To overcome the potential safety issues associated with viable probiotics, the alternative represented by bacterial strains inactivated by a thermal process is being investigated. A recent review analyzed data from recent studies on these forms
Today, the importance of the gut microbiota to human health is recognized, and knowledge about the composition and functions of the bacterial populations in the gut and the influence of dysbiosis in the development of various disorders and diseases has been deepened.
With the acquisition of this knowledge, interest in the therapeutic strategies aimed at regulating the microbiota, including the administration of probiotics, which have shown very significant potential against numerous intestinal and extra intestinal diseases: infectious and antibiotic-associated diarrhea, ulcerative colitis, irritable bowel syndrome, functional gastrointestinal disorders, necrotizing enterocolitis, and hepatic encephalopathy.
Alongside the positive results in terms of efficacy, however, some controversial issues have been highlighted regarding the safety profile of viable probiotic microorganisms, particularly in vulnerable people and child populations. The risk is related to the eventual translocation of bacteria from the gut to the bloodstream, with the possibility of systemic infection, and the development of antibiotic resistance, as well as interference with gut colonization in infants.
For this reason there has recently been growing interest in the use for probiotic purposes of nonviable microorganisms or microbial cell extracts, mainly probiotic bacteria inactivated by heat treatment.
In fact, contrary to what one might think, bacterial viability is not an essential condition for a probiotic to exert a beneficial effect in the gut.
A group of Spanish researchers conducted a review of data from recently published studies to take stock of the potential benefits of tindalized probiotics in the treatment of intestinal disorders and their safety profile compared with that of viable strains.
The benefits of tindallyzed probiotics
There are several bacterial strains that can exert beneficial effects in the tindalized form: these include lactic acid bacteria and bifidobacteria.
In addition, some research results have also provided evidence of biological effects for metabolites, cell fractions and culture supernatants of probiotic bacteria.
Regarding the biological effects associated with these inactivated forms, studies have provided indications supporting an immunomodulating action, a protective effect against intestinal pathogenic microorganisms, and an activity to maintain the integrity of the intestinal barrier.
From the point of view of clinical effects, in the studies analyzed, tindalized probiotic strains have been shown to play a positive role in the management of various gastrointestinal disorders, such as bloating and diarrhea and infantile colitis through their use in combination with mucosal protective drugs. Outside the gastrointestinal setting, moreover, probiotics in a heat-inactivated form could be useful in the management of allergic dermatological or respiratory diseases.
Strategies with good prospects
“Overall, data from the studies included in the review indicate that alternatives to viable probiotics, including tindalized forms, cellular fractions and purified components, have important beneficial effects,” the authors of the paper comment. “Compared with viable probiotics, these forms offer advantages primarily in terms of safety profile and represent promising strategies for the management of several common disorders in patients with different characteristics, particularly in vulnerable individuals such as infants.”
Reference
Piqué N, Berlanga M, Miñana-Galbis D. Health benefits of heat-killed (tyndallized) probiotics: An overview. Int J Mol Sci. 2019 May 23;20(10):2534.
