The increasing interest in scientifically proven health products has accelerated the search for bioactive compounds that have known therapeutic actions, and which can be produced with stability. Postbiotics, such as short-chain fatty acids (SCFAs), organic acids, proteins, vitamins, bacteriocins, and tryptophan (Trp), are recognized as advantageous bioactive compounds produced by commensal microbiota in the gut during fermentation, which can enhance consumer health. Recently, a number of functional effects ensued, such as immunomodulatory effects, anti-inflammatory effects and metabolic regulating effects caused by conserved microbial components and bioactive metabolites. While many interesting findings have emerged, a number of challenges are evident in bringing them to clinical and industry based applications. The lack of standardisation in terms of production and characterisation techniques has led to differences in bioactivity from study to study. In vitro and animal studies have shown a number of pleiotropic effects, from anti-microbial to anti-hypertensive, whereas to date there are few randomised clinical trials presented, with the mechanistic basis not clearly established, and inferred. Major gaps in knowledge still exist with regard to dose-response apparats, long term safety and effecacy in certain populations. This review will consolidate the current understanding of postbiotic production methods, mechanisms of action and health benefits shown, while the barriers to use in functional foods will be critically reviewed. Overcoming these barriers by means of clinical studies employing randomised trials, standardised protocols and mechanistic studies will offer a chance to benefit from the complete realised potential of postbiotics as next generation therapeutics.
Bodjrenou et al. (Sun,) studied this question.