Olive leaf tea is beneficial for lipid metabolism in adults with prediabetes: an exploratory randomized controlled trial

Olive leaves are rich in oleuropein, which has been shown to have beneficial effects on dyslipidemia, type 2 diabetes, and obesity. However, we previously found no significant health benefits of olive leaf tea (OLT) on nonobese and nondiabetic individuals. Thus, we performed this study to further explore the health benefits of OLT in individuals with prediabetes and compare the health benefits between low-concentration OLT (LOLT) and OLT. We hypothesized that OLT will have a more pronounced effect on abdominal obesity as well as glucose and lipid metabolism in prediabetic individuals. Individuals between 40 and 70 years of age with a body mass index of 23.0-29.9 kg/m2 and prediabetes status were recruited and randomly assigned to the OLT or the LOLT group. The intervention, which was the consumption of 330 mL of the test beverage 3 times daily during mealtime, lasted for 12 weeks. After the intervention, serum levels of log-transformed triglycerides (P