The paper was the work of researchers associated with Rutgers State University and institutions in South Korea, Bulgaria and Russia. It was published in the journal Critical Reviews in Microbiology.
The paper notes that evidence of the existence of Bacillus microorganisms, which form spores found in soils, extends back for millions of years. Traces of these microorganisms have been found in amber deposits, and viable spores have been discovered in polar permafrost.
The researchers noted that such microorganisms have probably been a standard feature of the human gastrointestinal tract from the beginning of the species. Bacillus spores enter the body on vegetables and other foods harvested close to the ground or picked up after falling from trees. As such, the organisms have probably been extant in most human guts for millennia.
Present, yes. But beneficial?
The question the paper’s authors sought to address was whether this class of organisms could be considered truly beneficial. Presence in the gut isn’t the only measure of this. After all, people living in dusty environments inevitably have dust particles in their lung tissue. Are these providing a health benefit? Or is it merely an environmental stressor that those people’s bodies have to adapt to?
Members of the Bacillus species form hardy spores that can persist in soils and on surfaces for years, waiting to be deposited in a suitable environment for germination. Some of those permafrost spores were able to germinate after as much as 10,000 years on ice.
These hardiness of these organisms can make them difficult to eradicate when processing foods. They can also give rise to hardy metabolites, too, some of which can cause problems. The paper states that strains of B. subtilis, B. amyloliquefaeiens, and B. mojavensis and other strains of species in the genus have been reported to produce heat stable toxins related to food poisoning.
The difficulty of eradicating both spores themselves and some of their metabolites in cases where these are potentially harmful had let some industry observers to question whether these organisms were the best choice for probiotic ingredients. On the other hand, the durability of the spores has made them attractive for formulation purposes.
The history of these ingredients in the marketplace has shown little cause for concern. What issues do exist are common among many categories of dietary supplements, namely, that the best manufacturers do things right, while others occupy lower rungs of the quality ladder.
“Many commercial products containing B. subtilis spores are mislabelled and contain other bacilli, including B. clausii, B. pumilus, and a variety of B. cereus strains,” the authors note.
Getting (strain) specific
The authors then get to the crux of the matter.
“It is a well-known fact that different strains from the same species can be considered and identified as probiotics; however, this must not be granted to the entire genus nor the species but must remain affirmed only to a specific strain and only after appropriate in vitro testing and in vivo trials,” they wrote.
Sabinsa, an Indian supplier of botanicals, a Bacillus probiotic and fine chemicals, had this to say about that statement:
“Sabinsa is in total and complete agreement with this statement. That is why Sabinsa conducted numerous studies and clinical trials, collaborating often with academic groups, to establish safety foremost and efficacy as proven benefits of its proprietary and trademarked Bacillus coagulans strain, Lactospore MTCC 5856. (The paper incorrectly refers it as B clausii in Table 1).
"In fact Sabinsa’s safety data on Lactospore MTCC 5856 strain of B coagulans has been reviewed by the US FDA, leading it to its GRAS status. In addition, Sabinsa’s specifications for Lactospore are stringent, guaranteeing its quality and safe use. The paper cautions against consumption of probiotics without safety and clinical evidence of their benefits.”
John Quilter, vice president of Kerry's Global Portfolio - ProActive Health division, noted that Kerry, and Ganeden prior to its acquisition, has done more than 30 studies on its branded BC-30 strain of Bacillus coagulans.
"This is analogous to discussions that have occurred with respect to vegetative probiotics (some years ago), it is part of a healthy debate on the science and benefits of probiotics. This research highlights the importance of strain-specific research and that research from one strain cannot be attributed to another. That’s why Kerry continues to focus our efforts on developing the science for our leading spore-forming probiotics at the strain level, and continue to ensure that we can validate the safety, efficacy, and viability of our BC30 probiotic (Bacillus coagulans GBI-30 6086) across a wide range of applications and need states," he said.
Generalization about 'sport formers' doesn't make sense
Probiotics consultant Mary Ellen Sanders, PhD, said she agreed, too, with the paper’s basic tenets.
“It’s not possible to generalize about the safety or efficacy of ‘spore formers’. They may be pathogenic, toxigenic or have other safety issues, or they may not. Any spore former recruited to be a candidate probiotic must meet safety and efficacy requirements for the specific strain. Less than that, it is not a probiotic,” she said.
And as Prof Colin Hill, PhD, of University College Cork in Ireland put it in a recent commentary:
“I have long held the view that we should not rigidly adhere to the concepts of pathogens, commensals and probiotics when describing microorganisms. Many, if not all, of the microorganisms that we ordinarily define as probiotics or as gut commensals would cause problems if present in the blood, brain or other sites of the body that are typically sterile.”
Source: Critical Reviews in Microbiology
doi.org/10.1080/1040841X.2021.1983517
Bacillus spore-forming probiotics: benefits with concerns?
Authors: Todorov SD, et al.