Metabolic syndrome (MetS) and obstructive sleep apnea (OSA) are prevalent and interrelated conditions in older adults, both contributing to decreased quality of life and increased health risks. Nutritional interventions, including dietary changes and probiotic supplementation, may offer effective non-pharmacological strategies to address these conditions. This study aimed to evaluate the impact of diet therapy alone and in combination with probiotics on quality of life and sleep apnea risk in older adults (>60 years) with MetS. In this controlled interventional study, 192 older adults with metabolic syndrome were assigned to one of three groups: control, diet therapy alone, or diet therapy plus probiotic supplementation. Participants were evaluated at baseline and after the intervention period using the SF-36 quality of life questionnaire and an apnea risk screening tool. Clinical and metabolic parameters, including BMI, HOMA index, and visceral fat, were also assessed. Significant improvements in SF-36 scores were observed in both intervention groups compared to the control group ( < 0.05) (mean difference = -5.31, = 0.016), with the diet + probiotics group showing the greatest enhancement. Participants who reduced their apnea risk also reported higher post-intervention SF-36 scores. The intervention led to reductions in visceral fat, inflammatory markers (CRP), and insulin resistance (HOMA index), which were correlated with improved quality of life. Integrated nutritional strategies, especially the combination of diet and probiotics, significantly improve quality of life and reduce apnea risk in older adults with metabolic syndrome. These findings support the use of personalized, non-pharmacological interventions targeting both metabolic health and sleep-related outcomes in geriatric populations.