Fresher Healthier Safer
Fresher Healthier Safer
This category focuses on beneficial microorganisms, their role in health and related fermented foods.
Prebiotics, probiotics and fermented foods – they are separate and distinct, yet very much related, how so? To get the most benefit from these three, it is essential to be clear on what they are, how they are similar, related and different.
New food product development is a core element of food science and is an important way to ensure continued consumption of probiotics in food products. New products will make it easier for people to support their physical and mental health through probiotics.
Though the benefits of probiotics have been studied for almost a century, only recently have their use skyrocketed, partly owing to the current COVID-19 pandemic. Even if you are not currently consuming probiotics, chances are the thought might have crossed your mind at least once. After all, the current health food buzzword is probiotics, and so many people seem to be consuming them. Be it the ever-simple yogurt or drinks like Yakult or even probiotic capsules, the benefits advertised are many-fold, and one should incorporate them in some form in their diet, especially if experiencing gut health issues (Fig 1). However, as you begin a journey on improving your gut health, focusing on both prebiotics and probiotics can have compounded benefits when compared to your probiotic regimen alone. Well, what are prebiotics and what do they do? Prebiotics are defined as fermented short chain oligosaccharides, or fibres, that enhance the activity of our intestinal micro-flora. Simply put, prebiotics are “good food” for your intestinal bacteria and help them to produce functional metabolites, that improve our bodily health. To be functional, a prebiotic must be resistant to colonic digestion by the host while undergoing fermentation by the intestinal microbiota. Applying this definition, there are several digestive fibers which can be utilised as prebiotics. Generally, these include resistant starch, fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), and several non-starch polysaccharides. These undergo fermentation and ultimately get released as short chain fatty acids or SCFAs, which aid in several physiological functions of our body. Now that we know their benefit, one can obtain their prebiotics naturally, from several foods, including chicory root, artichokes, garlic, onion, and cereals such as wheat, barley and millet (Fig 2). If you already have a diet rich in fiber, you can start adding probiotic foods, and vice versa if you already consume probiotics. Either way, it is imperative to modify your diet to add more fiber to have a healthy gut. You will have small issues like bloating, flatulence, or other disorders when you practice a poor diet – constituting less fibre intake – and if continued long term, it can become chronic and may even lead to inflammatory diseases like inflammatory bowel disease (IBD), colitis, persistent diarrhea and other gastrointestinal conditions. BENEFITS It has been demonstrated that our gut is connected to our brain through a network of millions of neurons, and bidirectional signals between the brain and our gut through the vagus nerve can alter the GI tract’s sensory and motor function whilst impacting our brain functions too. Our enteric nervous system (ENS) regulates our gut function through peristalsis, absorption, and secretion, while our autonomic nervous system (ANS) does the same using the central nervous system (CNS), by controlling digestion, bile secretion, mucus levels and more. As mentioned earlier, SCFAs produced from the fermentation of prebiotics are absorbed into our blood circulation, and reach various tissues, including our brain where they play a pivotal role in regulating our neurological functions. Several mice model studies have confirmed that the SCFAs play a role in ENS homeostasis, stress alleviation, and promote regularity of our neural systems (Everard et al, 2011; Savignac et al, 2015; Burokas et al, 2017). Additionally, some prebiotics are known to increase our native gut microbiome proliferation, promote anti-inflammation, and reducing anxiety-like behaviors signaling a direct effect on our brain function trough the gut-brain axis. However, it’s not just the nervous system that is the point of action for the prebiotics. As you build up your fiber intake, the accretion of the chewing time in the oral cavity can promote saliva and gastric acid production, which also contributes towards higher satiety (Parnell et al, 2006). This also affects our insulin, and ghrelin (hunger hormones) secretions, eventually regulating our food intake and promoting satiation (van der beek et al, 2018). However, the most interesting claim for prebiotic intake is