Effects of Body Mass Index (BMI), Dietary Intake and Serum Antioxidant Vitamin Concentration on Urinary 8-hydroxydeoxyguanosine and F₂-isoprostane Excretions

Objective: The objective of this study was to identify the optimal BMI and desirable dietary habits for reducing oxidative stress and thereby slowing aging and preventing chronic diseases. We examined the relationships between urinary 8-hydroxydeoxyguanosine (8-OHdG) and F2-isoprostane excretions with BMI, dietary intakes and serum antioxidant vitamin concentrations. Method: The subjects were 15 people undergoing an Anti-Aging checkup (average age 64.9 [42-79], average BMI 23.2[16.0-31.6]).Exclusion criteria included a history of cancer, cardiovascular disease, stroke, diabetes, and current smoking. The serum parameters examined were α-carotene, β-carotene, vitamin C and vitamin E, the urinary parameters were 8-OHdG and F2-isoprostane and the dietary intake parameters were energy, carbohydrate, fat, protein, α-carotene, β-carotene, vitamin C, vitamin E and fruit and vegetable. Results: The relationships between urinary 8-OHdG and F2-isoprostane excretions and BMI both followed a quadratic curve with the lowest levels at BMI 23 (8-OHdG: R²= 0.749, F2-isoprostane: R² = 0.519). Multiple linear regression analysis showed that important variation factors for urinary 8-OHdG excretion were BMI and carbohydrate/energy ratio (R²= 0.826). Important variation factors for urinary F2-isoprostane excretion were BMI and serum vitamin E concentration (R²=0.613). Conclusion: The relationships between urinary 8-OHdG and F2-isoprostane excretions and BMI both followed a U-shaped curve with the lowest levels at BMI 23.