Time-Restricted Eating in Combination With a Low Glycaemic Index Diet on Cognitive Function, Biological Ageing and Metabolic Health in Perimenopause and Menopause.

Overview

The goal of this randomised controlled trial is to investigate whether Time-Restricted Eating (TRE) combined with a Low Glycaemic Index Mediterranean Diet can improve cognitive function, metabolic health, and biological ageing in late perimenopausal and menopausal women aged 45-75 years with a BMI ≥23 kg/m². It will consist of a 12-week intervention followed by a 12 week follow-up period. Researchers will compare a group following the 16:8 time-restricted eating schedule and Low Glycaemic Index Mediterranean Diet to a control group (waiting list) receiving no dietary or meal-timing instructions to determine if these dietary strategies influence cognitive function, assessed via brain-derived neurotropic factor (BDNF) and cognitive function tests, metabolic outcomes, biological age, the gut microbiome, tender and swollen joint count and global health. Participants will: Follow a 16:8 time-restricted eating schedule (eating within an 8-hour window and fasting for 16 hours) if assigned to the intervention group. Adhere to a tailored Low Glycaemic Index Mediterranean Diet and track meals using the Nutrium app. Attend study visits at the University of Nicosia at Week 0, Week 12, and Week 24 for various assessments. Provide biological samples, including blood samples at five specific intervals and stool samples at Week 0 and Week 12. Complete multiple questionnaires regarding diet, lifestyle, sleep quality, physical activity, tender and swollen joints, and quality of life. Undergo physical and cognitive assessments, such as CNS Vital Signs tests, blood pressure measurements, and body composition analysis. The two groups will be compared to understand if the intervention improves outcomes and can thus be applied in this population group.

This randomized controlled trial will run over a period of 24 weeks (6 months) and will be divided into two main phases: a 12-week intervention phase followed by a 12- week follow-up phase designed to assess long-term adherence and health outcomes. The participants will be randomized to one of two groups: the intervention group of a Time-Restricted Eating combined with a Low Glycaemic Index diet (TRE-LGI) group, and the control group which will not receive any dietary intervention. During the intervention phase (Week 0 to Week 12), participants randomized to the TRE-LGI group will follow a structured eating plan. They will be instructed to consume all their meals within an 8-hour eating window each day and adhere to a low glycaemic index Mediterranean-style diet. Participants randomized to the control group will not receive any dietary intervention but will continue to be monitored for study purposes. Assessments will be conducted at three time points during this phase. At baseline (Week 0), participants will complete a full set of evaluations, including the online Computerised Neurocognitive Testing tool CNS Vital Signs, metabolic markers (insulin sensitivity, and lipid profiles, C-reactive protein (CRP), BDNF assessment using Enzyme-Linked Immunosorbent Assay (ELISA) Test, biological ageing assessment using the N-glycome analysis (GlycanAge test), gut microbiome analysis from stool samples, body composition, blood pressure, waist circumference, sleep quality using the Pittsburgh Sleep Quality Index (PSQI), physical activity using the International Physical Activity Questionnaire-Short Form IPAQ-SF, tender and swollen joint count and Global Health using the PROMIS® Scale v1.2 - Global Health. At Week 6, only the N-glycome composition analysis (GlycanAge) will be repeated to monitor changes in biological ageing. At Week 12, all baseline assessments will be repeated to measure the effects of the intervention. The follow-up phase, spanning from week 12-24, will focus on evaluating the participants' ability to sustain the dietary practices achieved during the intervention period without receiving further active dietary guidance. Monitoring will continue to measure the longer-term effects on cognitive, metabolic, and biological health outcomes. At Week 18, participants will undergo N-glycome composition analysis (GlycanAge) to continue monitoring biological ageing. At Week 24, a final comprehensive assessment will be conducted, including cognitive function (CNS Vital Signs), BDNF Test, N-glycome analysis, body composition using BIA, BMI, blood pressure, waist circumference, and sleep quality (PSQI), physical activity (IPAQ-SF), tender and swollen joint count, and Global Health PROMIS questionnaire. Participants in the control group will complete the same assessments at each scheduled time point, allowing for direct comparisons; however, they will not undergo any dietary intervention throughout the study.