On Sunday 20 October 2019, I had the opportunity to present this talk twice, at the 2nd annual VegoFest in Melbourne, a celebration of all things ‘vego’, organised by the Vegetarian and Cultural Association Incorporated. What follows are the slides I used and (almost) a transcript of what I said.
Slide 1 – G’day everyone, I’m Philip, an independent food microbiologist at my own start-up institute, Food Microbiology Academy. Today I want to take you through what is one of the hottest topics in food microbiology at the moment, probiotics and gut health with this presentation titled “A natural way to get your dose of good bacteria”.
Slide 2 – Before we actually get into the presentation proper, I want to give you a definition of “natural”, which will be relevant later on in the presentation, since the title of this talk refers to “natural”. So in the food context, natural refers to a food “having had a minimum of processing or preservative treatment” – just keep this definition in the back of your mind as we progress through the talk.
Slide 3 – Now, to start off with, I want to let you know, or remind you that microorganisms are indeed everywhere. They have colonised every conceivable habitat and environmental niche on the planet – from really hot, to really cold, dark and high pressure environments. Microorganisms are ubiquitous to the extent that if we can’t find them, then our current technology is probably not good enough to detect them!
Slide 4 – Not only are they everywhere in an environmental context, but everywhere includes being on and in us too. This image is to give you an indication that yes, microorganisms are living, growing and indeed thriving on and in our bodies, even in the harshest environments like the dry and salty skin and the highly acidic and low pH environment of the stomach.
Slide 5 – This slide is to give you an indication of some of the so-called good guys and bad guys of the bacterial world, some of which you may have heard about. Good bacteria include various species of Lactobacillus, Streptococcus thermophilus and Bifidobacterium longum. Some of the Bacteria which always spell trouble are Salmonella typhi, most species of Streptococcus apart from Streptococcus thermophilus and Helicobacter pylori.
Slide 6 – What we have here are some of the general benefits afforded by good gut Bacteria. Starting at the top right – i) they produce various compounds which assist in digesting food, ii) some of them produce vitamins which are essential in human nutrition, iii) due to the location they reside and their numbers, they exert a protective effect on the epithelial lining of the gut, iv) modulation of the immune system is another important role they play in host non-specific defences and v) they employ various strategies to ward off pathogenic Bacteria, which we’ll cover off in the next slide.
Slide 7 – Here we have various means employed by your resident gut Bacteria to resist colonisation by invading pathogenic Bacteria. Firstly number one, on the left hand side is “Adhesion exclusion” – which means that the pathogens need to adhere to the cells lining the host’s gut in order to exert their disease potential. However, due to competition for space and adhesion sites which the resident microbiome, the pathogens invariably miss out, and hence are excluded from gaining a ‘foothold’. Numbers two and three refers to the fact that the pathogenic Bacteria, like all Bacteria and indeed all living organisms refer adequate nutrition. Limitation on carbon sources, which are used for energy and micronutrients, by the good Bacteria essentially starve the invading Bacteria of the nutrients they need to thrive, grow and even survive. If this isn’t enough, your resident good Bacteria produce antimicrobial substances and toxins which directly attack ad destroy the ‘bad guys’. While your gut microbiota is employing all these strategies to ward off the invaders and prevent disease, the pathogens have a host of virulence factors they are expressing to combat everything ‘being thrown at them’. Basically, there’s a ‘war’ going on in your gut, the good Bacteria of your gut versus the invading pathogenic Bacteria. If the ‘good guys’ win, you stay healthy, but if the ‘bad guys’ win, then you get sick – it’s as simple as that!
Slide 8 – So, we know probiotic Bacteria are good and we need to look after and replenish our gut microbiome, but how? Well, there’s basically two ways – probiotic supplements, so tablets or pills containing probiotics or the alternative, the more natural way, is to consume fermented foods containing probiotics, such as these yum fermented vegetables. Something to remember – not all fermented foods contain probiotics and not all fermented foods that are meant to contain probiotics, actually do. For example, if sauerkraut has been heat treated after fermentation, then the probiotic Bacteria are going to be all but killed off. Thus, the best option is actually to make your own fermented foods.
Slide 9 – Here we have a range of fermented foods displayed, but like we said in the previous slide, not all of them are actually probiotic foods. Tempeh, kombucha and soy sauce are fermented foods, but do not contain probiotics – even chocolate manufacture includes a fermentation step, but is not considered a probiotic food. Sauerkraut, kimchi and natto are fantastic vegan probiotic fermented foods while kefir is an excellent probiotic dairy drink.
Slide 10 – In this slide I want to concentrate on two fermented cabbage products, Korean kimchi and German sauerkraut. Both are amongst the healthiest fermented probiotic foods to include in your diet. They can certainly be considered a physiologically functional food due to all these added benefits they offer – both promote immune system function while interestingly, probiotic lactobacilli starter cultures from kimchi have demonstrated anti-obesity effects when used as a dietary supplement.
Slide 11 – So, to sum up – if you take antibiotics, lead a stressful lifestyle, including getting insufficient sleep and are careless with food safety, then you are supporting and encouraging the growth of pathogenic Bacteria. On the other hand, if you include fermented foods or probiotic supplements in your diet and your diet is healthy, which means, based on fruit and vegetables, then you are providing the best conditions for growth or ‘friendly Bacteria.
I’ve included a list below of some books on Amazon related to this topic: