Posts

Bacterial vesicles: Emerging potential postbiotics

By Dr. Gabriel Vinderola, PhD,  Associate Professor of Microbiology at the Faculty of Chemical Engineering from the National University of Litoral and Principal Researcher from CONICET at Dairy Products Institute (CONICET-UNL), Santa Fe, Argentina

The recently published ISAPP consensus paper defines a postbiotic as “a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host“. Such a definition quickly brings to mind that a postbiotic is not equivalent to microbial metabolites. A postbiotic should also contain inanimate microbial cells or cell fragments. Metabolites or fermentation products may be present, but they are not required.

Because microbes are complex entities, we must be open to innovative understandings of what a postbiotic might entail. Indeed, although not explicitly mentioned in the ISAPP consensus paper, extracellular membrane vesicles may comprise an innovative conceptualization of a postbiotic, falling within the ‘cell component’ part of the postbiotic definition.

Bacterial vesicles

Extracellular membrane vesicles (EMV) are universal carriers of biological information produced in all domains of life. Bacterial EMV are small, spheroidal, membrane-derived proteoliposomal nanostructures, typically ranging from 25 – 250 nm in diameter, containing proteins, lipids, nucleic acids, metabolites, numerous surface molecules and many other biomolecules derived from their progenitor bacteria (Figure 1). Bacterial vesicles have been known for more than 50 years as structures able to carry cellular material (Ñahui Palomino et al. 2021).  However, studies on membrane vesicles derived from Gram-positive bacteria are more recent as it was for a time believed they were incapable of producing vesicles due to their thick and complex cell walls, and the lack of an outer membrane. Today, EMVs have been isolated from Gram-positive probiotic bacteria, including those belonging to the Lactobacillaceae family (under which Lactobacillus was recently split into many new genera) and the Bifidobacterium genus. In probiotic bacteria, vesicles may mediate quorum sensing and material exchange. Perhaps even more important, they can act as mediators of bacteria-to-cell and bacteria-to-bacteria interactions. As bacterial EMV are inanimate structures that cannot replicate, they fit the postbiotic definiton as cell components as long as other criteria stipulated by the definition are met.

Figure 1. Membrane vesicles budding on the surface of L. reuteri DSM 17938 and released into the surrounding medium. These vesicles were described in by Grande et al. 2017. Photo used with permission of BioGaia.

Functions of bacterial vesicles related to potential health benefits

Underlying mechanisms and corresponding molecules driving health effects of bacterial vesicles are not well understood, in part due to reliance on in vitro models. Bacterial EMV derived from Lactobacillaceae spp., Bifidobacterium spp., and Akkermansia spp. have been reported to alleviate metabolic syndrome and allergy symptoms, promote T-cell activation and IgA production, strengthen gut barrier function, and exhibit anti-viral and immunomodulatory properties (Kim et al. 2016; Tan et al. 2018; Ashrafian et al. 2019; Molina-Tijeras et al. 2019; Palomino et al. 2019; Shehata et al. 2019; Bäuerl et al. 2020). Interestingly, vesicles from Limosilactobacillus reuteri DSM 17938 (West et al. 2020) and Lacticaseibacillus casei BL23 (Domínguez Rubio et al. 2017) may accomplish some of the the effects of these probiotic bacteria. In fact it is not unreasonable to think that EMVs may be already present and active in probiotic products.

Challenges for bacterial vesicle production

To develop a postbiotic from microbial EMVs, many challenges need to be overcome.  Defining optimal cultivation conditions, and methods for vesicle release, isolation and scaling up are some of the challenges of bacterial vesicle production. There are several studies showing that altering the cultivation parameters can impact vesicle production. Examples of treatments shown to increase vesicle release include exposure to UV radiation and antibiotic pressure (Gamalier et al. 2017; Gill et al. 2019). Exposure to glycine has also been shown to increase vesicle production (Hirayama & Nakao 2020). Interventions during culture, for example by introducing agitation and varying pH, can possibly be ways to potentiate vesicle release and increase their bioactivity (Müller et al. 2021). A recent report also revealed that B. longum NCC2705 released a myriad of vesicles when cultured in human fecal fermentation broth, but not in basal GAM anaerobic medium (Figure 1). Moreover, the B. longum vesicle production pattern differed among individual fecal samples suggesting that metabolites derived from symbiotic microbiota stimulate the active production of vesicles in a different manner (Nishiyama et al. 2020). Whether any of these treatments and culture conditions are general or strain specific remains to be elucidated. Large differences in the number of vesicles that may be obtained by different extraction methods can occur (Tian et al. 2020). Tangential flow filtration or the use of antibodies targeting specific epitopes of the vesicles are some of the options proposed for the large scale isolation of EMV (Klimentová & Stulík 2015).