the supposed health implications on our gut immunity. One may be confused about the term “gut immunity”, and rightly so. Though it is well known that our immune system is composed of several barriers, our gut encounters the majority of antigens, and any immunogenic compromise can have adverse health effects almost immediately. So, it is no surprise that the major player in our immune system is located in our gastrointestinal tract – gut associated lymphoid tissue (GALT). GALT induces immune reaction by activating T cells, dendritic cells, macrophages, and mast cells in response to pathogenic entry and prebiotics can enhance our GALT’s action. SCFAs are known to reduce the occurrence of colon cancer, colitis, and may also inhibit colonization of pathogenic bacteria to our epithelial lining through anti-inflammatory pathways (Komiyama et al, 2011; Rivera-Huerta et al, 2017; Rani et al, 2019). Among other functions, SCFAs also act as signaling factors and increase the production of regulatory T cells, improving our gut immunity (Freitas et al, 2014). SCFAs produced by our gut microbiome also increase calcium bioavailability, thereby increasing our bone density and improving iron absorption. Epidemiological research has also suggested a link between a low prebiotic diet and cardiovascular diseases (Kochar et al, 2007; Tang et al, 2019). SCFAs alter lipid metabolism, and possibly lower your risk for heart diseases, by reducing the LDL cholesterol serum concentrations. Overall, the promising benefits of prebiotics promote them as a powerful tool for altering your microbial composition and to strengthen your immunity. REFERENCES Burokas, Aurelijus, Arboleya, Silvia, Moloney, Rachel D, Peterson, Veronica L, Murphy, Kiera, Clarke, Gerard, Stanton, Catherine, Dinan, Timothy G, & Cryan, John F. (2017). Targeting the Microbiota-Gut-Brain Axis: Prebiotics Have Anxiolytic and Antidepressant-like Effects and Reverse the Impact of Chronic Stress in Mice. Biological Psychiatry (1969), 82(7), 472–487. https://doi.org/10.1016/j.biopsych.2016.12.031 Everard, A, Derrien, M.M.N, Possemiers, S, Vos, de, W.M, Delzenne, N.M, Schrenzel, J, & Cani, P.D. (2011). Responses of gut microbiota and glucose and lipid metabolism to prebiotics in genetic obese and diet-induced leptin-resistant mice. Diabetes (New York, N.Y.), 60(11), 2775–2786. https://doi.org/10.2337/db11-0227 Freitas Gomidesl, A. F., de Paula, S. O., Goncalves, R. V., de Oliveira, L. L., Fortes Ferreira, C. L.
The text of this blog article was originally written by Amy Tsang, a 3rd-year food technology student of mine at RMIT University in 2009. I have provided some slight updates/changes/revisions. While probiotics now exist (for example, Bacillus coagulans) that are able to withstand pasteurisation and high pressure processing, there’s no doubt of the ongoing importance of the issue of viability of probiotics, given adequate amounts of the organisms reaching the appropriate place in the gastrointestinal tract is a requisite for their success, and the multitude of factors that can negatively impact probiotic survival during manufacture, in food and during gastrointestinal passage, as noted in the image above. Probiotics continue to attracted much interest from consumers; who are concerned with their personal diet and lifestyle. These consumers expect that the functional foods they consume will exert clear health benefits for their digestive system; especially in Europe where gut health is a key component for the benefits provided by functional foods (Mattila-Sandholm et. al, 2002). Future research into probiotics may also help to alleviate many health issues such as allergies or even particular types of cancers. Currently there are many studies focused on probiotic survival through the gastrointestinal environment. Misconceptions about probiotics need to be defended when placed under scrutiny (Gorbach, 2002). To counter misconceptions of probiotics, detailed research and human/clinical studies need to be conducted by scientists to prove to consumers that probiotics have health promoting properties. In addition, consumer education is also important; if probiotics were to become a part of the daily diet; appropriate scientific facts and information should be made readily available for consumers. Without consumer confidence, the probiotic industry would not prosper. There are several major issues that need to be addressed before developing new probiotic products or re-formulating products for consumption. The viability and stability of probiotics and maintaining an acceptable number of viable cells above food standard requirements throughout the whole shelf life of the product and ensuring specific probiotic strains are chosen that can withstand the gastrointestinal stresses present in that environment; these