Background and aims: The Nordic diet (ND), is supposed to be associated with a reduced cardiovascular risk; however, clinical trials have led to inconsistent results regarding the effect of this diet on cardio-metabolic markers. Using systematic review and meta-analysis of randomized controlled trials (RCTs), this study aimed to investigate the effect of the ND on circulating levels of total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol, and triglyceride (TG), as well as blood pressure in human adults.
Methods: PubMed, Scopus, ISI Web of Science, and Google Scholar were searched up to February 2018 for relevant articles. Random effects model was used to estimate the overall effects.
Results: Five RCTs consisting of 513 participants were included in the present review. The meta-analysis of five eligible studies showed that ND significantly reduces the total [weighted mean difference (WMD) = - 0.38 mmol/l, 95% confidence interval (CI) - 0.76, - 0.01, P = 0.044] and LDL cholesterol (WMD = - 0.30 mmol/l, 95% CI - 0.54, - 0.06, P = 0.013) levels compared with the control groups; however, none was seen for HDL cholesterol and TG levels. The meta-analysis of four eligible RCTs revealed that the ND significantly reduces the systolic (WMD = - 3.97 mmHg, 95% CI - 6.40, - 1.54, P = 0.001) and diastolic blood pressure (WMD = - 2.08 mmHg, 95% CI - 3.43, - 0.72, P = 0.003).
Conclusion: The Nordic dietary pattern improves blood pressure and also some of blood lipid markers and it should be considered as a healthy dietary pattern.
Keywords: Baltic Sea diet; Blood pressure; Lipid profile; Meta-analysis; Nordic diet; Systematic review.