Dietary Antioxidant Capacity and Serum Antioxidant Status in Men with Coronary Artery Disease: An Exploratory Case–Control Study

Background: Oxidative stress, dietary antioxidant intake, and body fat distribution have been implicated in the development and progression of coronary artery disease (CAD). However, studies simultaneously evaluating serum oxidative status, dietary total antioxidant capacity (DTAC), nutritional status, and angiographically determined CAD severity remain scarce. Therefore, this study aimed to comprehensively investigate these parameters and their associations in men with angiographically confirmed CAD. Methods: This hospital-based case–control study included 80 men aged 25–65 years, comprising 40 patients with angiographically confirmed CAD and 40 angiographically normal controls. Dietary intake was recorded using three-day dietary records, and an antioxidant food frequency questionnaire (FFQ) was also administered. Dietary total antioxidant capacity (DTAC) was calculated separately from the three-day dietary records and the FFQ using ferric reducing antioxidant power (FRAP) values. Anthropometric and body composition measurements, routine biochemical parameters, serum total antioxidant status (TAS), and total oxidant status (TOS) were assessed. CAD severity was quantified using the Gensini score. Multivariable binary logistic regression was performed to examine factors associated with CAD status. Results: Compared with controls, participants with CAD had significantly higher fasting blood glucose, AST, ALT, total cholesterol, LDL-cholesterol, neck circumference, body fat percentage, and visceral fat level, whereas HDL-cholesterol, dietary antioxidant capacity assessed by FFQ, saturated fat intake, cholesterol intake, and n–3 fatty acid intake were significantly lower (all p < 0.05). Serum TOS differed significantly between groups, whereas TAS did not. Among patients with CAD, Gensini score was negatively correlated with energy intake (r = −0.439, p = 0.005), fat intake (r = −0.407, p = 0.009), and MUFA intake (r = −0.398, p = 0.011), and positively correlated with waist-to-hip ratio (r = 0.331, p = 0.037). In the multivariable logistic regression model, higher DTAC–FFQ and HDL–C were independently associated with lower odds of CAD, whereas higher fasting blood glucose was associated with higher odds of CAD. Each one-mmol increase in DTAC-FFQ was associated with 36.7% lower odds of CAD (OR = 0.633, 95% CI: 0.479–0.835), while each 5 mg/dL increase in HDL-C was associated with 32.4% lower odds (OR = 0.676, 95% CI: 0.512–0.893). In contrast, each 10 mg/dL increase in fasting blood glucose was associated with 47.2% higher odds of CAD (OR = 1.472, 95% CI: 1.069–2.027). Waist-to-hip ratio was not independently associated with CAD status. Conclusions: Men with angiographically confirmed CAD exhibited FFQ-derived dietary total antioxidant capacity despite similar serum antioxidant status. In this exploratory case–control study of men, higher dietary antioxidant capacity and HDL-C were independently associated with lower odds of CAD, whereas higher fasting blood glucose was associated with higher odds. These findings suggest an association between dietary antioxidant capacity, cardiometabolic factors, and CAD status; however, the cross-sectional nature of the assessment precludes causal inference, and larger prospective studies are needed to confirm these associations.