Orange juice intake by obese and insulin-resistant subjects lowers specific plasma triglycerides: A randomized clinical trial

Abstract

Background & aims: Dyslipidaemia is usually common in obesity, insulin resistance, and type 2 diabetes mellitus. Clinical trials suggest that orange juice may have a positive impact on lipid metabolism and blood lipid profiles; however conflicting results have been reported. Here, we applied a combined untargeted/targeted lipidomic analysis of plasma to examine the impact of orange (Citrus sinensis) juice intake on the lipidome profile of obese and insulin-resistant subjects.

Methods: Twenty-five participants, both sexes, aged 40-60 years, with obesity and insulin resistance (homeostasis model assessment of insulin resistance (HOMA-IR) index >2.71) ingested 400 mL of orange juice 'Pera' (C. sinensis) for 15 d. Cardiometabolic biomarkers, anthropometric parameters, blood pressure, and plasma lipidomic analysis results were assessed at the beginning and end of the intervention.

Results: After the 15-d intervention, a significant decrease was observed in the diastolic blood pressure and blood lipid profile. Among plasma lipidomes, 316 lipid molecules were identified, with the triglycerides (TGs) subclass being the most abundant (n = 106). Plasma lipidome profiling revealed a major signature of the intervention; with concentrations of 37 TG species decreasing after intervention. Qualitatively, oleic and linoleic acids were among the most prevalent fatty acids linked to the altered TG species, representing 50% of TG chains. Modulated TG species were positively correlated with total TG and very low-density lipoprotein levels, as well as systolic and diastolic blood pressure. A strong inter-individual trend was observed, wherein, compared with less responsive subjects, the high responsive subjects displayed the highest decrease in the concentrations of altered TG species, as as well as systolic blood pressure (decrease of 10.3 ± 6.8 mmHg) and body weight (decrease of 0.67 ± 0.71 kg).

Conclusions: These findings suggest that orange juice has a positive impact on lipid metabolism, mainly regarding the composition of TG-specific fatty acid chains and cholesterol esters, protecting against insulin resistance. Furthermore, lipidomics may help clarify alterations at the molecular level after an intervention, contributing to improve the evaluation of the link between dyslipidaemia, insulin resistance, and nutrition.

Keywords: Insulin resistance; Obese subjects; Orange juice intake; Plasma lipidome profiling; Triglycerides.