Figure 2. Left: Bifidobacterium longum NCC2705 grown on GAM broth. Right: secretion of membrane vesicles by Bifidobacterium longum NCC2705: the strain was cultured in bacterial-free human fecal fermentation broth and secreted a myriad of membrane vesicles. Reported and adapted from Nishiyama et al. 2020.

Progress has been made on the production of bacterial vesicles in recent years, yet several issues remain to be clarified including how vesicles are generated from the progenitor microbe, how the composition of vesicles changes according to the culture conditions, how to target specific bacterial vesicle purification from a pool of vesicles derived from other organisms (for example, bacterial vesicles produced in milky media can be accompanied by vesicles from eukaryotic cells present in the milk), safety aspects, quantification methods and the regulation of their use by the corresponding authority.

Their future as potential postbiotics

Membrane vesicles are an exciting opportunity for the development of postbiotics. A potential benefit of vesicles is that their small size compared to whole cells may enable them to more readily migrate to host tissues that could not be otherwise reached by a whole cell (Kulp & Kuehn 2010). Their nanostructure enables them to penetrate through the gut barrier and to be delivered to previously unreachable sites through the bloodstream or lymphatic vessels, and to interact with different cell types (Jones et al. 2020). For example, bacterial rRNA and rDNA found in the bloodstream and the brain of Alzheimer’s patients were postulated to have originated from bacteria vesicles (Park et al. 2017). Safety of EMVs must be carefully considered and assessed, even if they are derived from microbes generally recognized as safe, as their small size may increase penetration capacity with potential and yet unknown systemic effects. Novel postbiotics derived from microbial membrane vesicles is an intriguing area for future research to better understand production parameters, safety and functionality.

Thanks to Cheng Chung Yong, postdoctoral researcher at Morinaga Milk Industry Co., LTD (Japan) and Ludwig Lundqvist, industrial PhD student at BioGaia AB (Sweden) for their contributions to this blog, and Mary Ellen Sanders and Sarah Lebeer from ISAPP for fruitful discussions.

References

Ashrafian, F., Shahriary, A., Behrouzi, A., Moradi, H.R., Keshavarz Azizi Raftar, S., Lari, A., Hadifar, S., Yaghoubfar, R., Ahmadi Badi, S., Khatami, S. and Vaziri, F., 2019. Akkermansia muciniphila-derived extracellular vesicles as a mucosal delivery vector for amelioration of obesity in mice. Frontiers in microbiology10, p.2155.

Bäuerl, C., Coll-Marqués, J.M., Tarazona-González, C. and Pérez-Martínez, G., 2020. Lactobacillus casei extracellular vesicles stimulate EGFR pathway likely due to the presence of proteins P40 and P75 bound to their surface. Scientific reports10(1), pp.1-12.

Domínguez Rubio, A.P., Martínez, J.H., Martínez Casillas, D.C., Coluccio Leskow, F., Piuri, M. and Pérez, O.E., 2017. Lactobacillus casei BL23 produces microvesicles carrying proteins that have been associated with its probiotic effect. Frontiers in microbiology8, p.1783.

Gamalier, J.P., Silva, T.P., Zarantonello, V., Dias, F.F. and Melo, R.C., 2017. Increased production of outer membrane vesicles by cultured freshwater bacteria in response to ultraviolet radiation. Microbiological research194, pp.38-46.

Grande, R., Celia, C., Mincione, G., Stringaro, A., Di Marzio, L., Colone, M., Di Marcantonio, M.C., Savino, L., Puca, V., Santoliquido, R. and Locatelli, M., 2017. Detection and physicochemical characterization of membrane vesicles (MVs) of Lactobacillus reuteri DSM 17938. Frontiers in microbiology8, p.1040.

Gill, S., Catchpole, R. & Forterre, P., 2019. Extracellular membrane vesicles in the three domains of life and beyond. FEMS microbiology reviews, 43(3), pp.273–303.

