A notable shift in understanding the human microbiome’s influence on cardiovascular disease (CVD) is underway, although the causal association remains elusive. A systematic review and meta-analysis were conducted to synthesise current knowledge on microbial taxonomy and metabolite variations between healthy controls (HCs) and those with CVD. An extensive search encompassing three databases identified 67 relevant studies (2012–2023) covering CVD pathologies from 4707 reports. Metagenomic and metabolomic data, both qualitative and quantitative, were obtained. Analysis revealed substantial variability in microbial alpha and beta diversities. Moreover, specific changes in bacterial populations were shown, including increased Streptococcus and Proteobacteria and decreased Faecalibacterium in patients with CVD compared with HC. Additionally, elevated trimethylamine N-oxide levels were reported in CVD cases. Biochemical parameter analysis indicated increased fasting glucose and triglycerides and decreased total cholesterol and low- and high-density lipoprotein cholesterol levels in diseased individuals. This study revealed a significant relationship between certain bacterial species and CVD. Additionally, it has become clear that there are substantial inconsistencies in the methodologies employed and the reporting standards adhered to in various studies. Undoubtedly, standardising research methodologies and developing extensive guidelines for microbiome studies are crucial for advancing the field.

Background/Objectives: Chlorella and Spirulina supplementation may reduce the risk of cardiometabolic diseases by better controlling blood cholesterol, triglycerides, glucose, weight, and blood pressure (BP). However, the available studies are limited in size and have used different outcomes. Methods: To gain power in assessing the impact of microalgae supplements on cardiovascular risk factors, we searched PubMed on 3 February 2023 for randomised controlled trials assessing the effects of Chlorella and Spirulina on modifiable cardiovascular risk factors. Results: We found 12 studies in Chlorella and 9 studies on Spirulina. Depending on the available outcomes, varying numbers of participants (Chlorella: 168 to 279; Spirulina: 101 to 299) were included. Our analysis showed that Chlorella supplementation had a neutral effect on BP and lipemia. On the other hand, Spirulina intake led to a significant reduction in diastolic BP (−0.42, 95% CI: −0.81 to −0.02, p = 0.04) but did not significantly affect lipemia indexes, despite a trend toward a reduction in total cholesterol (−0.17, 95% CI: −0.39 to 0.06, p = 0.15). This meta-analysis suggests Spirulina supplementation can be used as an adjuvant to control cardiometabolic risk factors, particularly for BP. However, the magnitude of this effect is small and of uncertain clinical significance. Conclusions: Further randomised trials are needed to better assess the potential of these supplements as adjuvants for the control of cardiovascular risk factors.