The microbiome, the diverse community of microorganisms that inhabit our bodies, has evolved into a fascinating field of research that reveals an impressive range of effects on our health and well-being. In the midst of this microcosm of microorganisms, interest in probiotics has increased in recent years.
What are probiotics and what are their effects?
Probiotics are “live microorganisms which, when administered in sufficient quantities, confer a health benefit on the host”. The most commonly used probiotics belong to the genus Lactobacillus , Bacillus , Bifidobacterium , and Saccharomyces . The dose given in probiotic food supplements is always given in "colony forming units (cfu)". This describes the number of living and active microorganisms in a serving in a probiotic dietary supplement.
Various potential mechanisms of action for probiotics are known, but the effect depends on the bacterial genus or the bacterial species. Mechanisms include modulation of the immune system, direct interaction with the gut microbiome, support of barrier function, and production of short-chain fatty acids, enzymes, and molecules with systemic effects such as neurotransmitters.(1) How do probiotics affect our health?
Probiotics can improve immune function by stimulating B cells to produce IgA. They also influence signaling pathways of pro- and anti-inflammatory cytokines that modulate immune function. Some probiotics like Streptococcus and Lactobacillus can reduce pro-inflammatory cytokines like TNF-alpha and interleukin-6, others increase the production of anti-inflammatory cytokines like interleukin-10 or TGF-beta. In addition, probiotics affect gut barrier function, as some probiotic bacteria increase the production of mucins and tight junction proteins, which are important for maintaining gut barrier function.(2)
Probiotic bacteria belonging to the genus Bifdobacterium and Lactobacillus produce lactic acid and acetic acid as the primary end products of carbohydrate metabolism. Various in situ model systems showed that these organic acids lower the pH in the lumen of the gut and inhibit the growth of pathogenic microorganisms. Lactobacillus and Bifidobacterium do not produce butyrate but do so by feeding other commensal bacteria, such as Faecalibacterium the level of butyrate and other short-chain fatty acids in the intestine may increase. This can affect various aspects of physiology and is related, for example, to an improved insulin response.(3)
There is growing evidence that the state of our gut microbiome has an impact on mental health. The interactions through the gut-brain axis also give the possibility of using probiotics here. Irritable bowel syndrome (IBS) is a complex disease that can cause a variety of symptoms, such as abdominal pain, bloating, diarrhea or constipation. The exact cause of irritable bowel syndrome is not yet fully understood, but the gut-brain axis is also important here.(4) Studies have shown that Lactobacillus plantarum can help with irritable bowel symptoms such as bloating and abdominal pain.(5), (6 )
The future of probiotics
As knowledge about the human microbiome and its functions continues to expand, the future holds a number of potential new probiotic bacteria, such as Roseburia intestinalis , Faecalibacterium prausnitzii , Eubacterium spp ., Bacteroides spp. and Akkermansia muciniphila .(7) These bacterial species have physiological functions not covered by Bifidobacterium or Lactobacillus species, such as the production of the short-chain fatty acids butyrate and propionate.(8) Akkermansia muciniphila has increasingly gained interest due to its health-promoting effects and role in metabolic diseases such as obesity and insulin resistance. For example, in one study in obese and insulin-resistant participants, Akkermansia muciniphila supplementation showed increased insulin sensitivity.(9)
The mechanisms of action of probiotics are complex, heterogeneous and mostly bacteria specific and not all mechanisms have been confirmed in human studies. Although many probiotics have been evaluated, there is still a need for a better understanding, particularly explanations for the structure and function of the observed health effects and long-term effects. More clinical studies are needed to confirm the beneficial effects of probiotics in treating specific diseases. (10)
Note: This article is for informational purposes only and should not be construed as medical information or instruction. The recipes are for inspiration and are not intended as a therapeutic measure. If you have health problems, we recommend that you contact a doctor or other expert immediately.
Request more information. First free consultation!
Gabriela De Pasquale
Nutritional Consultation
Estepona, Spain
+34 604398948
References
(1) ME Sanders, DJ Merenstein, G Reid, GR Gibson, and RA Rastall, "Probiotics and prebiotics in intestinal health and disease: from biology to the clinic," Nat Rev Gastroenterol Hepatol , vol. 16, no. 10, pp. 605-616, Oct. 2019, doi: 10.1038/s41575-019-0173-3.
(2) C. Mazziotta, M. Tognon, F. Martini, E. Torreggiani, and JC Rotondo, "Probiotics Mechanism of Action on Immune Cells and Beneficial Effects on Human Health," Cells , vol. 12, no. 1. MDPI, Jan. 01, 2023. doi: 10.3390/cells12010184.
(3) S. Sanna et al. , “Causal relationships among the gut microbiome, short-chain fatty acids and metabolic diseases,” Nature Genetics , vol. 51, no. 4. Nature Publishing Group, pp. 600–605, Apr. 01, 2019. doi: 10.1038/s41588-019-0350-x.
(4) E. Simon, LF Călinoiu, L. Mitrea, and DC Vodnar, "Probiotics, prebiotics, and synbiotics: Implications and beneficial effects against irritable bowel syndrome," Nutrients , vol. 13, no. 6. MDPI, Jun. 01, 2021. doi: 10.3390/nu13062112.
(5) P Ducrotté, P Sawant, and V Jayanthi, "Clinical trial: Lactobacillus plantarum 299v (DSM 9843) improves symptoms of irritable bowel syndrome," World J Gastroenterol , vol. 18, no. 30, pp. 4012–4018, 2012, doi: 10.3748/wjg.v18.i30.4012.
(6) K Niedzielin, H Kordecki, and B Birkenfeld, "A controlled, double-blind, randomized study on the efficacy of Lactobacillus plantarum 299V in patients with irritable bowel syndrome," European journal of gastroenterology & ; hepatology , vol. 13, no. 10, p. 1143-1147, Oct. 2001, doi: 10.1097/00042737-200110000-00004.
(7) M. Cunningham et al. , “Shaping the Future of Probiotics and Prebiotics,” Trends in Microbiology , vol. 29, no. 8. Elsevier Ltd, pp. 667–685, Aug. 01, 2021. doi: 10.1016/j.tim.2021.01.003.
(8) EE Blaak et al. , “Short chain fatty acids in human gut and metabolic health,” Beneficial Microbes , vol. 11, no. 5, pp. 411–455, Aug. 2020.
(9) C. Depommier et al. , “Supplementation with Akkermansia muciniphila in overweight and obese human volunteers: a proof-of-concept exploratory study,” Nat Med , vol. 25, no. 7, pp. 1096–1103, Jul. 2019, doi: 10.1038/s41591-019-0495-2.
(10) J. Suez, N. Zmora, E. Segal, and E. Elinav, "The pros, cons, and many unknowns of probiotics," Nature Medicine , vol. 25, no. 5. Nature Research, pp. 716–729, May 01, 2019. doi: 10.1038/s41591-019-0439-x.
