Effect of Moringa oleifera on haematological parameters: a systematic review

Background: Moringa (Moringa oleifera) is a plant found in many regions. Its extracts, especially of leaves, are a rich source of fibre, proteins and micronutrients including iron, thus potentially be used for haematological-applications including iron-deficiency-anaemia, affecting approximately one-third of the global population. Aims: To systematically-review the effect of moringa on haematological-parameters. Methods: Preferred-Reporting-Items-for-Systematic-Reviews (PRISMA) guidelines were followed. PubMed, Cochrane-library, Agricola, CINAHL and EMBASE databases were searched. Selection of articles were done in three rounds by two independent reviewers intervened by a third, resolving conflicts. Human-studies on Moringa with relevant outcomes were included. Risk-of-bias assessment was done with Grading-of-Recommendations-Assessment-Development-and-Evaluation (GRADE) criteria. Heterogeneity was assessed and results were narratively-synthesized without meta-analysis. Registration from International-Prospective-Register-of-Systematic-Reviews (ID: CRD42020181432) was obtained. Results: Following de-duplication there were 213 articles. Six studies on Moringa-leaf extracts, covering nine outcomes were included. Four studies included children below 2 years and two included reproductive and post-menopausal women. Among children under 2 years, mean improvement in heamoglobin-level ranged between 0.31-2.6g/dl with a reduction of the prevalence of anaemia by 53% (95%CI:35.1-72.0;p