The Effect of Citric Flavonoid on Endothelial Function

Inclusion Criteria: * Overweight men/women (BMI 25-35 kg/m2) * Healthy individuals * Age between 18 and 70 years * Fasting glucose \< 7.0 mmol/L * Normal HbA1c (4.4 to 6.2%) Exclusion Criteria: * Type 2 diabetes mellitus (defined as fasting plasma glucose ≥ 7.0 mmol/L) * Gastroenterological diseases or abdominal surgery * Cardiovascular diseases, cancer, liver or kidney malfunction, thyroid disorders, disease with a life expectancy shorter than 5 years * Self-admitted HIV-positive status * Abuse of products; alcohol (\> 20 alcoholic consumptions per week) and drugs * Smoking * Plans to lose weight or following a hypocaloric diet during the study period * Weight gain or loss \> 3 kg in previous 3 months * Use of medication interfering with endpoints * Intake of antihypertensive medication, statins, corticosteroids, NSAIDs, ciclosporin A, rifampicin are strictly forbidden * Use of antioxidants, minerals and vitamin supplements available in pharmacies, drugstores, food markets or in alternative medicine * Hormone replacement therapy (women) * Use of antibiotics in the 90 days prior to the start of study * Administration of investigational drugs or participation in any scientific intervention study which may interfere with this study (to be decided by the principle investigator) in the 180 days prior to the study * Known pregnancy (assessed by a pregnancy test before start of study), lactation * Blood donation within 3 months before study period * Failure to comply prohibited intake of hesperidin containing food products during study period and prohibited intake of food products that are able to influence the FMD measurements one day prior to test days. * History of any side effects towards the intake of flavonoids or citrus fruits