Top Probiotic Strains and their Differences

Everyone has a unique composition of microflora in every area of their bodies that cohabitate in a complex ecosystem of symbiotic relationships. The high diversity between individuals is caused by the fact that the microbiome has roughly ten times the number of genes as the human genome, allowing for greater flexibility and interaction over evolutionary history. Probiotic organisms have been found to have extensive antimicrobial effects, such as by creating antitoxins, inhibiting pathogens, and producing important bile acids, vitamins and other nutrients in the GI tract. Probiotics generally strengthen the mucosal barrier and improve its function through several mechanisms. In the following article, we will examine the role of the major strains of beneficial microflora: Bifidobacterium and Lactobacilli.  

Bifidobacterium

Bifidobacteria are anerobic saccharolytic bacteria that are the primary means by which the body breaks down monosaccharides. Bifidobacterium are found predominantly in the gut where they constitute over 95% of the intestinal flora in breast-fed infants and their presence is linked to numerous host benefits through development (1). Next-generation DNA sequencing and genome methodologies have uncovered the genetic diversity of Bifidobacterium and the specific genetic traits that aid in their establishment and interactions within the gut.

• Bifidobacterium metabolize non-digestible carbohydrates, producing growth substrates for other gut bacteria.

• They engage in cooperative interactions and cross-feeding strategies, dependent on other bacteria to access certain glycans, shaping the gut microbiota composition.

What’s the Difference Between Strains of Bifidobacterium?

Bifidobacterium Bifidum

Bifidobacterium Bifidum has been studied due to the role it is believed to have had in the evolution of the immune system. B, Bifidum has the interesting ability to break down mucin, which is the main component of the GI tract’s mucus lining. Because mucin is made of carbohydrate monomers, like glucosamine and galactose, the B. Bifidum’s digestion enables release of energy and degradation of oligosaccharises (2). This strain of Bifidobacterium also has shown to have immunomodulatory activity, and to activate TNF-alpha and IL-17 cytokines (2). Other studies  have found that B. Bifidum is capable of out-competing pathogenic strains of bacteria, such as H. pylori (9).

Bifidobacterium Breve

This strain is one of the most used in pediatric health, as it is the dominant human breast milk species of Bifidobacteria. It has been found to have antimicrobial activity against pathogens, and immune system stimulation properties, leading it to be of interest to the emerging discipline of therapeutic microbiology (5).  Like other Bifidobacterium species, B. Breve contain many enzymes for digesting various carbohydrates, such as galactosidase that digest oligosaccharides and lipids in the mucosal lining. B. Breve showed an improved effect over B. Longum in colonizing the infant intestinal microflora, and high antimicrobial activity against gut pathogens (5). Other studies have found that it inhibited Enterobacteriaceae and faecal coliforms in healthy children. They also found that it was able to ferment soymilk into a probiotic beverage with anticancer and lipid metabolism effects (5).

In mice models, the effects are more pronounced and supportive of the antimicrobial roles of B. Breve. When combined with beta-lactoblogulin, this strain was found to increase IL-22 expression, which is involved in the innate immunity and IL-10, the cytokine in Peyer’s patches (11). B. Breve also increased IL-10, produced immune cells, increased mechanisms that protected against obesity, and also regulated gene expression pathways that control liver stress response and lipid processing (11).

Bifidobacterium Longum

1. Longum has shown to have multiple beneficial effects in remediating immune disfunction, infectious disease and GI problems. These effects are largely due to its system-wide effects on the human microbiome (10). It has even been found to inhibit cancer that was induced in mice (3). In one study, the administration of a cancer-causing agent to untreated mice induced cancers in the liver, intestines, and mammary glands. However administration of B. longum BB536 inhibited cancers in all these organs, and notably a 100% inhibition in the large intestine (3).

Bifidobacteria are the first to colonize the infant Gi tract, and create metabolites that allow for the colonization by other bacterial populations. Other mutual benefits between these different bacteria have been discovered, such as the ability to the organism, Bacteriodes thetaiotaomicron to digest polysaccharides only in the presence of B. longum (6). This make B Longum an important probiotic for supplementation.

By examining the prebiotic metabolism, scientists have been able to obtain evidence of cross feeding between B. longum and E. rectale, between Bifidobacterium and Bacteroides, and between Bifidobacterium and F prausnitzii. Some researchers have used a proteomic analysis, showing that B. longum and B. breve interact to produce enzymes that breakdown oligosaccharides, suggesting a cooperation between species to improve the body’s use of carbohydrates. This highlights the symbiotic relationship between species and the dependence humans and many other animals have on their microbiome.

 Bifidobacterium Infantis

Bifidobacterium Infantis is actually a subspecies of B. Longum, unique in its ability to digest any oligosaccharides in breast milk and showing a higher growth rate than other bifidobacterium in the presence of human milk (12). The reason is that gene sequencing found a gene cluster known as HMO cluster 1, ont found in other species, that encodes for a set of proteins that transport oligosaccharides. Only B. infantis can digest all of the oligosaccharides.

