Quality of life (HRQoL) plays a pivotal role in predicting health outcomes, particularly in individuals susceptible to metabolic disorders. Recent research highlights the correlation between low HRQoL and heightened cardiometabolic risks, underscoring the significance of interventions aimed at enhancing subjective well-being.
The 36-item short-form health survey (SF-36) serves as a standard tool for assessing HRQoL, while sleep quality is increasingly recognized as a critical determinant of cardiometabolic health and HRQoL.
Studies have previously indicated that adherence to Mediterranean-style dietary patterns (MED-HEPs) correlates with improved well-being and HRQoL. However, most of these studies have been observational, necessitating more rigorous intervention trials.
The glycemic index (GI) of food reflects its impact on blood glucose levels, with lower GI foods generally producing smaller glucose fluctuations. Despite its relevance, no prior intervention study has explored the effects of GI on HRQoL in individuals at elevated cardiometabolic risk.
Study Overview:
Researchers conducted a multicenter, randomized controlled trial known as MedGICarb between January 2018 and March 2020 across sites in Sweden, Italy, and the United States. The study targeted older and middle-aged adults exhibiting multiple features of metabolic syndrome, such as abdominal obesity and elevated blood pressure or glucose levels.
Participants were excluded if they had recent cardiovascular events, diabetes, or other conditions that might interfere with study outcomes. During the intervention phase, which followed a three-week baseline period, participants adhered to either a low- or high-GI MED-HEP while maintaining their usual physical activity levels.
Intervention Details:
Both groups consumed a MED-HEP designed to maintain weight, with the only difference being the glycemic index of the carbohydrate sources used. The study ensured identical fiber and carbohydrate content across diets, with variations limited to half of the carbohydrate intake.
Outcome Measures:
HRQoL was assessed using SF-36, while sleep quality was evaluated via the Pittsburgh Sleep Quality Index (PSQI) and daytime sleepiness using the Epworth Sleepiness Scale (ESS). Questionnaires were administered at baseline and during the final two weeks of the 12-week intervention period.
Key Findings:
Of the initial participants, 73 in the low-GI group and 87 in the high-GI group completed the study. Analysis indicated modest enhancements in HRQoL domains related to physical function and vitality among those on the low-GI MED-HEP compared to the high-GI group. However, no significant differences in sleep quality were observed between the two groups.
Participants in both groups reported improvements in overall health and vitality during the intervention period. Notably, while sleep latency and daytime dysfunction improved in both groups, these changes did not differ significantly between the low- and high-GI MED-HEP groups.
Conclusion:
The study concludes that adopting a low-GI MED-HEP can lead to modest improvements in specific aspects of HRQoL, particularly related to physical function and vitality, in adults at risk of metabolic disorders. However, the findings did not reveal any distinct benefits regarding sleep quality. The study’s generalizability may be limited by its primarily Caucasian participant base.
In summary, consuming low-GI foods as part of a Mediterranean-style diet may offer additional health benefits, emphasizing the importance of dietary interventions in promoting self-perceived health among at-risk populations.