I know you all want to rip on me for my theories about a culture's routine use of fermented foods in their diet being possibly beneficial to their immune systems nationwide, so just wanted to drop these links here for your reading pleasure. Countless other studies out there if you do a quick Google search. Perhaps I'm totally off-base here, but then again maybe not. Worth looking into IMO...
Eating fermented food can give a boost to your immune system
https://www.sciencefocus.com/news/ea...immune-system/
Metabolites of lactic acid bacteria present in fermented foods are highly potent agonists of human hydroxycarboxylic acid receptor 3
https://journals.plos.org/plosgeneti...l.pgen.1008145
Bacteria in fermented food signal the human immune system, explaining health benefits
https://www.sciencedaily.com/release...0523142201.htm
Fermented foods can add depth to your diet - Health benefits come from the live microbes that thrive in foods such as yogurt, kimchi, and sauerkraut.
https://www.health.harvard.edu/stayi...h-to-your-diet
Will a daily dose of fermented foods boost your health?
https://www.bbc.co.uk/food/articles/fermented_foods