Nutrients

Background: Autoimmune diseases (AIDs) are characterized by chronic inflammation and tissue damage resulting from abnormal immune responses. While genetic and environmental factors play significant roles in disease development, essential micronutrient deficiencies (MNDs) represent a critical and often overlooked contributor. Methods: This review examines the interactions between micronutrients and immune cells, focusing on vitamin D, vitamin B12, folate (FA), and iron, and their roles in AIDs, such as rheumatoid arthritis, autoimmune thyroid disorders, multiple sclerosis, systemic lupus erythematosus, and other connective tissue diseases. We explore the immunomodulatory effects of these micronutrients, their impact on immune tolerance, and the mechanisms by which MNDs contribute to disease progression. Results: MNDs are commonly observed in patients with AIDs and are associated with worsening immune dysregulation, increased inflammation, and disease severity. Vitamin D plays a pivotal role in modulating immune responses and attenuating inflammation, while iron and FA are essential for immune cell proliferation and function. Vitamin B12 supports methylation processes and genomic stability. Conclusions: MNDs significantly influence the pathogenesis and progression of AIDs. Routine micronutrient screening and targeted supplementation should be considered as part of clinical management, offering potential adjunctive benefits alongside conventional therapies. Further research is needed to define optimal dosing strategies and to identify patient subgroups most likely to benefit from nutrition-based interventions.

Background/Objectives: This study examined the relationship between adherence to the Mediterranean diet (MD), dietary and vitamin intake, physical activity, and body composition in young adults. Methods: A total of 145 Spanish university students (34 women and 111 men) were included in this cross-sectional study, with a mean body mass index (BMI) of 23 kg/m². MD adherence was assessed using the Mediterranean Diet Adherence Screener (MEDAS). Dietary intake was evaluated through a three-day food record, physical activity using the International Physical Activity Questionnaire (IPAQ), and body composition by bioelectrical impedance analysis. Results: Overall adherence to the MD was moderate. Participants with high MD adherence showed significantly lower body weight (p < 0.05; d = 0.4), BMI (p < 0.01; d = 0.52), fat mass (p < 0.05; d = 0.44), and fat mass percentage (p < 0.05; d = 0.38) compared with those with low adherence. Energy (p < 0.05; d = 0.41), protein (p < 0.05; d = 0.65), and carbohydrate (p < 0.05; d = 0.37) intake per kilogram of body weight were higher in the high-adherence group. Fiber intake was greater (p < 0.001; d = 0.82) among those with higher MD adherence. Adherence to the MD was also associated with higher intakes of vitamins C (p < 0.05; d = 0.39) and E (p < 0.05; d = 0.62), retinol equivalents (p < 0.05; d = 0.28), and carotenoids (p < 0.001; d = 0.79). MD adherence was inversely correlated with body weight (r_s = −0.32; p < 0.01; r = 0.46) and BMI (r_s = −0.34; p < 0.01; r = 0.32). Fiber intake showed positive correlations with several water-soluble vitamins, particularly folate (HAG: r_s = 0.68; p < 0.001; r = 0.81 and LAG: r_s = 0.61; p < 0.001; r = 0.69). Conclusions: In conclusion, higher adherence to the MD among university students was associated with healthier body composition and improved vitamin intake adequacy. These findings support the promotion of the MD as an effective nutritional strategy to enhance micronutrient intake and overall diet quality in young adults.

Background/Objectives: Zinc is an essential trace element involved in multiple aspects of immune function, including epithelial barrier integrity, innate and adaptive immune responses, regulation of inflammation and oxidative stress. Zinc deficiency has been associated with increased susceptibility to infections, particularly in the pediatric population. This narrative review aims to summarize and discuss current evidence on the role of zinc in the prevention and management of pediatric respiratory infections. Methods: A comprehensive literature review was conducted including randomized controlled trials, real-world studies, and international guidelines published in recent years. Both zinc monotherapy and multicomponent dietary supplements containing zinc were considered. Results: Evidence consistently supports a preventive role of zinc supplementation in reducing the incidence and burden of respiratory infections, particularly in children with recurrent disease and in zinc-deficient populations. Zinc-containing multicomponent supplements demonstrated significant reductions in infection frequency and duration, alongside improved patient and parent-reported outcomes, with a favorable safety profile. In contrast, data on zinc as an adjunctive treatment during acute infections, especially severe pneumonia, are less consistent, with limited impact on major clinical outcomes. The effectiveness of zinc appears to be influenced by treatment duration, baseline nutritional status, and formulation. Conclusions: In conclusion, zinc may represent a valuable component of preventive immune-nutritional strategies for pediatric respiratory infections, especially when administered as part of multicomponent formulations and over prolonged periods. While its role in acute disease management remains uncertain, optimizing zinc status may contribute to reducing infection recurrence and overall disease burden. Further well-designed trials are warranted to clarify optimal dosing, timing, and target populations.