Changes in Oxidative Stress, Inflammatory Markers, and Lipid Profile After a 6-Week High-Antioxidant-Capacity Dietary Intervention in CVD Patients

<b>Background/Objectives</b>: Increased dietary antioxidant capacity is a good means of lowering oxidative stress and cardiovascular risk. Established antioxidant capacity doses should be tested using dietary intervention. <b>Methods</b>: We analysed the influence of a high-antioxidant-capacity diet on oxidative stress (OS) and inflammatory and lipid profile in CVD (cardiovascular disease) subjects with initially low (LowA) and high (HighA) antioxidant capacity markers. It was an experimental study with a 6-week dietary intervention (DI). Forty-eight CVD patients completed the DI. Blood and urine samples were collected, and anthropometric measurements were taken. Dietary data were collected using a multi-day food record method. α-tocopherol, β-carotene, and retinol were chosen as antioxidant capacity markers; F2-isoprostanes (F2-IsoP), oxidised low-density lipoproteins (oxLDL), and uric acid (UA) were used as OS markers; and interleukin 6 (IL-6) and high-sensitivity <i>C</i>-reactive proteins (hs-CRP) were used as inflammatory markers. Total cholesterol, low- and high-density lipoproteins, and triglycerides (TCHOL, LDL, HDL, TRI) as lipid profiles were analysed. Two groups of subjects with LowA and HighA profiles were identified. <b>Results</b>: The total dietary antioxidant capacity intake during DI was increased by 56%. In the total sample, the DI increased β-carotene, retinol, and UA, and decreased IL-6 oxLDL. The LowA group exhibited increased β-carotene, α-tocopherol, retinol, and decreased IL-6. The HighA group exhibited increased β-carotene and decreased IL-6, F2-IsoP, oxLDL, and oxLDL/LDL ratio. In the HighA group, compared to the LowA group, greater decreases in α-tocopherol and F2-IsoP were found. In both groups, inflammatory markers (IL-6) decreased, and β-carotene increased. <b>Conclusions</b>: The DI results depended on the antioxidant capacity profile at baseline; nevertheless, the established DI including selected antioxidative snacks significantly decrease oxidative stress and improve antioxidant capacity. Further research on diet natural antioxidant supplementation needs to be continued.