What Are Probiotics and Why Are They Beneficial?

What are the positive effects of Probiotics? – Should they be consumed with caution?

Appearing as a solution of modern days, probiotics and concepts (functional foods) involving the foods containing them have evolved significantly with consumers’ understanding of the link between achieving good health and food consumption. Since then, a series of controversies have popped up raising alarm concerning their usage. Similarly, their understanding of having an impact on individual gut microbiota together with the recent advances in food analysis has revealed the need for more evidences to claim their positive effects on health and evolve the concept of personalized nutrition.

What are the Probiotics (Or Foods Containing Them)?

Probiotics are non-pathogenic microorganisms that, when consumed in adequate amounts, confer health benefits to the hosts. They are yeasts or lactic acid bacteria such as Saccharomyces boulardii, or Lactobacillus and Bifidobacterium species respectively. After reaching their targeted places (Gastrointestinal tract), probiotics may help to maintain a healthy balance of microorganisms in the gut, which can in turn have positive effects on overall health. There are various mechanisms through which probiotics exert their benefits such as lowering the intestinal pH, decreasing colonization and invasion from pathogenic organisms, and modifying the host immune response (13). Indeed, the awareness of the implication of food consumption on achieving good health together with the increased healthcare cost has led to finding alternatives to reduce the risk or manage diseases. As part of these alternatives, the use of probiotics was suggested and shreds of evidence of their benefits were extensively documented [1, 3, 5, 8, 12]. At this point, the definition profiled by the International Scientific Association for Probiotics and Prebiotics (ISAPP), references them as a modern solution with claims to either alleviate or forestall all diseases, including diarrhea, obesity, Alzheimer and cancer.  Nevertheless, these views seem challenged until recently, even though pieces of evidence of their clinical uses could be found in the literature. Interestingly, in the present summary, we intend to bring together recent insights into the health benefits of probiotics with the hope of raising the need for more studies on which outcomes could encourage the prescription of probiotics for efficient and personalized treatments. However, with their (probiotics and products containing them) generally recognized as safe (GRAS) status, the usage of products containing them could be encouraged to grant good intestinal balance within microbiota at the household level.

 What are the top probiotic foods?

Fermented foods are high in probiotics as well. Common fermented foods that naturally contain probiotics, or have probiotics added to them, are yogurt, kefir, sauerkraut, kombucha, pickles, kimchi, miso, tempeh, sourdough bread and some raw cheeses.

What are probiotics good for?

The probiotics-related series of studies have strengthened the association of probiotics with maintaining and/or promoting well-being. This led to the development of different concepts of which functional foods and/or nutraceuticals have gained more interest in recent decades. From a food consumption perspective, it can be assumed that these concepts and probiotics understanding focus on the health benefits (beyond nutritional value) granted either by the microorganisms and/or by the food ingredients consumed in adequate amounts as a part of a diet. As for now, careful use of probiotics and foods containing them could be a valuable alternative to alleviate and cure the incidence of some diseases like obesity, diarrhea, antibiotic-associated diarrhea, Clostridium difficile disease, and cancer.  [1, 6, 12].

How do probiotics work?

The mechanisms of action behind the exerted health benefits, even though still unclear, could include the production of bacteriocin; the lowering of pH; the improvement of intestinal health; Immunoglobulin A (IgA) secretion; modifying T-cell responses, among others reported in [3, 5, 8]. The use of probiotics has been associated to alleviate the risk or manage the incidence of both gastrointestinal (GI) and non-gastrointestinal medical conditions [4, 6]. Evidence of using probiotics to manage GI medical conditions can be found in Table 1.

What is the role of probiotics in cancer prevention?

Slizewska et al. [10] appraised the role of probiotics in cancer prevention and concluded on the positive effect of Lacticaseibacillus rhamnosus GG in inhibiting and inducing apoptosis of cancer cells. The mechanism behind this lies in the production of short-chain fatty acids (SCFA), such as butyric acid, reportedly associated with the regulation of proliferation, division, and apoptosis of colon cells. Noteworthy, SCFAs are derived from the intestinal flora in insufficient amounts to inhibit the development of certain cancers. Thus, consuming probiotics on a daily basis can help improve the daily production of SCFAs.