Hirayama, S. & Nakao, R., 2020. Glycine significantly enhances bacterial membrane vesicle production: a powerful approach for isolation of LPS-reduced membrane vesicles of probiotic Escherichia coli. Microbial biotechnology, 13(4), pp.1162–1178.

Jones, E.J., Booth, C., Fonseca, S., Parker, A., Cross, K., Miquel-Clopés, A., Hautefort, I., Mayer, U., Wileman, T., Stentz, R. and Carding, S.R., 2020. The uptake, trafficking, and biodistribution of Bacteroides thetaiotaomicron generated outer membrane vesicles. Frontiers in microbiology11, p.57.

Kim, J.H., Jeun, E.J., Hong, C.P., Kim, S.H., Jang, M.S., Lee, E.J., Moon, S.J., Yun, C.H., Im, S.H., Jeong, S.G. and Park, B.Y., 2016. Extracellular vesicle–derived protein from Bifidobacterium longum alleviates food allergy through mast cell suppression. Journal of Allergy and Clinical Immunology137(2), pp.507-516.

Kulp, A. & Kuehn, M.J., 2010. Biological functions and biogenesis of secreted bacterial outer membrane vesicles. Annual review of microbiology, 64, pp.163–184.

Molina-Tijeras, J.A., Gálvez, J. & Rodríguez-Cabezas, M.E., 2019. The immunomodulatory properties of extracellular vesicles derived from probiotics: a novel approach for the management of gastrointestinal diseases. Nutrients, 11(5), p.1038.

Müller, L., Kuhn, T., Koch, M. and Fuhrmann, G., 2021. Stimulation of probiotic bacteria induces release of membrane vesicles with augmented anti-inflammatory activity. ACS Applied Bio Materials4(5), pp.3739-3748.

Ñahui Palomino, R.A., Vanpouille, C., Costantini, P.E. and Margolis, L., 2021. Microbiota–host communications: Bacterial extracellular vesicles as a common language. PLoS Pathogens17(5), p.e1009508.

Nishiyama, K., Takaki, T., Sugiyama, M., Fukuda, I., Aiso, M., Mukai, T., Odamaki, T., Xiao, J. Z., Osawa, R., & Okada, N. 2020. Extracellular vesicles produced by Bifidobacterium longum export mucin-binding proteins. Applied and Environmental Microbiology, 86(19), e01464-20.

Palomino, R.A.Ñ., Vanpouille, C., Laghi, L., Parolin, C., Melikov, K., Backlund, P., Vitali, B. and Margolis, L., 2019. Extracellular vesicles from symbiotic vaginal lactobacilli inhibit HIV-1 infection of human tissues. Nature communications10(1), pp.1-14.

Park, J.Y., Choi, J., Lee, Y., Lee, J.E., Lee, E.H., Kwon, H.J., Yang, J., Jeong, B.R., Kim, Y.K. and Han, P.L., 2017. Metagenome analysis of bodily microbiota in a mouse model of Alzheimer disease using bacteria-derived membrane vesicles in blood. Experimental neurobiology26(6), p.369.

Shehata, M.M., Mostafa, A., Teubner, L., Mahmoud, S.H., Kandeil, A., Elshesheny, R., Boubak, T.A., Frantz, R., Pietra, L.L., Pleschka, S. and Osman, A., 2019. Bacterial outer membrane vesicles (omvs)-based dual vaccine for influenza a h1n1 virus and mers-cov. Vaccines7(2), p.46.

Tan, K., Li, R., Huang, X. and Liu, Q., 2018. Outer membrane vesicles: current status and future direction of these novel vaccine adjuvants. Frontiers in microbiology9, p.783.

Tian, Y., Gong, M., Hu, Y., Liu, H., Zhang, W., Zhang, M., Hu, X., Aubert, D., Zhu, S., Wu, L. and Yan, X., 2020. Quality and efficiency assessment of six extracellular vesicle isolation methods by nano-flow cytometry. Journal of extracellular vesicles9(1), p.1697028.

West, C.L., Stanisz, A.M., Mao, Y.K., Champagne-Jorgensen, K., Bienenstock, J. and Kunze, W.A., 2020. Microvesicles from Lactobacillus reuteri (DSM-17938) completely reproduce modulation of gut motility by bacteria in mice. PloS one15(1

Opportunity for research grants to help understand evidence linking live dietary microbes and health

For thousands of years, cultures across the globe have been consuming fermented foods, many of which contain diverse and numerous live microbes. Yet scientists are still puzzling over whether a greater intake of live microbes results in measurably better health. As part of long-term efforts to understand evidence for the health benefits of live dietary microbes and identify research gaps, ILSI North America is presenting a grant opportunity for researchers to help assess current scientific evidence for these links.

