Phytochemicals are bioactive compounds found in plant-based foods. Consumption of phytochemical-rich foods has been associated with cardiovascular and metabolic diseases prevention in various populations. To quantify the phytochemical content of the diet, dietary phytochemical index (DPI) was established which is defined as the proportion of daily energy intake derived from foods rich in phytochemicals. The purpose of this study was to evaluate the association between the DPI and oxidative stress markers and cardiovascular risk factors in obese adults. In this cross-sectional study, a total of 140 adults aged 20–60 years and body mass index (BMI) of ≥ 30 kg/m2 were included. A validated food frequency questionnaire (FFQ) was used to collect information on dietary intakes. The DPI was calculated based on the following formula: DPI = [daily energy obtained from foods rich in phytochemicals (kcal)/total daily energy intake (kcal) × 100]. There was an inverse association between DPI and serum concentrations of Malondialdehyde (MDA) (P = 0.004), triglyceride (TG) (P-trend = 0.003), high-sensitive C-reactive protein (hs-CRP) (P = 0.017), and erythrocyte superoxide dismutase (SOD) activity (P = 0.024). Total antioxidant capacity (TAC) was positively associated with DPI score (P = 0.045). No significant relationship was found between the DPI score and fasting blood sugar (FBS), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total oxidant status (TOS), glutathione peroxidase (GPx), catalase (CAT), and anthropometric parameters as well as systolic and diastolic blood pressure. The current study found that there was a significant inverse association between DPI and oxidative stress, inflammation, and hypertriglyceridemia as cardiovascular disease (CVD) risk factors in obese population. However, further research is needed to confirm these findings.

Background Metabolic syndrome is recognized as one of the most common global health issues, which may cause numerous side effects. Studies have shown the favorable effects of probiotic supplements on glycemic indices, lipid profiles, and oxidative stress status. However, the number of studies investigating the effects of food products containing probiotics and prebiotics on metabolic diseases is limited. Limited evidence also shows that products containing Lactobacillus plantarum could affect metabolic alterations in chronic diseases. No previous study evaluated the impact of synbiotic yogurt containing Lactobacillus plantarum on people with metabolic syndrome. Therefore, the current study aims to investigate the effect of the newly developed synbiotic yogurt containing Lactobacillus plantarum, Lactobacillus pentosus, and Chloromyces marcosianos yeast on the components of metabolic syndrome, oxidative stress status, and some other risk factors for cardiovascular diseases in adults with metabolic syndrome. Methods In this study, 44 patients with metabolic syndrome will be randomly assigned to intervention and control groups in a randomized, double-blind, controlled clinical trial. Participants in the intervention group will consume 300 g of synbiotic yogurt daily, while those in the control group will consume 300 g of regular yogurt daily for 12 weeks. Anthropometric measurements, blood pressure, and biochemical parameters will be evaluated before and after the intervention. Discussion The management of the metabolic syndrome presents significant clinical challenges. While probiotic supplementation for these individuals has been considered, the consumption of probiotic-rich foods has received considerably less attention. Trial registration number Iranian Registry of Clinical Trials (IRCT20220426054667N1) (2022–05-18).