Low- vs high-glycemic index Mediterranean-style eating patterns improved some domains of health-related quality of life but not sleep in adults at risk for type 2 diabetes: The MEDGICarb randomized controlled trial

Abstract

BackgroundA healthy eating pattern such as the Mediterranean-style (MED-HEP) is associated with favorable effects on both cardiometabolic risk markers and self-reported health outcomes. Limited evidence exists regarding the influence of glycemic index (GI) of carbohydrate foods consumed within a healthy eating pattern on self-reported health-status and sleep. ObjectiveTo investigate the effects of a low- vs high-GI MED-HEP on changes in health-related quality of life (HRQoL) and sleep. MethodsThe MedGICarb-intervention trial is a 12-week randomized, controlled, parallel multi-center-trial in adults with at least two features of the metabolic syndrome. Participants consumed an eu-energetic diet profiled as a MED-HEP with either low GI (experimental) or high GI (control). HRQoL and sleep were measured with Medical Outcomes Study 36-Item Short Form Health Survey Version 2 (SF-36v2), Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) at baseline and post-intervention. Results160 adults with ≥ 2 features of the metabolic syndrome completed the intervention (53 % females, age 56 ± 10 y, BMI 31.0 ± 3.1 kg/m2). Low- vs high-GI MED-HEP resulted in differential changes between the groups in the HRQoL domains role physical (5.6 ± 2.2 AU vs -2.5 ± 2.5 AU) and vitality (6.9 ± 1.7 AU vs 0.0 ± 1.8 AU) (p < 0.05), which were driven mostly by improvements in the low-GI group. There were no significant differences between the MED-HEPs for changes in aggregated physical or mental components or for the other individual domains of HRQoL (physical functioning, bodily pain, general health, social functioning, role emotional and mental health) or for sleep quality or daytime sleepiness. ConclusionsLow compared to high GI in the context of a MED-HEP resulted in modest improvements in some, but not all, health domains of HRQoL. No major differences were seen between the groups for measures of sleep. Clinical Trial Registry number and websiteThe trial is registered in the public trial database Clinicaltrials.gov as NCT03410719, https://clinicaltrials.gov/study/NCT03410719?term=NCT03410719&rank=1