Twenty years review of probiotic meta-analyses articles: Effects on disease prevention and treatment

The study of the probiotic effect in the prevention or treatment of diseases has long attracted the attention of many researchers. Here, we collected close to 300 meta-analysis articles for 20 years, investigating the effect of probiotics in the prevention and treatment of diseases. The goal of this study is to provide an overview of all meta-analysis articles of the effects of probiotics on various human diseases. For this purpose, different online databases, Pubmed, ScienceDirect, and Google Scholar, were searched with the keywords "probiotics" + "disease" + "meta-analysis" in the title, abstract, and keywords. Papers studied and categorized and investigated in order to present valuable insights for researchers in the field. Some of main categories are based on publication year, publishing journals, gender, age, effect type, disease type, contradicting reports and etc. According to the results, most meta-analyses indicated probiotics were 79% effective in preventing or treating the diseases. Some articles have also reported no positive effects, but there is not any paper in our study confirming the detrimental influence of probiotic effect on human health. For the future works, Cochrane reviews, meta-analysis including dozens of articles (as e.g. for NEC and AAD) may be investigated.