Probiotics: A new target for metabolic disease regulation

Metabolic syndrome is a construct relating to a series of metabolic dysfunctions attributable to insulin resistance and obesity. In recent years, the incidence of metabolic diseases has gradually increased, which seriously affecting the quality of life of individuals, and has become a worldwide public health problem. The prevalence of metabolic disorders is associated with dynamic changes in dietary macronutrient intake and lifestyle changes during the past decades. Recently, the scientific community has considered alteration in gut microbiota composition to constitute one of the most probable factors in the development of metabolic disorders. How to improve metabolic syndrome by regulating the gut microbiota has become a research hotspot. Probiotics, as a living microorganism beneficial to human health, has been widely applied in different foods, which can improve blood glucose, regulate blood lipid and reduce insulin resistance and cholesterol by regulating gut microbiota. Animal experiments and clinical trials demonstrated that probiotics, especially Lactobacillus and Bifidobacterium, had a good effect on the improvement of metabolic syndrome, showing the features of weight loss, lowering blood lipid, blood pressure and blood sugar and so on. Studies have shown that probiotics play a regulatory role in metabolic syndrome. Firstly, the data showed that the fat synthesis had been inhibited and its dissolves had been enhanced by probiotics. Secondly, probiotics protected pancreatic islet cells, improved insulin sensitivity and accelerated glucose transport. Finally, probiotics also increased the converse of cholesterol and the excretion of bile acid, and released angiotensin converting enzyme inhibitory peptides. However, some people hold neutral or opposing views. The paper reviewed the specific effects and mechanisms of probiotics in metabolic diseases such as obesity, type 2 diabetes mellitus (T2DM) and hypertension, and the problems which will be faced in application, so as to provide new ideas for the industrial development and application of probiotics in the future. Although probiotics have shown excellent performances in regulating metabolic diseases, there is still a long way to achieve their clinical applications. Some of the proposed experimental evidence and mechanisms specifically targeting metabolic diseases effects remain inconclusive, and differences in probiotic strains, dosages and duration of effects remain to be explored. Therefore, more specific and thorough in vivo and clinical trials will need to be designed in the future to improve our understanding and eliminate uncertainty. Meanwhile, there are currently no standard safety guidelines for oral probiotics and prebiotics for use in human. Therefore, each probiotics and prebiotics should be carefully evaluated to identify potential adverse reactions. Future research is needed to increase our understanding of the complex interactions between gut and ingesting microbes. Nevertheless, we still believe that probiotics are expected to play an important role in metabolic diseases in the near future.