Mutual Impact of Dietary Antioxidants and rs1800629 on Insulin Levels in Adults with Obesity.

The interplay between genetic factors and nutritional patterns is critical in understanding metabolic health. This analysis evaluated the potential reciprocal relationships between the -308 G/A gene polymorphism, the Composite Dietary Antioxidant Index (CDAI), and insulin-related variables in Spanish adults with obesity. A cross-sectional analysis was conducted in 292 adults with obesity. Anthropometric, biochemical, and dietary variables were assessed. -308 G/A genotyping was performed. Associations and potential interactions between CDAI and genotype on insulin and homeostatic model assessment for insulin resistance (HOMA-IR) were examined using multivariate regression and two-way ANOVA. Higher CDAI scores were significantly associated with lower insulin levels ( < 0.001) and HOMA-IR ( < 0.001), regardless of genotype. Carriers of the A allele (GA/AA) showed a non-significant trend toward higher insulin levels ( = 0.087) and a steeper decrease in insulin levels with increasing CDAI, with a significant interaction observed between genotype and CDAI (interaction = 0.003). Multivariate analyses confirmed that CDAI and genotype were independently associated with insulin and HOMA-IR levels. However, interaction terms were not consistently significant across all models. These findings emphasize the potential of antioxidant-rich diets to help modulate the influence of pro-inflammatory genotypes on insulin resistance, highlighting the relevance of integrating genetic and dietary factors in managing obesity-related metabolic risks. Further studies are warranted to confirm these preliminary findings and to better understand the mechanisms underlying gene-diet interactions in metabolic regulation.