Alireza Zimorovat - Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Amin Salehi-Abargouei - Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Mohammad Mohammadi - Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Nahid Ramezani-Jolfaie - Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

Background and Aim: Dietary interventions are important to improve blood glucose control. The Nordic diet (ND) encourages consuming whole grains, fruits, vegetables, fish, low dairy products which might has a beneficial role in glycemic control, however the findings are inconsistent.To determine efficacy of the Nordic dietary pattern for improving glycemic control, we conducted the present systematic review and meta-analysis.Methods: We conducted a systematic review and random effects meta-analysis of randomized controlled trials, including publications in PubMed, Web of Science, Scopus and Google Scholar until May 2018. The risk of bias was also assessed using the Cochrane collaboration s tool.Results: Six studies totaling 618 participants were identified and all of them had low risks of bias. Although there was no considerable change in fasting plasma glucose [weighted mean difference (WMD) = -0.05 mmol/l, 95% confidence interval (CI): -0.13, 0.01, P = 0.112], a significant reduction in insulin levels with following the ND was observed (WMD = -1.12 mU/l, 95% CI: -1.84, -0.39, P = 0.002). A significant decrease in homeostasis model assessment for insulin resistance (HOMA-IR) index was also demonstrated (WMD = -0.34, 95% CI: -0.53, -0.14, P = 0.001). This dietary pattern did not significantly affect 2-h post-prandial blood glucose and Matsuda index.Conclusion: Adherence to the ND can improve insulin resistance among patients with glucose intolerance and type 2 diabetes.

Nordic Diet; Baltic Sea Diet; Glucose; Insulin; Systematic Review