Abstract
Introduction: In the context of chronic noncommunicable diseases, obesity represents a pandemic represented as a long-term chronic imbalance between calorie intake and energy expenditure, resulting in more than 2.0 billion overweight and obese people worldwide. Objective: It was to present the major considerations and results of clinical studies on the relationship between nutrients, gut microbiota, and microRNAs for healthy weight loss through a systematic review. Methods: The PRISMA Platform systematic review rules were followed. The search was carried out from August to September 2024 in the Web of Science, Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 142 articles were found, and 35 articles were evaluated in full and 28 were included and developed in the present systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 25 studies with a high risk of bias and 22 studies that did not meet GRADE and AMSTAR-2. Most studies showed homogeneity in their results, with X2=72.4%>50%. It was concluded that diet is a determining factor for a healthy colonization of the gut microbiota. Adipose tissue hypertrophy causes metabolic and hemodynamic disorders through the production of several adipokines that play a role in the genesis of insulin resistance and atherosclerosis. Studies in humans with obesity have also found a lower proportion of Bacteroidetes compared to eutrophic individuals. Furthermore, when they lose weight, the proportion of Firmicutes decreases and becomes more similar to that of lean individuals. Maintaining a healthy metabolism depends on a symbiotic consortium between bacteria and other intestinal microorganisms. Furthermore, microRNAs regulate gene expression in adipose tissue, impact the regulation of metabolism and energy homeostasis, and regulate adipogenesis signaling pathways in white, beige, and brown adipose tissue. For example, microRNA (miR-143) promotes thermogenesis in brown adipose tissue and inhibits adipogenesis in white adipose tissue. Some miRNAs have been implicated in the control of body weight gain, glucose homeostasis, insulin resistance, and lipid metabolism, with crosstalk with the gut microbiota. Furthermore, an association was found between B. eggerthi abundance, miR-183-5p expression, and adiponectin levels. miR-15a-5p expression was found to be associated with H. parainfluenza abundance and insulin levels.