Reference
Clemente F, Bravini E, Corna S, Colombo E, Sartorio F, Rinaldi C, Vercelli S. The relationship between physical exercise and gut microbiota in the human being:a systematic review. Epidemiol Prev 2021; 45 (4):245-253. doi: 10.19191/EP21.4.P245.080
At a glance
Results of a recent review focused on some aspects of the effects of physical activity on the composition of gut microbiota and the relationship between the level of cardiorespiratory fitness
(CRF) and gut microbiota.
The context
Recent literature has highlighted how being physically active can influence gut microbiota and promote a systemic anti-inflammatory state. These findings have opened the debate for new therapeutic frontiers for many inflammatory diseases. Regular physical activity, including by means of exercise, is therefore very important. That said, there is still a lot of uncertainty about how to administer exercise. Moreover, there are many cofactors that influence gut microbiota, such as diet
and medications.
Characteristics of the study
The study by Clemente and colleagues aims at reviewing the existing literature regarding physical activity and its effects on gut microbiota, filling in the aforementioned gaps, and analyzing the
relationship between CRF and gut microbiota. The systematic review includes studies involving humans undergoing exercise programs of any length, intensity and type. The research was carried out on the PubMed, Scopus, and Web of Science databases.
Results
The 15 studies included used aerobic training, alone or combined with resistance exercises. In general, exercise had positive effects on the microbiota, influencing the fecal count of some phyla bacterial (in particular Bacteroidetes, Firmicutes, and Proteobacteria), which have a weak interaction with training duration and intensity. That said, a correlation between CRF and gut microbiota has not yet been found.
Limits of the study
The clinical trials included in the study were of low quality and methodological rigor according to the Physiotherapy Evidence Database scale and Cochrane Collaboration Risk of Bias tool. Currently, there is a lack of studies investigating the effects of isolated resistance training on the composition of intestinal microbiota. Moreover, the heterogeneity in the reporting of taxonomic units made it impossible to identify the bacterial taxa associated with an improved microbial profile.
What is new?
There is moderate evidence that aerobic exercise, on its own or combined with resistance exercises, may positively influence the composition of gut microbiota. However, the study of the effects of physical exercise on gut microbiota composition is only exploratory, and many aspects of this subject require further analysis.
Perspectives
The shortcomings that emerged from this systematic review could be helpful for future studies. Such studies are needed to investigate the effects of isolated resistance training on gut microbiota. Higher quality and methodological rigor are required to standardize outcome assessment and to identify the type, intensity and duration of the interventions. Finally, Firmicutes, Bacteroidetes and Proteobacteria could become a minimum core set, in order to standardize the reporting of taxonomic units in future studies.
A cura di Elisabetta Bravini e Carmela Rinaldi
