Our ancestors lived in close contact with mother earth. Foods with clinging soil, untreated water, and “dirt” were all rich sources of bacteria. Certainly they might have come in contact with pathogenic organisms, but exposure to a variety of microbes during the early years of life would have strengthened their microbiome and immune system (1). Today hygiene is considered very important for maintaining good health, most of the food we eat are cleaned, pasteurized and/or processed, and the soil is damaged by pesticides, herbicides, and other man-made chemicals. How can we get the same benefits as our primal forefathers?
Some soil organisms are pathogenic in humans while others are considered beneficial. Today I’ll focus on one of the most studied strains which can be found in some probiotic supplements; Bacillus Subtilis.
Bacillus Subtilis has no adverse effects in humans. Researchers have found no pathogenic genes, and the strains have also been added to gut epithelial cells without causing any harm.
Antibiotic-resistant genes are found in some microbes, and when present in the gut these genes can potentially be passed on to pathogenic bacteria. All of the Bacillus Subtilis strains tested are sensitive to antibiotics which is a good thing (2-4,9).
Some soil organisms have the ability to form a tough, protective endospore, allowing the organism to tolerate extreme environmental conditions. Spores that are millions of years old have been found (6).
Spores of B. subtilis are fully resistant to SGF and bile salts which is important for a good probiotic strain. While spore forming bacteria aren’t necessarily able to permanently colonize the GI tract, probiotic effect may result from action at a variety of sites and a variety of mechanisms.
Bacillus Subtilis is an important part of the fermented food Natto, and the consumption of this traditional japanese food has been linked to several health benefits. Various strains of B. Subtilis have shown to be beneficial in humans (10-14), and a comprehensive clinical review showed that probiotic supplements with B. Subtilis improve symptoms of irritable bowel syndrome (10). It has also been shown that B.Subtilis suppresses the growth of harmful pathogens (11) and enhances the growth of Lactobacillus (12).
Some products are mislabeled with the species they contain (5,7), so it’s always best to look for a trusted manufacturer and possibly a product that has been assessed by an independent source.
While taking probiotic supplements containing soil organisms is one way to go, why not do it the natural way by eating “dirty” vegetables, mushrooms, fruits, berries and other foods from the garden or farmers market, getting water from a quality source, letting your kids play in the dirt, and avoiding excessive hygiene and harsh chemicals?
1: McDade, T.W., Rutherford J. , Adair, L, et al. Early origins of inflammation: microbial exposures in infancy predict lower levels of C-reactive protein in adulthood
Published online before print December 9, 2009, doi: 10.1098/rspb.2009.1795
2: Hong, H.A., Huang, J-M., Khaneja, R., Hiep, L.V., Urdaci, M.C. & Cutting, S.M.The Safety of Bacillus subtilis and Bacillus indicus as food probiotics.
Journal of Applied Microbiology 105: 510-520.
3: Sorokulova, I.B., Pinchuk, I.V., Denayrolles, M, Osipova,
I.G., Huang, J.M., Cutting, S.M. & Urdaci, M.C. (2008) The Safety of Two Bacillus Probiotic Strains for Human Use.
Digestive Diseases and Sciences 53: 954-963.
4: Tompkins, T.A., Hagen, K.E., Wallace, T.D. & Fillion-Forte,
V. (2008) Safety evaluation of two bacterial strains used in asian probiotic products. Canadian Journal of Microbiology. 54: 391-400.
5: Sanders, M.E., Morelli, L. & Tompkins, T.A. Sporeformers as Human Probiotics: Bacillus, Sporolactobacillus, and Brevibacillus. Comprehensive
Reviews in Food Science and Food Safety 2: 101-110.
6: Cano RJ, Borucki MK (1995) Revival and identification of bacterial spores in 25- to 40-million-year-old Dominican amber. Science 268: 1060-1064.
7: Green DH, Wakeley PR, Page A, et al. Characterization of two Bacillus probiotics.
Appl Environ Microbiol. 1999 Sep;65(9):4288-91.
8: McFarlane, G.T., Cummings, J.H., Allison, C. (1986) Protein degradation by human intestinal bacteria. J. Gen. Microbiol. 132, 1647–1656.
9: European Food Safety Authority (EFSA), 2010. Scientific opinion on the maintenance of the list of QPS microorganisms intentionally added to food or feed (2010 update). Panel on Biological Hazards. EFSA J 8(12):1944.
10: Tompkins T.A., Xu X. and Ahmarani J., 2010. A comprehensive review of of post-market clinical studies performed in adults with an asian probiotic formulation. Beneficial Microbes 1: 93-106.
11: ^ – Zhong, Y.T., Zhang, W.P., Wang, X.H., Huang, Z. and Ma, L.L., 2006. The bacteriostatic effect of Medilac-Vita on enteric pathogen and conditioned pathogen and their bacterial L form. Journal of Gannan Medical University 26: 487-488.
12: Hosoi T, Ametani A, Kiuchi K, et al. Improved growth and viability of lactobacilli in the presence of Bacillus subtilis (natto), catalase, or subtilisin.
Can J Microbiol. 2000 Oct;46(10):892-7.
11: Coppi F, Ruoppolo M, Mandressi A, et al. Results of treatment with Bacillus subtilis spores (Enterogermina) after antibiotic therapy in 95 patients with infection calculosis.
Chemioterapia. 1985 Dec;4(6):467-70.
12: Permpoonpattana P, Hong HA, Khaneja R, et al. Evaluation of Bacillus subtilis strains as probiotics and their potential as a food ingredient.
Benef Microbes. 2012 Mar 20:1-9. [Epub ahead of print]
13: Williams P. Bacillus subtilis: a shocking message from a probiotic.
Cell Host Microbe. 2007 Jun 14;1(4):248-9.
14: Selvam R, Maheswari P, Kavitha P, et al. Effect of Bacillus subtilis PB6, a natural probiotic on colon mucosal inflammation and plasma cytokines levels in inflammatory bowel disease.Indian J Biochem Biophys. 2009 Feb;46(1):79-85.