Chlorella supplementation diminishes cardiovascular risk factors in adults: A GRADE-assessed systematic review and meta-analyses of randomized clinical trials

Background

Cardiovascular disease (CVD) poses significant health challenges and life-threatening risks worldwide. Reducing risk factors for CVD has led to a decrease in its prevalence. Chlorella, a green alga, has beneficial cardiometabolic effects.

Methods

Systematic searches were performed in Web of Science, Scopus, and PubMed/Medline through January 10, 2025, to identify relevant randomized controlled trials (RCTs) according to the PRISMA checklist and PICOS criteria (Population: adults >18 years, Intervention: chlorella, Comparison: placebo/control, Outcomes: BMI, weight, hs-CRP, FBG, HOMA-IR, insulin, TG, TC, HDLC, LDL-C, SBP, DBP, and Study: RCTs). A meta-analysis was conducted using random-effects models. The GRADE framework was used to assess evidence certainty.

Results

In the 25 studies (33 effect sizes), chlorella supplementation improved dyslipidemia (TC: WMD = −5.26 mg/dl, P < 0.001; LDL-C: WMD = −7 mg/dl, P < 0.001; HDLC: WMD = 2.34 mg/dl, P = 0.006), enhanced insulin sensitivity (HOMA-IR: WMD = −0.31, P = 0.004), lowered blood pressure (SBP: WMD = −3.68 mmHg, P = 0.005; DBP: WMD = −2.04 mmHg, P = 0.04), diminished anthropometric measures (weight: WMD = −1.37 kg, P = 0.001; BMI: WMD = −0.25 kg/m², P < 0.001), and reduced inflammation (hs-CRP: WMD = −0.74 mg/dl, P < 0.001). Chlorella supplementation did not affect TG, FBG, and insulin levels. GRADE analysis showed low-quality evidence for hs-CRP and FBG, high-quality evidence for TC, LDL-C, and BMI, and moderate-quality evidence for other parameters.

Conclusions

This systematic review and meta-analysis demonstrate that chlorella supplementation improves blood pressure, anthropometric measures, insulin sensitivity, inflammatory markers, and dyslipidemia, which may help lower CVD risk in adults. However, more studies are needed to confirm these facts.