Effect of Citrus Flavonoids on Obesity.

The aim of this study is to evaluate whether the intake of a functional juice enriched in citrus polymethoxylated flavonoids is able to improve the glycaemic profile and insulin resistance of obese patients by reversing the associated oxidative and inflammatory stress, as well as the differential alteration of the intestinal microbiota. To achieve this, a prospective, randomised, double-blind, placebo- controlled, clinical-baseline intervention study will be conducted in obese patients (BMI=30-40 kg/m2) with type 2 diabetes (DM2) (n=40) and obese patients without alterations in carbohydrate metabolism (n=40). Each of these groups will be randomly divided into 2 subgroups (n=20), one of which will receive polymethoxyflavonoid-enriched orange juice (14%: nobiletin, sinensetin, tangeretin) (200 ml/ day) and the other group will receive the corresponding placebo juice for 8 weeks. In addition, all of them will receive a hypocaloric diet. Anthropometric parameters, body composition and nutritional status will be assessed, cardiovascular risk factors and comorbidities will be studied (HT, SAHS, dyslipidaemia, insulin resistance), oxidative stress parameters will be compared (total and mitochondrial ROS production, mitochondrial membrane potential, glutathione levels by static cytometry and mitochondrial respiration rate by Seahorse flow analyser), antioxidant enzymes (SOD, GPx) and molecular oxidation products (Carbonyl proteins and 8-oxo-dG, LDLox) and LPS by ELISA techniques, inflammatory parameters (IL6, TNFa, IL1b, adiponectin, PAI-1, IL10) by Luminex XMAP technology in serum. Metabolomic analysis will also be performed in plasma (NMR spectroscopy and PLS-DA), and the content and diversity of the gut microbiota (16S rRNA amplicons, and direct metagenomic sequencing, with Illumina MiSeq technology) will be assessed in faeces, before and after the dietary intervention. Individualised dietary follow-up and assessment of subjects' quality of life will be carried out.