have all been major challenges for the food industry (Mattila-Sandholm et. al, 2002). These requirements highlight the need for innovative solutions such as new technological advancements; however maintenance of low production costs will also be high on the agenda as the solutions need to be financially viable for food manufacturers and consumers alike. Yoghurt, a popular dairy product with probiotic health benefits, has established the foundations for further research into other potential probiotic functional foods such as; probiotic drinks, non dairy beverages; vegetable and fruit juices, desserts for vegetarians, baby foods, and cereal based products (Mattila-Sandholm et. al, 2002; Heenan, 2004 et. al; Prado et. al, 2008; Lee & Salminen, 1995). Various ideas towards the method of benefit offered by probiotics have been hypothesised. Although these significant methods have not been completely established, the possibilities include; rivalry for nutrients, secretion of microbial substances, blocking of adhesion sites, decrease in virulence, blocking of toxin receptor sites, immune stimulation and suppression of toxin production (Fooks et. al, 1999). The competition for nutrients is quite a significant factor for any bacteria thriving in the gastrointestinal tract. Various bacterial species are quite specific in their nutritional requirements and so one particular population may deplete nutrients at the expense of another species (Fooks et. al, 1999); thus if probiotics were used in this circumstance it would be highly beneficial to the gut flora, where health promoting bacteria may predominate. In general terms, probiotic foods and supplements are expected to restore the balance in the gut; given there are sufficient numbers, which is generally 106 cfu/g (Elahi et.al, 2008; Lee & Salminen, 1996). Probiotic effectiveness can be further enhanced with the inclusion of probiotics for a symbiotic effect. According to (Fooks et. al, 1999) this combination of one probiotic with another probiotic can enhance the survival of probiotic bacteria overall. To further highlight the importance of probiotic bacterial survival, there are also other issues to consider. Although probiotic bacteria in food products may be able to survive the initial fermentation, production process; the storage and the gastrointestinal tract are also of great concern, probiotic bacteria may be susceptible to extreme and harsh environments. As discussed by (Lacroix & Yildirim, 2007) the storage conditions can have an impact on probiotic bacteria such as oxygen stress, competition with other organisms, variability in temperature and moisture content, given that the probiotic bacteria do survive during storage they are then exposed to the gastrointestinal tract. Furthermore, the gastrointestinal tract will have extreme acidic conditions present in the stomach and enzyme activity will be present, thus the composition of the environment may not favour the probiotic bacteria and presence of bile salts in the small intestine may inhibit the growth of the probiotic bacteria ingested (Lacroix & Yildirim, 2007). These are typical stresses which probiotic bacteria may be subjected to, therefore probiotic bacteria chosen for products should be those that can adapt to extreme conditions and changing environments (Lacroix & Yildirim, 2007). Therefore due to such conditions, it is not always likely that sufficient numbers of probiotic bacteria will reach the appropriate gut location to exert their beneficial health effects. A research project was conducted by (Gibson & Brostoff, 2005 – apologies, citation details cannot be found!) to test commercially available supplements that contained strains of probiotic bacteria and their survival in the gastrointestinal environment. Their results demonstrated that Lactobacillus spp. were resistant to the gastric environment, however they were sensitive to the upper intestinal content, on the contrary Bifidobacterium spp. displayed sensitivity to the stomach environment but were able to survive well in the upper intestine. This study highlighted the significance of different probiotic species and their diverse capacity to survive within the intestinal environment. References Elahi, S., Farnell, P., Thurlow, K. J., Scotti, C., Varnam, A. H., 2008, ‘Referee analysis of probiotic food supplements’. Food Control, vol 19, pp. 925-929. Fooks, L. J., Fuller, R., Gibson, G. R., 1999, ‘Prebiotics, probiotics and human gut microbiology’. International
Probiotics are increasingly recognised as being able to confer a myriad of health benefits, supporting by evidence-based science. One of these is mental health, a fascinating area where natural approaches to maintaining/restoring one’s mental health are possible.
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