Food may induce inflammation and favor development of metabolic diseases, which have been associated with increased inflammation and potential risk of cognitive impairment. It is customary to know whether food or disease promote inflammation. Our hypothesis was that Okinawan-based Nordic (O-BN) diet leads to decreased circulating concentrations of inflammatory and neural biomarkers. The objectives of this study were to examine the effects of the O-BN diet on inflammatory and neural responses. First, 2 different breakfasts; one standard and another O-BN-based, were given in random order to 19 healthy volunteers. Second, a 12-week O-BN-dietary intervention was performed in type 2 diabetes mellitus (T2DM), where the participants were followed for another 16-weeks, with registration of anthropometry and metabolic parameters. Non-diabetic subjects served as controls at baseline. Plasma was analyzed for cytokines by a 10-plex Luminex assay and neurofilament light (NfL) by an ultrasensitive Single molecule assay. Cytokine levels decreased after a single breakfast intake, independent of diet composition. Cytokine levels were higher in T2DM than in controls. Anthropometric and metabolic parameters were improved by the dietary intervention. In parallel, cytokine levels were lowered, although only significantly for IL-18 (P = .001), with a tendency of significance for IL-12p70 (P = .07). Levels of IL-18 correlated with glucose, HbA1c and lipids, but not with body mass index, insulin or blood pressure. NfL levels increased during the intervention (P = .049). O-BN-based diet does not affect postprandial cytokine levels in health, whereas it renders decreased circulating IL-18 levels along with metabolic biomarkers in T2DM, with no beneficial effect on NfL.