Researchers are invited to submit grant proposals, which should include the research approach along with anticipated challenges, resources, timeline, and key deliverables. The ILSI North America Gut Microbiome Committee also requests the inclusion of a suggested publication plan for the work. Budgets in the range of $100-150K will be considered. The deadline to submit the proposal is October 30, 2020 at 11:59PM EST. See here for more details.

ISAPP is supporting long-term efforts in this topic area. Its latest effort is the publication of a review paper (in press) on the links between dietary live microbes and health, called Should there be a recommended daily intake of microbes? The paper is authored by ISAPP board members Prof. Maria Marco, Prof. Colin Hill, Prof. Bob Hutkins, Prof. Dan Tancredi, Prof. Dan Merenstein, and Dr. Mary Ellen Sanders along with well-known nutrition researcher, Prof. Joanne Slavin.

ILSI North America is a non-profit scientific organization whose mission is to advance food safety and nutrition science for the benefit of public health. The organization engages academic, government, and industry experts by conducting­ research projects, workshops, seminars, and publications.

 

Connecting with the ISAPP community: Continuing to advance the science of probiotics and prebiotics

By Mary Ellen Sanders PhD, executive science officer, ISAPP

On behalf of the ISAPP board of directors, I am reaching out to the ISAPP community to say we hope you are doing well and taking all the necessary steps in your local communities to remain healthy. At present, the global ISAPP community is physically distant but digitally close, and it is important for us to remain connected and strong.

ISAPP’s activities are as important as ever during this time of increased attention to health, and ISAPP is continuing to uphold its commitment to (1) stewardship, (2) advancing the science, and (3) working with stakeholders. Although our annual meeting, which some of you may have initially planned to attend, has been cancelled, other ISAPP activities are continuing or expanding as follows:

 

  • Building on an important topic for our annual meeting, ISAPP is working to develop a strategic approach to communicating the science on probiotics, prebiotics, fermented foods, synbiotics, and postbiotics.
  • The ISAPP board of directors is pleased that our founding board members, Profs. Gregor Reid and Glenn Gibson, have agreed to remain on the board until the 2021 meeting, in particular to help with long-range planning. New academic board members will also be elected, thereby expanding the board. Working together, we will bring fresh insights, strategies and global reach.
  • The board is considering how best to approach our cancelled meeting. In lieu of re-scheduling this year’s in-person meeting, we are planning to have virtual content covering some of the originally scheduled topics. Some discussion group topics will be carried over to the 2021 meeting, while others will be addressed virtually. We will communicate further on this soon.
  • Our newsletter will continue on a monthly basis.
  • Blog postings, which are aimed at either consumers or scientists, remain timely and popular – with new contributions posted on average every 2-3 weeks. Authored by board members and other experts in the field, these blogs provide a forum for opinions and observations on current issues and controversies as well as insights on global fermented foods, critical regulatory actions, and other relevant topics.
  • ISAPP filed comments on March 17 with the American Gastroenterological Association in response to their draft recommendations for probiotic use in GI conditions.
  • Spearheaded by former ISAPP IAC representative to the board, Dr. Roberta Grimaldi, ISAPP has subtitled several of the most popular ISAPP videos in different languages, including Dutch, French, Spanish, Russian, Japanese, Italian and Indonesian. The first of these should be posted by end of April.
  • The ISAPP-Students and Fellows Association has launched a blog program to provide perspectives by young scientists on issues of importance to the probiotic and prebiotic fields. They have also submitted a manuscript to Frontiers in Microbiology discussing a toolkit needed for their future in science: “Future of probiotics and prebiotics: an early career researchers’ perspective”.
  • Three consensus panels have been conducted since May of 2019. A manuscript arising from the synbiotics panel, chaired by Prof. Kelly Swanson, is in press with Nature Reviews Gastroenterology and Hepatology. The paper summarizing the consensus panel on fermented foods, chaired by Profs. Robert Hutkins and Maria Marco, is almost ready for submission to Nature Reviews Gastroenterology and Hepatology. A manuscript from the consensus panel on postbiotics, chaired by Prof. Seppo Salminen, is currently being written. All three papers are expected to provide clarity to the field with regard to definition of terms, current evidence for health benefits, and impact on stakeholders.
  • In addition to the three consensus panel papers in progress, several different ISAPP endeavors are at different stages of publication:
    • ISAPP vice president, Prof. Dan Merenstein, and executive science officer, Dr. Mary Ellen Sanders, worked with biostatistician and frequent ISAPP contributor, Prof. Dan Tancredi, to summarize evidence for clinical endpoints for probiotics, to be published in the Journal of Family Physicians. This paper, titled “Probiotics as a Tx resource in primary care”. The paper is currently in press.
    • Several ISAPP board members and other participants in a 2019 meeting discussion group recently submitted to Current Developments in Nutrition a paper titled “Dietary Recommendation on Adequate Intake of Live Microbes: A Path Forward”.
    • Marla Cunningham, the current IAC representative to the ISAPP board, has led an effort to compile results from the IAC Learning Forum from the 2019 ISAPP meeting on the topic of matrix effects impacting probiotic and prebiotic functionality. Manuscript in preparation.
    • Colin Hill and I represented ISAPP on a paper under review at Nutrients initiated by IPA-Europe titled “Criteria to qualify microorganisms as ‘probiotic’ in foods and dietary supplements”. This paper consolidates and fleshes out minimum criteria for use of the term ‘probiotic’ published by different groups, including the 2002 FAO/WHO working group, the 2014 ISAPP consensus paper on probiotics, and the 2018 ISAPP discussion group on global harmonization.
    • Glenn Gibson and Marla Cunningham are coordinating a paper titled “The future of probiotics and prebiotics in human health” as an output from their 2019 discussion group.

