Effects of n-3 fatty acid supplements on glycemic traits in Chinese type 2 diabetic patients: A double-blind randomized controlled trial

Scope To investigate the effects of n‐3 fatty acid supplements, both marine and plant‐based, on glycemic traits in Chinese type 2 diabetes patients. Method and results In a double‐blind randomized controlled trial, 185 recruited Chinese type 2 diabetes patients were randomized to either fish oil (FO, n = 63), flaxseed oil (FSO, n = 61), or corn oil group (served as control group, n = 61) for 180 days. The patients were asked to take corresponding oil capsules (four capsules/day), which totally provided 2 g/day of eicosapentaenoic acid + docosahexaenoic acid in FO group and 2.5 g/day of alpha‐linolenic acid in FSO group. No group × time interaction was observed for homeostatic model assessment of insulin resistance, fasting insulin, or glucose. Significant group × time interaction (P = 0.035) was observed for glycated hemoglobin A1c (HbA1c), with HbA1c decreased in FO group compared with corn oil group (P = 0.037). We also found significant group × time interactions for lipid traits, including LDL cholesterol (P = 0.043), total cholesterol (P = 0.021), total cholesterol/HDL cholesterol (P = 0.009), and triacylglycerol (P = 0.003), with the lipid profiles improved in FO group. No significant effects of FSO on glycemic traits or blood lipids were observed. Conclusions Marine n‐3 PUFA supplements may improve glycemic control and lipid profiles among Chinese type 2 diabetic patients. A randomized control trial is designed to investigate the effect of fish oil and flaxseed oil supplements on glucose‐related traits in 185 Chinese patients with type 2 diabetes. Patients were randomly assigned to daily take fish oil, flaxseed oil, and corn oil capsules (as a control) for 180 days (four capsules/day). The trial found that fish oil supplements may improve both of the glycemic control and lipid profiles among Chinese type 2 diabetic patients.