What are spore-based probiotics?
Spore-based probiotics are produced by bacteria found mainly in soil. They contain endospores, which encase the probiotic strain, making it tolerant of heat, light, and harsh conditions. Traditionally, they have been consumed in freshly-harvested produce, spring and well water, and in fermented foods. However, very little of these bacteria are left in the processed foods we consume today.
Many of them fall under the genus Bacillus and have higher tolerance for stomach acid and bile salts, making them a great choice when facing gastrointestinal tract issues. The endospores, the bacteria’s survival strategy, are some of the most durable types of cells found in nature. Bacillus endospores have been isolated from amber more than 25 million years old, showing their resilience and protective capability. Some parts of the GI tract represent a toxic environment for aerobic probiotic bacteria, such as the beneficial Bacillus species, due to the absence of oxygen, low pH, bile salts, and high concentration of commensal bacteria competing for nutrients. The spores remain inert to these conditions and facilitate the transit of the spore-based probiotics through the GI tract in order to reach the intestines.
Even though they are usually considered soil microorganisms, some spore-based probiotics, such as Bacillus subtilis, have been found in stool and ileal biopsies of volunteers. This suggests that they may have adapted to life within the human GI tract, including their ability to generate biofilm, form spores anaerobically, and produce antimicrobials.
A randomized, double-blind, controlled trial (n = 11) demonstrated that a specific spore-based probiotic strain, Bacillus subtilis DE111®, can successfully germinate in the small intestine, after surviving the harsh gastric conditions of the stomach and the bile salts in the duodenum. Three hours after supplementation, B. subtilis spores and vegetative cells began to appear in the ileum. Six to eight hours after ingestion, the spore concentrations increased to 9.7 × 107 ± 8.1 × 107 colony-forming units per gram (CFU/g). Vegetative cells reached a concentration of 7.3 × 107 ± 1.4 × 108 CFU/g at seven hours following ingestion. These results suggest that B. subtilis DE111® spores are able to remain viable during transit through the stomach and germinate in the human small intestine within three hours of oral supplementation.
Several studies have examined how spore-based probiotics work. A review summarizing the probiotic effects of the Bacillus spp. proposed that the mechanisms by which they may enhance the health of their host include supporting the immune system, modulating the composition of the GI microbiome, and promoting the synthesis of enzymes, vitamins, and various antimicrobials. For example, Bacillus spp. have been shown to produce several antimicrobial substances, such as the bacteriocins subtilin and coagulin and the antibiotics surfactin and bacilysin.
The modulatory effect that spore-based probiotics may have on the gut microbiome involves promoting other beneficial microbes and mitigating pathogens and the associated inflammatory responses. Bacillus subtilis, in particular, has been shown to constrain the growth of Candida albicans in the GI tract, which is attributable to the production of surfactin. A randomized controlled human trial (n = 6) examined the effect of Bacillus clausii on gene expression and concluded that it modulates the genes involved in inflammation, immune response, intestinal permeability, cell growth, differentiation, signaling, and apoptosis in the intestinal mucosa.
How do spore-based probiotics support gut health?
Spore-based probiotics play an important role in the GI microbiome and have been associated with multiple gut health benefits, including supporting the bacteria producing short-chain fatty acids (SCFAs), mitigating lipopolysaccharides-induced endotoxemia and gut permeability, improving quality of life in patients with irritable bowel syndrome, reducing the duration and hospitalizations of patients with childhood diarrhea, and maintaining overall antioxidant status and immune health. Bacillus spp. may also have the capacity to produce enzymes, such as amylase, glucoamylase, protease, pectinase, and cellulase. Bacillus clausii, Bacillus coagulans, and Bacillus subtilis have been shown to support a healthy gut microbiome, vitamin synthesis, intestinal barrier integrity, and overall digestive and immune health in adults and children.
Some medications, such as glucagon-like peptide-1 receptor agonists (GLP-1 RAs) may be associated with GI disturbances, including nausea, vomiting, diarrhea, and constipation. Spore-based probiotics can help reduce GI complaints by supporting microbiome balance, intestinal barrier integrity, and a healthy inflammatory response. For example, Bacillus subtilis has been shown to promote bowel regularity and function and overall GI health.
There are multiple studies supporting the role of spore-based probiotics in gut health. A meta-analysis of randomized controlled trials found that Bacillus clausii may help reduce the duration and frequency of acute diarrhea. A clinical study (n = 5) found that Bacillus coagulans can modulate the GI microbiome and improve its biodiversity in individuals with IBS. Another clinical study (n = 15) reported that Bacillus coagulans may exhibit antimicrobial properties and suppress bacteria from the family Enterobacteriaceae in patients with ulcerative colitis and enhance the intestinal microenvironment of healthy individuals by increasing bacteria from the family Lachnospiraceae and SCFAs production. A randomized controlled trial reported that healthy adults supplemented with Bacillus subtilis (n = 76) experienced a reduction in gas-related GI symptoms. Another randomized controlled trial (n = 75) examined the effect of oral spore-based probiotic consisting of Bacillus indicus, Bacillus subtilis, Bacillus coagulans, Bacillus licheniformis, and Bacillus clausii on reducing dietary endotoxemia (the presence of LPS in the bloodstream). The study concluded that the 30-day spore-based probiotic supplementation may reduce intestinal-permeability-related complaints.
An intriguing therapeutic potential for Bacillus spp. may be related to their ability to interact with the internal environment of the host and produce antimicrobial peptides. An in vitro study revealed that Bacillus clausii may display protective qualities against the cytotoxic effects of Clostridium difficili and Bacillus cereus by secreting alkaline serine M-protease and the bacteriocin clausin, suggesting a role for Bacillus clausii in the management of C. difficile-associated diarrhea and other GI complaints. Another in vitro study demonstrated that Bacillus subtilis may secrete antibiotics that impede Helicobacter pylori and support a healthy inflammatory response.
Available research provides compelling evidence for the role of spore-based probiotics in supporting gut health. Further exploration in the form of human randomized controlled trials may be warranted in order to expand our understanding of their impact and mechanisms of action.
Learn more about spore-based probiotics:
Balance Bacteria with Spore-Based Probiotics
Dig Up the Dirt on Spore-Based Probiotics
By Antonia Toupet, PhD
Designs for Health has been dedicated to being the most trusted source for superior quality, science-based nutritional products for nearly three decades. We’re committed to maximizing successful health outcomes by providing healthcare practitioners with comprehensive support through our extensive product line, ongoing clinical education, and practice development programs. The blogs we publish here cover a range of topics, including new and original approaches to diet and healthcare, analyses of the latest cutting-edge research, deep-dives into specific nutrients, botanicals, nutraceuticals and more, all fully referenced for those who want to dig deeper into the primary literature.
