BACKGROUND: We studied the link between adherence to a low carbohydrate diet (LCD) and metabolic syndrome (MetS) and its components in Iranian population. METHODS: In this cross-sectional study, a validated 65-item food frequency questionnaire was used to collect dietary intakes from 3847 Iranian adults aged 35 to 65 years. These intakes were then used to calculate the LCD scores. The definition of metabolic syndrome followed the guidelines provided by the American Heart Association/National Heart, Lung and Blood Institute (AHA/NHLBI). To explore the association between LCD and MetS, multivariate logistic regression was employed in three models. RESULTS: After accounting for potential confounding factors, individuals in the highest quartile of LCD score demonstrated a lower probability of having MetS compared to those in the lowest quartile (OR: 0.70
95% CI: 0.56-0.88). When the analyses were performed for components of MetS, we found that compared to individuals in the bottom quartile, those in the top quartile of LCD score had a lower odds of enlarged waist circumference (OR: 0.62
95% CI: 0.49-0.79), low serum HDL cholesterol (OR: 0.75
95% CI: 0.62-0.92) and elevated blood pressure (OR: 0.71
95% CI: 0.57-0.88). Regarding other components of MetS, no significant association was seen between LCD score and high serum triacylglycerol concentrations and abnormal glucose homeostasis. CONCLUSIONS: We found that adherence to a LCD was inversely related to MetS and its components including low serum HDL-C, elevated blood pressure, and enlarged waist circumference. CLINICAL TRIAL NUMBER: Not applicable.