understanding of CD’s progression, it is crucial to advance knowledge across various scientific disciplines and explore what transpires after disease onset. Metabolomics studies hold particular significance in unravelling the complexities of multifactorial and multisystemic disorders, where environmental factors play a significant role in disease manifestation and progression. By analyzing metabolites, we can gain insights into the reasons behind CD’s occurrence, as well as better comprehend the impact of treatment initiation on patients. In this review, we present a collection of articles that showcase the latest breakthroughs in the field of metabolomics in pediatric CD, with the aim of trying to identify CD biomarkers for both early diagnosis and treatment monitoring. These advancements shed light on the potential of metabolomic analysis in enhancing our understanding of the disease and improving diagnostic and therapeutic strategies. More studies need to be designed to cover metabolic profiles in subjects at risk of developing the disease, as well as those analyzing biomarkers for follow-up treatment with a GFD.

Background/Objectives: Celiac disease (CD) alters nutrient absorption and body composition, especially during childhood. Although adherence to a gluten-free diet (GFD) promotes mucosal recovery, its impact on cellular functionality and metabolic balance remains underexplored. This study aims to evaluate the utility of bioelectrical impedance vector analysis (BIVA) in assessing nutritional status, inflammatory improvement, and body composition changes in pediatric patients with CD following a GFD. Methods: Seventy-nine children aged 5–14 years were studied. Three groups were analyzed: (1) 25 children with newly diagnosed CD, evaluated at diagnosis and after 12 months of GFD (prospective cohort); (2) 25 CD patients on a GFD for over 24 months (cross-sectional); and (3) 29 healthy controls. Body composition (fat mass (FM), fat-free mass (FFM), body cell mass (BCM), phase angle (PhA), and Na⁺/K⁺ ratio) was measured. GFD adherence was assessed and a dietary assessment was also performed. Results: After 12 months on a GFD, newly diagnosed CD patients showed significant increases in FM (from 8.2 to 10.1 kg, p = 0.001), FFM (p = 0.001), and BCM (p = 0.0001), along with a significant decrease in the Na⁺/K⁺ ratio (p = 0.015). Compared to healthy controls, CD children on GFD for more than 24 months had higher FM (12.2 vs. 8.8 kg, p = 0.013) and lower Na⁺/K⁺ ratios (p = 0.006). PhA increased slightly over time but did not reach statistical significance. Conclusions: Our study suggests that the adherence to a GFD leads to improved body composition and cellular homeostasis in children with CD, as reflected by increases in BCM and reductions in Na⁺/K⁺ ratio, making it a promising biomarker for monitoring inflammation and cellular recovery.

Background/Objectives: Celiac disease (CD) is a complex multifactorial disorder driven by genetic susceptibility and environmental triggers, with ultra-processed foods (UPFs) acting as potential disruptors of immune homeostasis. This study aimed to characterize the patterns and temporality of UPF consumption in a pediatric population with CD to provide evidence-based insights that can optimize the nutritional quality of a gluten-free diet (GFD) beyond mere gluten avoidance. Methods: A total of 128 children aged 5–14 years were enrolled, comprising a baseline cohort of 48 children newly diagnosed with CD (pre-GFD), 88 patients who had followed a GFD for at least 6 months (post-GFD), including 44 participants from the pre-GFD cohort prospectively re-evaluated after 12 months and 44 additional patients with established GFD adherence and a control group of 36 healthy children (CTRL). Dietary intake was assessed using three-day 24 h recalls. Food processing levels were determined using the NOVA classification system, and adherence to the Mediterranean Diet was evaluated via the KIDMED index. Results: At baseline, UPFs (NOVA 4) were the primary daily energy source for both celiac patients and controls, accounting for over 57% of total caloric intake, peaking during breakfast (~74%) and afternoon snacks (~81%). Longitudinal analysis showed that the nutritional profile and global UPF consumption remained remarkably stable after 12 months on a GFD, though a significant increase in vitamin B6 intake was observed (0.9 ± 0.4 vs. 1.1 ± 0.5 mg; p = 0.034). However, meal-pattern shifts occurred over the 12 months: celiac children significantly reduced their daily intake of culinary ingredients (NOVA 2; p = 0.029) and processed foods (NOVA 3; p = 0.025). Compared to healthy controls, post-GFD patients exhibited significantly lower Vitamin D intakes (4.6 ± 9.4 vs. 6.2 ± 12.3 µg/day; p = 0.008), meeting only 30.8% of the reference intake. Both groups presented inadequate intakes of iron, calcium, folate, magnesium, and zinc. Conclusions: Pediatric celiac patients exhibit a high, deeply ingrained consumption of UPFs that mirrors healthy controls and persists 12 months after starting a GFD. While the GFD alters meal processing dynamics, it fails to resolve baseline micronutrient insufficiencies and is associated with lower dietary vitamin D intake, highlighting the urgent need for targeted nutritional interventions that focus on whole food quality rather than just gluten elimination.