Nutrients 2020 , 12 , 141
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2. Materials and Methods
2.1. Subjects Between August 2016 and March 2017, overweight and obese subjects with mild hypertension (systolic/diastolic blood pressure: 130–159/85–99 mmHg) were recruited by Atlantia Food Clinical Trials CRO (Cork, Ireland). After screening, healthy persons aged 25–60 years were included if their body weight was stable ( ≤ 5% change over the past 3 months) and their physical activity level was low to moderate (assessed by the International Physical Activity Questionnaire ‐ Short form). Exclusion criteria were use of medications influencing glucose metabolism (e.g., antidiabetics) or EF (e.g., anti ‐ hypertensive and anti ‐ atherosclerotic drugs) and chronic or acute diseases. Smokers, heavy coffee drinkers, and pregnant women were further excluded. Throughout the study, subjects were asked to follow their usual diet and exercise routine and to avoid the named medications that could interfere with the study outcomes. The study protocol was approved by the Clinical Research Ethics Committee of the Cork Teaching Hospitals. All participants gave their written informed consent before the study’s start according to the ICH Guidelines on Good Clinical Practice and the declaration of Helsinki. The trial was registered at clinicaltrials.gov (NCT03986775). 2.2. Study Protocol An outline of the study protocol is depicted in Figure 1. Beside the screening visit, in this double ‐ blinded controlled cross ‐ over trial, participants were tested on two different intervention days, which were separated by a 2–6 ‐ week wash ‐ out period. On the two intervention days, the participants attended the clinic after an overnight fast of at least 10 h. To minimize confounding variables, for premenopausal women, the intervention days were within the first seven days of their menstrual cycle. Moreover, the subjects were asked to avoid high ‐ fat and high ‐ flavonoid foods (e.g., blueberries, dark chocolate, etc.) for 24 h and caffeine for 10 h and to abstain from exercise for 12 h before the intervention.
Figure 1. Outline of the study protocol. FMD, flow ‐ mediated dilation; ISO, citrus drink containing 50 g of isomaltulose; SUC, citrus drink containing 50 g of sucrose.
The order of the assessments was exactly the same on both intervention days. Prior to carbohydrate load (T0), a brachial ultrasound FMD scan was performed, with blood drawn shortly thereafter. All subjects were blinded to treatment and randomly assigned to consume either 50 g of isomaltulose (Palatinose™, provided by BENEO GmbH, Mannheim, Germany) or 50 g sucrose in the form of instant citrus drinks. Therefore, drink powders were dissolved in 500 mL of water shortly before consumption. The subjects were instructed to consume the citrus drink within 10 min after the
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