Availability of dietary secoisolariciresinol diglucoside on borderline blood cholesterol level in men: A randomized, parallel, controlled, double-blinded clinical trial

Borderline low-density lipoprotein cholesterol (LDL-C) levels (120-139 mg/dL) increase the risk of cardiovascular disease. Therefore, the use of functional dietary nutrients is expected to control blood LDL-C levels. This study aimed to evaluate the effect of dietary secoisolariciresinol diglucoside (SDG) on blood cholesterol in healthy adults with borderline LDL-C levels. A randomized, parallel, controlled, double-blinded clinical trial was performed for participants with borderline LDL-C levels, for 12 weeks with SDG (60 mg/day) or placebo. Lipid profile [LDL-C, high-density lipoprotein cholesterol (HDL-C), LDL-C/HDL-C ratio, total cholesterol (TC), and triglycerides] and liver disease risk markers were measured at weeks 0, 4, 8, and 12. Analyzing 36 participants in each group revealed a significant interaction between treatment and time, indicating reduced LDL-C (p = 0.049) and TC (p = 0.020) levels in SDG-receiving men but not women. However, no significant differences were observed in other markers regardless of gender. The results suggest that a daily intake of 60 mg of SDG lowers LDL-C and TC levels in men with borderline LDL-C, proposing SDG's potential as a functional dietary nutrient for cardiovascular disease prevention. This study was registered in the UMIN-CTR database (UM1N000046202).