Fun with Fermentation

Updated: Jan 4

In today's blog post, Alex, who holds a Master's degree in Human Nutrition and is currently undertaking a PhD at the University of Oxford, will be sharing the latest science in nutritional fermentation!


Fun with fermentation:


Many of us regularly consume fermented foodstuffs without a second thought, with cheese, wine and beer as weekly household staples, some of us even managing to consume all three in a single meal. The world of fermented vegetables in particular, may not be as ubiquitous or favoured, but is underrated for several reasons. Most of us know that vegetables are good for us, as they are packed with plenty of vitamins, minerals and of course, fibre, but it is the more recent finding of a strong crosstalk between the vegetables we consume, and our brain health, that must be emphasised.


Why fermented vegetables specifically?


The process of fermentation alone is powerful in its ability to enhance the nutritive properties of food, that already exist within its constituents. Further, the process, which some may argue as just ‘leaving food to go bad’, produces microbes that travel to the gut along with the fermented food itself, and these microbes improve human health in a manner similar to that of probiotics, as they are similar in nature.


Although fermented plant products such as yoghurt, cheese and wine have their benefits, pickled vegetables such as pickled onion, pickles, and kimchi, have demonstrated anti-hypertensive and anti-obesity effects, while kombucha contains all known fermenters by far– lactic acid and acetic acid bacteria, fungi, and yeasts. Of course, you get the added benefit of both insoluble and soluble fibres, which increase the number of bacteria that produce short-chain fatty acids (SCFAs), molecules that are produced by bacteria in the large intestine that ferment soluble fibres and resistant starch, such as that in sweet potato and parsnip, and other vegetables that grow underground.


SCFAs are implicated in a whole host of health benefits, including improved energy homeostasis, appetite regulation, and sleep. Importantly, they play a critical role in gut-brain communication. Having been found in rat brains and human cerebrospinal fluid, these acids prove their ability to move from the gut, across the barrier separating the brain from the rest of the body, and into the brain.


SCFAs increase intestinal epithelium integrity and reduce inflammation, which may aid in suppressing the colon carcinogenesis. On this note of disease, since many diseases of the brain are associated with microbial imbalances in the gut, fermented foods and thus increased SCFAs are key to the balancing act of food and a healthy brain, by favouring healthy gut-brain communication. The diseases concerned are not to be downplayed, ranging from Alzheimer’s that afflicts a good percentage of the human population later in their lives, to depression and anxiety, which take their toll much earlier in life.


Perhaps all this might be more relatable in the context of this year. A review done just a few months ago by Bousquet et al found a correlation between differing rates of Covid-19 infection in different areas of the world, with consumption rates of fermented vegetables. Low death rates from this pandemic happened in East Asian and European countries, which coincidentally also consume more fermented foods, including fermented vegetables.


As a bit of a background, the binding of the SARS-CoV2 spike protein to its ACE2 receptor on cells enhances the angiotensin II receptor type 1 (AT1R) axis, which increases oxidative stress, consequently leading to endothelial damage in the lungs, as well as insulin resistance, both of which are implicated in Covid-19 as serious symptoms. Fermented vegetables such as cabbage, such as kimchi or sauerkraut, are rich in sulforaphane, which activates the powerful antioxidant Nrf2, which is a powerful neutraliser of the AT1R axis. Such finding hints at the potential of slight dietary hacks to boost your immune system!


Add some fermentation to your life!


Although extrapolation from animals to humans in order to construct dietary recommendation should always be done with caution, it does not hurt to implement more fermented foods into one’s diet routine. I hazard to say that it is actually very easy to start loving fermented foods, as they are not only tasty, but act as good palate cleansers with a magical ratio of astringency to tang. Fermented vegetables, and foods, have existed for thousands of years for a reason, with improved shelf life, relatively low cost, nutritive properties, and an appealing taste, unless you do not enjoy the umami bomb of a slice of brie washed down with sauvignon blanc. I say low cost since it is easy to make your own kimchi, pickles or kombucha at home, instead of spending your life away at Whole Foods, as fun as that can be sometimes.


There are plenty of tutorials online. If you are not as keen on the taste, and religiously remove the pickles from your burger, eating more fermented foods in general, at least a serving or two per week, will aid in growing your microbial diversity and strengthening your brain for the long-term. Who knows, just the knowledge of all the benefits kimchi can offer may persuade you to accommodate its unique flavour.


Thanks so much to Alex, and you can keep up to date and follow her own blog here! Don't forget to check out more articles if you're interested in learning more!



References

  • Bousquet, J., Anto, J., Czarlewski, W., Haahtela, T., Fonseca, S., Iaccarino, G., Blain, H., Vidal, A., Sheikh, A., Akdis, C. and Zuberbier, T., 2020. Cabbage and fermented vegetables: From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19. Allergy, 10.


  • Lavefve, L., Marasini, D. and Carbonero, F., 2018. Microbial Ecology of Fermented Vegetables and Non-Alcoholic Drinks and Current Knowledge on Their Impact on Human Health. Advances in Food and Nutrition Research, [online] (44), pp.147-185. Available at: <https://pubmed.ncbi.nlm.nih.gov/30678814/> [Accessed 14 December 2020].


  • Silva, Y., Bernardi, A. and Frozza, R., 2020. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Frontiers in Endocrinology, 11(25).



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