Similarly, in some instances, a combined treatment of probiotics and transforming growth factor beta (TGF-ß) receptor blockers was found successful in inhibiting tumor growth. Nonetheless, despite the lack of a worldwide legal framework for consumer protection and safe probiotics usage [6, 7, 12] has reported that most probiotics are safe. Further insights into the health benefit associated with the consumption of probiotics and foods containing them can be found in Figure 1. Table 1 samples outcomes associated with the clinical uses of probiotics.

Figure 1: Health benefits associated with the consumption of probiotics and functional foods.

Table 1: Outcomes and probiotics strains tested

Who should not take probiotics or should consume them with caution?

With the lack of evidence confirming the safety of their administration versus the series of outcomes depicting their health benefits, care should be taken when administering probiotics to at-risk patients such as those immunocompromised, those with an abnormal gastrointestinal mucosal barrier, those with Small Intestinal Bacterial Overgrowth (SIBO) or FODMAPs intolerance, or even those recovering from surgery and at some instant, a gradual administration could be preconized. However, it is worth mentioning that most probiotics are GRAS, and the side effects (constipation, flatulence, nausea, rash) reported from their usage up to now are minor. Revealing the interaction between probiotic strains and gut microbiota could pave the way for their recognition as food-based drugs by the FDA.

Is it safe to use probiotics or products that contain probiotics?

Studies towards tackling the gap created by the lack of a worldwide legal framework for consumer protection and safe probiotics usage are needed. As for now, safe consumption of probiotics or probiotic-based foods (containing a mixture of probiotics) on a daily basis could be the new game changer in managing diseases and reducing the burden of high healthcare costs, especially in developing countries.

References

1. Anihouvi, E. S., & Kesenkaş, H. (2022). Effects of probiotic bacteria on microbiological, physico-chemical, and functional quality of Wagashi cheese. LWT – Food Science and Technology, 155.
2. Das, T. K., Pradhan, S., …. et al. (2022). Current status of probiotics and related health. Applied Food Research.
3. Fenster, k., Freeburg B., Hollard, C., Wong, C., Ronhave, L. R., Ouwehand, A. C. (2019). The production and delivery of probiotics: a review of a practical approach. Microorganisms, 7.
4. Ford, A. C., Harris, L.A., Lacy, B. E., Quigley, E. M. M., Moayyedi, P. (2018). Systematic review with meta-analysis: the efficacy of prebiotics, probiotics, synbiotics and antibiotics in irritable bowel syndrome. Aliment Pharmacol Ther, 48.
5. Granato, D., Barba, F. J., Bursac, K. D., Lorenco, J. M., Cruz, A. G., Putnik, P. (2020). Functional foods: product development technology trends, efficacy testing, and safety. Annu Rev Food Sci Technol 2020,11.
6. Islam, S. U. L. (2016). Clinical use of probiotics. Medicine.
7. Lu, K. Shanwu, D., Xiaoyan, W., Runming, G., Hongbo, C. (2021). Probiotics in Cancer. Frontiers in Oncology.
8. Ozen and Dinleyici (2015). The history of probiotics: the untold story. Beneficial microbes, 6:159-165.
9. Rondanelli, M., Faliva, M. A., Perna, S. Giacosa, A. Peroni, G., .… et al. (2017). Using probiotics in clinical practice: where are we now? A review of existing metaanalysis. Gut microbes.
10. Slizewska, K., Markowiak-Kopec, P., Slizewska, W. (2020). The role of Probiotics in Cancer Prevention. Cancers, 13:20.
11. Wicinski, M., Jakub G., Jakub, G., Bartosz, M. (2020). Probiotics for the Treatment of Overweight and Obesity in Humans—A Review of Clinical Trials.
12. Zucko, J., Antonio, S., Janko, D., Damir, O., Amir, M. M., Putnik, P. (2020). Probiotic- Friend or foe? Current Opinion in Food Science, 32.
13. Nancy, T. W. (2010). Probiotics. American Journal of Health-System Pharmacy, 67, 449–458. https://doi.org/10.2146/ajhp090168