See here for all published ISAPP papers.

ISAPP board members, 2019 annual meeting

Messages about probiotics and COVID-19

With many conflicting and confusing health messages circulating during this global pandemic, including some criticisms of our field as well as some unsupported claims made by certain individuals and companies, ISAPP will remain an important touchstone for scientifically accurate information. Focusing on health effects is key to demonstrating probiotic and prebiotic efficacy, and we acknowledge that human studies are the ultimate measure of efficacy, but also, elucidating mechanisms of action help us understand how these interventions interface with the immune system and other mediators of health.  Currently, there is some evidence that certain probiotics/prebiotics can reduce the risk of viral infections (discussed in other blog posts here and here), but it is important to remember that they have not been studied specifically for COVID-19 prevention or treatment. This must be acknowledged when communicating with the wider community.

We greatly appreciate the continued support of our IAC members. The ISAPP Board, colleagues, and SFA will continue to chart a course forward in preparation for life after the pandemic. Our intent is to emerge from these experiences more connected and purposeful than ever. We welcome suggestions on how collectively we can endure and strengthen the science and communications that remain foundations of our field.

 

 

 

ISAPP Students and Fellows Association announce blog posting: A new way to share our work and perspectives

By Anna-Ursula Happel, president ISAPP-SFA and postdoctoral fellow at the Faculty of Health Sciences at the University of Cape Town, South Africa

Our professors keep telling us to write, write, write. Reports, papers, reviews, presentations. You can’t blame them as that’s what most of them had to do, and in a competitive environment academic output is critical. But while professors urge students to produce academic outputs, there’s a whole world of research ‘impact’ in a digital world that is beginning to matter for career advancement. To further our reach along this axis, we as the ISAPP-Students and Fellows Association (SFA) are launching a blog platform, which will be regularly updated with perspectives from our members and ideas on recent developments in the field of probiotics and prebiotics.

Our very first blog post centered on an innovative project I never thought I would hear about. Through our SFA meeting, I had heard about the Reid lab from Western University in Canada trying to find a way to prevent the decline of honey bee populations. It was a shock, since their focus for years has been women’s health. My first question to one of Dr. Reid’s students, Brendan Daisley, was: How did this come about? It turns out, the interest in how environmental toxins affect humans led to wondering how it helped really important pollinators. Not such a tangential switch as I’d thought. But what’s this got to do with the field of probiotics and my career?

