Time Restricted Feeding as a Tool to Modulate the Gut Microbiome
The gut microbiome changes with age, the balance of microbial populations shifting to cause more inflammation and a lesser production of beneficial metabolites. To what degree can forms of fasting and time restricted feeding improve the aged gut microbiome? The authors of this paper seem optimistic, but more data is needed. Particularly, I'd want to see data in calorie restricted or intermittently fasted old rodents in direct comparison with the effects of fecal microbiota transplant from young animals. Obtaining human data for the same interventions should not be too challenging a prospect; it just requires the will and funding to run a small and informal clinical trial.
The manipulation of the gut microbiota composition through dietary changes and intermittent fasting (IF) has emerged as a potentially effective "pharmaco-nutritional" strategy for reversing dysbiosis and host metabolic disorders. However, the conventional medical care system does not yet have the capability of evaluating both the qualitative and quantitative changes that occur in the gut microbiota. At the population level, one potential strategy for the prevention and management of metabolic syndrome should involve the development of a set of approaches related to changes in the microbiota of the gut. TRF stands for time-restricted feeding in animals and time-restricted eating (TRE) in humans throughout a counted number of hours. It allows for a daily fasting duration that is greater than 12 hours, and it does so without affecting either the quality or quantity of the nutrients consumed. Through the involvement of circadian genes and the gut microbiome, time-restricted feeding/eating (TRF/E) provides protection against nutritional challenges that can lead to obesity and metabolic risks. It has been hypothesized that TRF/E may regulate and modulate gut microbiota in order to prevent metabolic disease through multiple pathways.
It is still too soon to determine how TRF/E affects the composition of the gut and the functions it performs through daily feeding and fasting rhythms. Previously, TRF imposed significant alteration in the microbial composition of human gut microbiota. There were substantial alterations and relative richness of bacterial communities in healthy persons using combined effect size measures from linear discriminant analysis (LDA). These communities were classified as either TRF or non-TRF. At the level of the genus, 34 bacteria were enriched in the TRF group, and 18 bacteria were enriched in the non-TRF group. The most numerous genera in the TRF group were Bacteroidetes and Prevotellaceae (prevotella 9 and prevotella 2), while the most numerous genera in the non-TRF group were Escherichia, Shigella, and Peptostreptococcus. Similarly, a study revealed that timed-feeding protocols (TRF, alternate day fasting and caloric restriction) induced measurable shifts in the bacterial compositions in mice that coincide with improvements in metabolism. TRF, on the other hand, was successful in reestablishing cyclical variation in several bacterial families that are thought to play a role in metabolism.