What is truly special about this subspecies is that it was one of the best at digesting prebiotic milk glycans, allowing it to outcompete other bifidobacteria and pathogens. In general, the strain was found to have anti-inflammatory activity in animal studies, such as suppression of proinflammatory cytokines IL-6 and IL-8, and toll-like receptors TLR2 and TLR4. Another important function of B. infantis is its ability to repair intestinal permeability (13).

Lactobacillus

Lactobacillus is a genus of beneficial bacteria that is commonly found in the human gut, mouth, and female genital tract. It plays a crucial role in maintaining a balanced microbial environment in these areas, which is essential for overall health.

Lactobacillus acidophilus

L. acidolphilus has been one of the most popular probiotics, and has a long history of use in treating intestinal dysbiosis. However, it has also been found to help heal liver injury (25). The benefits include the prevention of a loss of beneficial organisms, the prevention of the growth of pathogenic organisms, and the preservation of the total diversity of microorganisms. Several studies have found that probiotic organisms have different effects on cancer cells than normal cells, and have multiple beneficial effects on the immune system, both through primary effects in the modulation of mucosal immunity, and in the creation of secondary metabolites and polysaccharides that have anti-tumor activity (3).

Lactobacillus Plantarum

In one study, Lactobacillus plantarum was found to induce apoptosis in oral cancer cell lines. (3). The authors followed and confirmed similar previous studies, but also sought to determine the mechanisms behind these anti-cancer effects. They discovered that Lactobacillus Plantarum modulated the cell signal transduction pathways, specifically by downregulating the MAPK gene, high levels of which are linked to angiogenesis and inhibition of cancer cell death (3). It also upregulated the PTEN gene, which is critical to the inhibition pathway.  

Lactobacillus Reuteri

Lactobacillus reuteri is a specific strain of Lactobacillus that has been discovered to be indigenous to the human GI tract. It offers a wide range of health benefits and can only be found in raw milk products, or supplements. There is emerging evidence that L. reuteri can help in weight management by influencing gut microbiota composition and enhancing metabolic functions (23). It may also play a role in regulating blood sugar levels, making it beneficial for individuals with diabetes. And there is also some evidence suggesting that L. reuteri can influence the gut-brain axis and contribute to improved mood and reduced symptoms of anxiety and depression (24).

Gut Health

Lactobacillus reuteri has been shown to be effective in preventing and treating various types of diarrhea, including acute infectious diarrhea and antibiotic-associated diarrhea¹⁵.Studies have demonstrated that L. reuteri can significantly reduce crying time in infants with colic, providing relief to both infants and their parents¹⁶.This probiotic can also help reduce Helicobacter pylori infections, which are associated with ulcers and stomach cancer¹⁷.Beyond outcompeting pathogens, L. reuteri has system-wide immune-boosting effects.

Immune System Support

Lactobacillus reuteri can enhance the immune system by stimulating the production of immune cells and increasing the body's ability to fight off infections¹⁸. It helps in reducing inflammation, which can be beneficial for conditions like inflammatory bowel disease (IBD) and other inflammatory conditions¹⁹.  L. reuteri can inhibit the growth of harmful bacteria in the mouth, thereby reducing dental plaque and the risk of cavities²⁰, and can also help improve gum health and reduce the symptoms of gingivitis²¹. Given the increasingly understood role of oral health in overall immunity, it is not surprising that L. reuteri shows promise in preventing and treating immune dysfunction by treating oral dysbiosis.

 

Supplementing Probiotics

If you are looking for strain-specific probiotics, a few companies are providing straight powder with no fillers or additives. One of the best right now is Custom Probiotics, which features all of the strains mentioned in this article, and allows individual to customize their own probiotic with their choice of strains. 

What is Kefir?

Kefir is another inexpensive option for probiotic supplementaiton, with the huge advantage of having all of the strains in the proper proportions. Kefir is a fermented milk drink that originates from the Caucasus Mountains and composed of a polysaccaride complex formed into "grains". These robust colonies ferment the milk, resulting in a thick, tangy beverage that contains a diverse range of beneficial bacteria and yeasts, including Lactobacillus, Bifidobacterium, and Saccharomyces species. These probiotics can help balance the gut microbiota and provide numerous benefits to the immune system.

Conclusion

Probiotics have a wide range of benefits and many modes of action. The main benefit is their immunomodulatory ability, by adhering to the epithelium lining, they can increase short-chain fatty acids (SCFA), while reducing inflammatory cytokines, regulating T lymphocytes, and increaseing production of immunoglobulins, which have been found to improve outcomes in infections and cancer (27). While there are many probiotic species, the main two Lactobaccilus and Bifidobacterium, have the highest efficacy and research supporting their use.

 

 

 

References

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3) Asoudeh-Fard, A., Barzegari, A., Dehnad, A., Bastani, S., Golchin, A., & Omidi, Y. (2017). Lactobacillus plantarum induces apoptosis in oral cancer KB cells through upregulation of PTEN and downregulation of MAPK signalling pathways. BioImpacts: BI, 7(3), 193.
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