Purpose: This systematic review and meta-analysis evaluates the effects of Spirulina supplementation, alone or combined with exercise, on body composition, lipid profiles, glycemic control, blood pressure, and cardiorespiratory health in overweight and obese adults. It also examines the moderating roles of participant characteristics and intervention protocols.Methods: We systematically searched PubMed, Embase, Cochrane Library, and Web of Science from their inception to September 2024. Results were pooled using random-effects models and reported as Hedge’s g (g) with 95% confidence intervals (95% CI). Heterogeneity was explored through subgroup and regression analyses. Bias risk and evidence quality were assessed using the Cochrane RoB 2 tool and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.Results: Twenty-three studies (1,035 participants) were included. Spirulina supplementation alone significantly reduced body weight (g = −0.30, 95% CI: −0.53 to −0.08), total cholesterol (g = −0.79, 95% CI: −1.18 to −0.41), triglycerides (g = −0.64, 95% CI: −1.00 to −0.28), low-density lipoprotein cholesterol (LDL-C; g = −0.71, 95% CI: −1.13 to −0.29), and diastolic blood pressure (g = −0.73, 95% CI: −1.43 to −0.03), while increasing high-density lipoprotein cholesterol (HDL-C; g = 0.53, 95% CI: 0.04 to 1.02). When combined with exercise, Spirulina further improved HDL-C (g = 1.08, 95% CI: 0.37 to 1.79) and LDL-C (g = −0.81, 95% CI: −1.59 to −0.04). Subgroup and regression analyses revealed that participant age, body mass index, health status, Spirulina form, dosage, and intervention duration influenced outcomes.Conclusion: Spirulina may serve as a valuable adjunctive therapy for overweight and obese individuals with metabolic disorders, reducing cardiovascular risk by improving lipid profiles, blood pressure, and body weight. Combining Spirulina with exercise enhances certain lipid outcomes. However, its overall impact on body composition and glycemic control appears limited. Further research is needed to confirm its long-term efficacy.Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD42024573534, identifier CRD42024573534.

Non-alcoholic fatty liver disease (NAFLD), the most prevalent chronic liver illness, is characterized by hepatic steatosis. Exercise and probiotics can regulate the gut microbiota to treat NAFLD; however, their combined effects and the mechanisms of gut-liver communication remain unclear. Inconsistent results on probiotic efficacy further warrant investigation. In this study, zebrafish fed a high-fat diet (HFD) for six weeks were subjected to swimming exercise (HFDE), probiotic intervention (HFDP), or a combination of both (HFDEP) for 10 weeks to explore their effects on NAFLD and the corresponding mechanism. The results showed that NAFLD alleviation followed the order HFDEP > HFDE > HFDP. HFDEP and HFDE treatments effectively reduced Body Mass Index (BMI), relative liver weight, liver vacuolation density, lipid droplets in liver sections, triglyceride, free fatty acid, glucose, and pyruvic acid. In contrast, a single probiotic treatment had limited impact, suggesting a complementary role in NAFLD treatment. Glucose and fatty acid metabolism were central to the “gut–liver” axis. The reduced conversion of glucose to pyruvic acid, decreased fatty acid synthesis and esterification, and accelerated fatty acid transformation to CO₂ contributed to NAFLD improvement under HFDE and HFDEP treatments. This study provides promising theoretical groundwork for potential prevention and treatment strategies for NAFLD.