The human gut contains the body’s richest composition of microbial organisms. Probiotics aim to change the intestinal microbiota. They are living organisms, mostly bacteria, that benefit health if ingested in adequate amounts. Probiotics are naturally found in fermented foods and are also available in the form of dietary supplements. (Source)
The normal gut microbiota can be disturbed in many ways, such as by diseases, medical treatments, and lifestyle changes. Probiotics have been used to restore healthy intestinal microbiota, but their efficacy is still being investigated. Soil-based probiotics have started gaining popularity in probiotic research because they may have better stability and survivability in the gastrointestinal environment than other probiotics. In this article, we’ll discuss the applications and potential benefits of soil-based probiotics and what you should consider before trying them.
What Are Probiotics?
Probiotics are organisms that help change gut microbiota for the host’s benefit. Commonly used probiotics include genera of Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus and Bacillus.
Probiotics may benefit health by:
- producing organic acids such as acetic, butyric, and lactic acid, which help improve mucosal immune system of the gut
- producing antimicrobials
- preventing or minimizing pathogen colonization
- improving intestinal barrier function
Soil-based probiotics for human use consist of mostly Bacillus probiotic strains and others such as Enterococcus faecium, Enterococcus faecalis, and Clostridium butyricum. They are found in soil, fermented foods, air, and the human gut microbiota. (Source, Source)
Soil-based probiotics have been used in treating animals, food fermentation, and even the production of vitamins and other nutraceuticals. Although research has been increasing in the last decade, more research needs to be done to understand the probiotic potential and safety of human health.
What Are Soil-based Probiotics?
Soil-based probiotics are living organisms that are found naturally in soil. Your diet likely includes soil-based probiotics from vegetables and other foods that grow low to the ground. Non-soil based probiotics are found in various environments such as air, water, and the intestinal tracts of animals, including humans. (Source)
Probiotics are living organisms, and to be effective they must be able to survive processing, storage, and harsh conditions in the stomach. Soil-based probiotics form spores, or tough outer coatings, that are resistant to extreme conditions. Research suggests the stability of soil-based probiotics is high in heat, moisture, and stomach conditions. One study in mice showed B. cereus bacteria persisted in the mouse gastrointestinal tract for up to 18 days, showing they were able to survive and reproduce. Spore-forming bacteria won’t need refrigeration and have a longer shelf life. (Source, Source, Source)
Commercial Types of Soil-based Probiotics
Bacillus species are associated with the fermentation of soy, maize, and rice. Natto, soibum, and ugba are examples of Bacillus-fermented foods consumed in Japan, India, and Nigeria, respectively. Commercial Bacillus probiotics are B. clausii, B. coagulans, B. licheniformis, B. polyfermenticus, and B. subtilis. Let’s look at the research behind potential probiotics effects of each Bacillus species.
B. clausii is one of the widely used Bacillus strains due to its anti-inflammatory and antibacterial effects. A pilot study published in Therapeutics and Clinical Risk Management assessed the efficacy of B. clausii spores given as an oral solution to children with recurrent respiratory infections. The children receiving the B. clausii spores had fewer respiratory infections than an untreated control group, and when they did become ill they recovered more quickly. There were no adverse effects noted. (Source)
B. coagulans is a probiotic naturally found in your body. It produces lactic acid, which has beneficial effects on gut health. On the market, B. coagulans is sometimes misclassified as lactobacillus, which is also a lactic acid producer. However, B. coagulans forms spores while lactobacillus doesn't. (Source)
Effects of B. coagulans on irritable bowel syndrome (IBS) symptoms were investigated in a randomized, double-blind, and placebo-controlled clinical trial. The B. coagulans LBSC strain was given to 20 male and female adults with IBS who had symptoms such as abdominal discomfort, cramping, bloating, and change in bowel habits for more than 3 months. Eighty days of treatment with B. coagulans significantly improved abdominal pain, nausea, diarrhea, and constipation, with no adverse events reported. (Source)
Other B. coagulans strains researched in human studies include MTCC 5856, which was shown to improve diarrhea, bloating, vomiting, stool frequency, and abdominal pain related to IBS, and SNZ 1969, which minimized symptoms of bacterial vaginosis. (Source, Source)
The most common dosage of B. coagulans is 1–2 billion colony-forming units (CFUs) orally for 1 to 3 months. However, you should always consult your health care provider for guidance on usage and proper dosage. It’s important to note that so far research hasn’t established the safety of B. coagulans probiotics for use in pregnancy and breast-feeding. (Source)
B. licheniformis is used in biotechnology to produce enzymes, antibiotics, and biochemicals. Unlike most bacillus species, B. licheniformis is a facultative anaerobe, meaning it can grow in both the presence and the absence of oxygen. (Source)
An animal study published in Nutrients evaluated B. licheniformis effects on rat gut microbiota balance. Psychological stress was induced in rats for 4 weeks, and they were exposed to excessive antibiotics for 1 week. After, they were given B. licheniformis as a treatment for 1 month. Results showed that B. licheniformis significantly reduced serum TNF-alpha, a pro-inflammatory cytokine. B. licheniformis also changed the gut microbiota. Beneficial genera of bacteria, such as Ruminococcaceae and Lachnospiraceae, increased. In contrast, harmful genera of bacteria, such as Pasteurella, decreased. (Source)
Anticarcinogenic effects of B. polyfermenticus SCD were researched on the Caco-2 cell line isolated from a human colon adenocarcinoma, cancer generated from glands. Caco-2 cells treated with B. polyfermenticus SCD showed a decrease in cell growth. In the same study, colon lesions were induced in male rats using chemicals. After 10 weeks of B. polyfermenticus SCD treatment, lesions decreased by 40% compared to a control group. (Source)