Determinants of Oxidative Stress in Orthodox Christian Women: A Comparative Analysis of Monastic and Non-Monastic Lifestyles

Background: Oxidative stress is a key driver of aging and metabolic dysfunction, modulated by diet, lifestyle, and body composition. While structured dietary practices such as intermittent fasting and plant-based regimens have demonstrated antioxidative benefits, the biological impact of long-term religious fasting remains underexplored. Orthodox Christian fasting, characterized by periodic abstention from animal products and alignment with circadian rhythms, offers a unique naturalistic model for examining redox adaptation in humans. Objective:To evaluate predictors of oxidative stress markers in Orthodox Christian monastic women compared to age-matched controls, focusing on the roles of adiposity, insulin, vitamin D status, and age. Methods: In this cross-sectional study, 52 Orthodox nuns and 56 women from the general population were assessed. Serum levels of total antioxidant capacity (TAC), reduced glutathione (GSH), and thiobarbituric acid reactive substances (TBARS) were measured. Anthropometric indices (BMI, body fat percentage, visceral fat), fasting insulin, 25-hydroxyvitamin D [25(OH)D], and age were recorded. Statistical analyses included group comparisons, Spearman correlations, and multivariable linear regression models. Results: In the monastic group, body fat percentage (beta coefficient = 0.387, p = 0.003) and age (beta coefficient = 0.301, p = 0.014) independently predicted TAC, accounting for 28% of its variance. Among controls, insulin positively correlated with GSH (ρ = 0.480, p = 0.0035) and marginally inversely with TAC (ρ = -0.321, p = 0.060). No significant associations were found between 25(OH)D and oxidative markers in either group. Conclusions: Orthodox monastic fasting is associated with enhanced antioxidant capacity and reduced lipid peroxidation, independent of vitamin D or insulin levels. These findings highlight the potential of long-term, culturally structured fasting to modulate redox homeostasis and suggest a complex interplay between age, adiposity, and antioxidant defenses. Further research is needed to elucidate underlying mechanisms and long-term clinical implications.