Effects of hazelnuts consumption on fasting blood sugar and lipoproteins in patients with type 2 diabetes

Background: Previous studies have demonstrated that nuts consumption have beneficial effects on serum lipid profiles in hyperlipidemic or normolipidemic subjects. However, similar studies in diabetes field are quite rare. So, we aimed to investigate the effects of hazelnut consumption on fasting blood sugar (FBS) and lipid profiles in patients with type 2 Diabetes. Materials and Methods: An 8‑week controlled randomized parallel study in patients with type 2 diabetes. Fifty eligible volunteers were assigned to either the control or intervention groups. 10% of total daily calorie intake was replaced with hazelnuts in intervention group. Blood samples were collected from fasting patients at the start and at the end of the study. Results: After 8 weeks, there were significant differences in high‑density lipoprotein‑cholesterol (HDL‑C) concentrations between two groups, using analyses of covariance (P = 0.009), which was due to the larger HDL‑C reduction in control group (P = 0.003). Although, Hazelnut group achieved greater reduction in triglyceride (TG) concentrations than control group, these changes were not statistically significant. Neither between‑group changes nor within‑group changes were significant for FBS, total cholesterol (TC), TG, and low‑density lipoprotein‑cholesterol (LDL‑C) levels. Conclusion: Results of this study indicated that incorporation of hazelnuts into diet can prevent reduction of HDL‑C concentrations in patients with type 2 diabetes, but had no effect on FBS or other lipid profile indices.