Well, it shows that probiotics, as the definition states, can be applied to many hosts. It also shows that the microbiome plays a role in the health of insects as well as humans. And many of the study tools are the same – microbiota analysis, bioinformatics, immune responses, etc., yet some are totally different – using Drosophila models, counting larvae, measuring honey volumes. Read more about it here. The lesson for me: think laterally, look at how you can apply your knowledge, think of ecosystem health, and learn lots of basic skills.

Then, I thought to myself, how can research provide me with opportunities for developing leadership, initiatives and skills that are valuable for my careers. How can I gain visibility as an early-career researcher, grow my networks, improve my writing and scientific communication skills and find a platform to highlight projects that matter to me? The new blog will be helpful for all of this.

As members of the SFA, we’re very fortunate to have our voices heard; to organize our own annual meeting (well, except for 2020 when the world shut down); to be exposed to amazing scientists and ground breaking ideas – and to communicate our work, ideas and perspectives to a broad audience through our new blog. Beyond formal networking at annual meetings, the SFA blog now offers a way to stay actively connected throughout the entire year on a more informal platform with our peers, may strengthen ties within the community and even lead to collaborations and career opportunities.

See here for the ISAPP-SFA blog — bookmark it or watch for new posts on social media!

Twitter: @ISAPPSFA

 

YOGURITO –the Argentinian social program with a special yogurt

Dra. María Pía Taranto, CERELA-CONICET, Argentina and Prof. Seppo Salminen PhD, University of Turku, Finland

It is widely accepted that technologies play a central role in the processes of social change. The Argentinian experience has documented that yogurt can be a promising tool for promoting social development.  The program is called “Scholar Yogurito, the social probiotic” and the probiotic product is called “Yogurito”. This social program began with the development of a probiotic food, in the form of yogurt. This yogurt contains the probiotic strain Lactobacillus rhamnosus CRL1505, whose functional and technological characteristics are widely documented by CERELA-CONICET researchers. These researchers conducted clinical studies that demonstrated that the consumption of this probiotic product improves natural defenses and prevents respiratory and intestinal infections, the infectious events of greatest relevance in childhood. The “Yogurito Social Program” benefits some 300,000 schoolchildren in the province of Tucumán and some 50,000 in other provinces and municipalities of Argentina. This social transfer project, implemented in 2008 in the province of Tucumán, is a paradigm of interaction between the scientific sector, the manufacturing sector and the state, to improve the quality of life of highly vulnerable populations.

The social and economic implications for such translational research are significant and especially pertinent for people living in poverty, with malnutrition and exposure to environmental toxins and infectious diseases including HIV and malaria. This example of probiotic applications illustrates the power of microbes to positively impact the lives of women, men, and children, right across the food value chain. The researchers are looking for grants that would enable them to compare outcomes of schools given Yogurito to schools with no participation in the program.

 

Additional reading:

Julio Villena, Susana Salva, Martha Núñez, Josefina Corzo, René Tolaba, Julio Faedda, Graciela Font and Susana Alvarez. Probiotics for Everyone! The Novel Immunobiotic Lactobacillus rhamnosus CRL1505 and the Beginning of Social Probiotic Programs in Argentina. International Journal of Biotechnology for Wellness Industries, 2012, 1, 189-198.

Reid G, Kort R, Alvarez S, Bourdet-Sicard R, Benoit V, Cunningham M, Saulnier DM, van Hylckama Vlieg JET, Verstraelen H, Sybesma W. Expanding the reach of probiotics through social enterprises. Benef Microbes. 2018 Sep 18;9(5):707-715. doi: 10.3920/BM2018.0015.

 Senior Researcher Maria Pia Taranto and the Yogurito product

 

Maria Luz  Ovejero, a teacher at Primary School 252 Manuel Arroyo y Pinedo, explains probiotics to 4-6 year old children in Tucuman province in Argentina

Role of citizen science in research on fermented foods

By Prof. Sarah Lebeer, Universiteit Antwerpen

Spontaneous vegetable fermentations, with their rich flavors and potential health benefits, are regaining popularity among chefs and the general public. Famous Michelin star chefs, such as Belgium’s Kobe Desramaults, have implemented fermented vegetables in their recipes and offer fermented vegetable juices as non-alcoholic alternatives to wine. Serendipity was surely at play when I made contact with Kobe and his team, and had the opportunity to explore the microbial life of many of his fermented food and beverages.

