Quantifying the effects of spirulina supplementation on plasma lipid and glucose concentrations, body weight, and blood pressure

Purpose: Spirulina is generally used as a nutraceutical food supplement due to its nutrient profile, lack of toxicity, and therapeutic effects. Clinical trials have investigated the influence of spirulina on metabolic-related risk factors but have yielded conflicting results in humans. Here, we summarize the evidence of the effects of spirulina on serum lipid profile, glucose management, BP, and body weight by conducting a meta-analysis. Materials and methods: Relevant studies were retrieved by systematic search of MEDLNE, EMBASE, Scopus databases, and reference lists of relevant original studies from inception to July 2018. Data were extracted following a standardized protocol. Two investigators independently extracted study characteristics, outcomes measures, and appraised methodological quality. Effect sizes were performed using a random-effects model, with weighted mean differences (WMDs) and 95% CIs between the means for the spirulina intervention and control arms. Subgroup analyses were conducted to explore the possible influences of study characteristics. Publication bias and sensitivity analysis were also performed. Results: A total of 1,868 records were identified of which 12 trials with 14 arms were eligible. The amount of spirulina ranged from 1 to 19 g/d, and intervention durations ranged from 2 to 48 weeks. Overall, data synthesis showed that spirulina supplements significantly lowered total cholesterol (WM D = 36.60 mg/dL; 95% CI: -51.87 to 21.33; P=0.0001), low-density lipoprotein cholesterol (WMD = -33.16 mg/dL; 95% CI: -50.52 to -15.75; P=0.0002), triglycerides (WM D = 39.20 mg/dL; 95% CI: -52.71 to 25.69; P=0.0001), very-low-density lipoprotein cholesterol (WMD = -8.02 mg/dL; 95% CI: -8.77 to -7.26; P=0.0001), fasting blood glucose (WMD = -5.01 mg/dL; 95% CI: -9.78 to -0.24; P=0.04), and DBP (WMD = -7.17 mmHg; 95% CI: -8.57 to -5.78; P=0.001). These findings remained stable in the sensitivity analysis, and no obvious publication bias was detected. Conclusion: Our findings provide substantial evidence that spirulina supplementation has favorable effect on select cardiovascular and metabolic biomarkers in humans, including lipid, glucose, and DBP management.