Background <p>The possible interaction between dietary carotenoid intake and blood gamma-glutamyl transferase (GGT) levels in patients with stroke has not been well studied. We investigated the effect of the interaction between dietary carotenoid intake and blood GGT levels on the prevalence of stroke.</p> Methods <p>Using data from the National Health and Nutrition Examination Survey 2003–2018, we conducted a cross-sectional study that included individuals residing in the United States and aged ≥60 years. Univariate logistic regression, multivariate-adjusted logistic regression, and restricted cubic spline methods were used to assess the correlation between GGT levels, dietary carotenoid intake, and the prevalence of stroke. Finally, the relative excess risk of interactions, attributable proportion, and synergy index were used to assess additive interactions.</p> Results <p>In total, 11,146 participants were enrolled in this observational study. Logistic regression and restricted cubic spline models adjusted for all covariates revealed that GGT was nonlinearly and positively associated with the prevalence of stroke. In contrast, carotenoid intake was linearly and negatively associated with stroke prevalence. Further, the additive interaction results showed a synergistic effect of low dietary carotenoid intake and high blood GGT levels on the prevalence of stroke.</p> Conclusions <p>For individuals residing in the United States and aged ≥60 years, blood GGT levels were positively correlated and dietary carotenoid intake was negatively correlated with the prevalence of stroke. Low dietary carotenoid intake and high blood GGT levels have a synergistic effect on the prevalence of stroke.</p>