Thanks to this spontaneous collaboration, I became intrigued by fermented vegetables as a promising alternative to dairy probiotic matrices. They have several benefits:

  • they are lactose-free
  • they contain no milk allergens
  • they are naturally vitamin-, antioxidant- and fiber-rich
  • they are vegan, satisfying the growing dietary trend

 

Together with prof. L. De Vuyst – a fermented food specialist from the VUB University in Brussels – we attracted a talented PhD student Sander Wuyts to study Lactobacillus’ role in the spontaneous fermentation process of carrot juices. I admit that fermented carrot juice is not the tastiest beverage I ever drank, but the fermentation process turned out to be scientifically intriguing: it appeared to be a robust, man-made microbial ecosystem dominated by lactic acid bacteria. We now often use this fermentation process in my lab as a model to study various aspects of niche-adaptation and niche-flexibility of lactic acid bacteria (LAB). And if you mix carrot juice with another fresh vegetable juice, such as cucumber, you’ll be surprised by its interesting light acidic flavor!

But perhaps the most rewarding part about our fermented-vegetables project was that we managed to carry out a Citizen Science project with the Flemish name, Ferme Pekes. You could translate it as ‘Fantastic Carrots’ 😊. Forty citizens volunteered to set up their own carrot juice fermentations at home and delivered with great enthusiasm samples of different time points. The carrots originated from their own garden, the supermarket or organic stores. Our analysis indicated that origin or organic compared to conventional product did not impact the microbial community composition. But we also could show that the LABs – first Leuconostoc then Lactobacillus – out-competed the undesirable Enterobacteriaceae after 3 to 13 days of fermentation. Longer times were needed for carrots derived from winter storage.

Our analyses (phylogenetic placement and comparative genomics, which was recently published in Applied and Environmental Microbiology) also indicated that a high LAB diversity was achieved in the different spontaneous fermentations. This is of interest if you believe it is important to let our immune system come into contact with a large and naturally diverse dose of beneficial bacteria. This idea has been promoted through the years as the hygiene hypothesis or microbial deprivation theory and aligns perfectly with the surge of interest in the health benefits of naturally fermented foods. See the recent ISAPP blog from Prof. Colin Hill, who advocates for the idea of a recommended daily allowance of consumption of live microbes.  (See also a related ISAPP blog here.) Such guidelines should be taken with precaution: the fermentations must be done properly with regard to food safety (see ISAPP blog on Making Safe Fermented Foods at Home).

Citizen Science refers to projects where citizens are actively involved in scientific studies, although it has various definitions and descriptions. In our case, it allowed us to obtain a much larger and more diverse set of samples than we could have created in the lab. Furthermore, the opportunity to directly (on e.g. workshops for adults and kids or at delivery of their samples) or indirectly (as a response to articles in the popular press) communicate with citizens helped us greatly in identifying which other research questions might be of importance for the general public. This approach is increasingly implemented in the fermented food and microbiome field. There are examples of fantastic projects such as on sourdough from Rob Dunn, Benjamin Wolfe and colleagues, the Global FoodOmics initiative and the Flemish Gut Flora project, which will also be presented by Dr. Gwen Falony at our next ISAPP meeting in Antwerp. I am not aware of a Citizen Science project in the probiotic or prebiotic area, but it might be a good idea for a joint ISAPP initiative, for science communication, the creation of richer datasets, validation/confirmation of probiotic efficacy, inspiration for future research questions, for example.

probiotics for healthy people infographic

ISAPP releases new infographic: “Probiotics for Healthy People”

November 20, 2017. Probiotics are most commonly studied with for populations with a specific condition—frequent examples include diarrhea, irritable bowel syndrome, and pouchitis. But what kind of evidence exists on probiotics for healthy people?

A new ISAPP infographic gives an overview of what we know about the use of probiotics in healthy individuals. The resource was developed by ISAPP’s Science Translation Committee and approved by  the ISAPP board of directors.

“Studying health benefits in healthy people is a challenge. But there is evidence that probiotics can provide dietary management of some digestive conditions that don’t reach the level of diagnosed disease as well as prevent of some common infectious diseases and. These, and other benefits, are of value to healthy people,” says ISAPP’s Executive Science Officer, Dr. Mary Ellen Sanders. The new infographic  emphasizes it is not necessary to take probiotics to be in good health, but they may serve as a useful addition to a healthy lifestyle.

Research investigating how probiotics can affect healthy individuals through their microbiomes is ongoing in laboratories around the world, and ISAPP continues to track the latest findings.