The Impact of Vitamin D Deficiency on Modulating of Global DNA Methylation and Obesity-Related Bio-Parameters
Abstract
Background. Obesity has become a rapidly increasing global epidemic health issue where vitamin D seems to impact both of the disease course and the epigenetic profile of the obese individuals. Aim. Given the scarcity of local studies examining the correlation between vitamin D levels, global DNA methylation in the context of obesity, this study was set to explore these potential relationships between VD deficiency and changes in liver enzymes, antioxidant levels, global DNA methylation in addition to body fat distribution as reflected by waist circumference and body mass index in Iraqi obese. Methods. The study involved 90 participants, including 60 obese individuals and 30 healthy controls (mean age: 31.5 years, range: 20-50 years). All the obese cases were diagnosed at Al Karkh General Hospital, Baghdad, Iraq and private clinic during the period of the 1st November 2023 to the 30th March 2024 by the consultant medical staff. Demographic data such as sex, age, BMI, WC, PBF% were assessed in addition to obesity-related bio-parameters, including vitamin D3, liver enzymes (ALP, AST, ALT) and total antioxidant capacity (T-AOC) were evaluated. Furthermore, global DNA methylation levels were assessed following DNA extraction using the MethylFlash™ Global DNA Methylation (5 mC%) ELISA Easy Kit. Results. The levels of vitamin D3 were significantly lower in obese subjects (22.30 ± 1.61) compared to healthy controls (30.20 ± 1.38) (P = 0.002). A positive correlation (r = 0.3) was also observed between lower vitamin D3 levels and reduced global DNA methylation. There was a significant increase in ALT enzyme levels in obese individuals (32.12 ± 2.34) compared to healthy controls (24.47 ± 1.13) (P = 0.02). This suggests that obesity is associated with elevated ALT levels, which are related to liver function. In addition, obese subjects exhibited significantly lower serum T-AOC levels (0.160 ± 0.004) compared to healthy controls (0.191 ± 0.011) (P = 0.0024), indicating a reduction in overall antioxidant defense and a potential increase in oxidative stress. DNA methylation levels were significantly reduced in obese subjects (0.348 ± 0.01) compared to healthy controls (0.559 ± 0.02) (P < 0.0001), suggesting that obesity may be associated with changes in DNA methylation. Conclusion. Vitamin D deficiency is significantly positively correlated with global DNA hypomethylation (5mC%) and reduced total antioxidant capacity (T-AOC) levels. It is also negatively correlated with obesity-related anthropometric measurements and liver enzymes, suggesting its potential role in the increasing rates of chronic inflammation in obese patients and the pathogenesis of obesity.
