The European Journal of Allergy and Clinical Immunology has published a blockbuster study that spotlights the role of traditionally fermented vegetables such as probiotic-rich sauerkraut in the diet as a potential mitigator of severe COVID-19 disease and mortality.
The authors of the study conceived the idea for this research because of the shocking differences in COVID-19 outcomes between various parts of the world.
What could possibly account for these disparities?
Could dietary preferences in fact play a larger role than conventional medicine has considered before?
For example, the very low death rates in Eastern Asia, Central Europe, and the Balkans have a common feature. These people groups are known for eating large quantities of probiotic-rich fermented foods on a regular basis.
In other studies to date, fermented vegetables or cabbage are associated with low overall death rates in European countries. This trend holds when COVID-19 is part of the mix.
In the chart below, the authors note that the shorter the food supply chain, the better the overall COVID outcomes. Vegetables fermented at home represent the shortest food supply chain of all.
In fact, of all the variables considered, only fermented vegetables reached statistical significance with the COVID‐19 death rate per country.
Each gram/day increase in consumption of fermented vegetables of the country reduced the mortality risk for COVID‐19 by a shocking 35.4% (1)
Fermented Foods versus COVID
The study authors note that fermentation of vegetables and other foods like dairy was introduced into the human diet during the Neolithic, aka “New Stone Age”. This period occurred some 12,000 years ago. Such foods proved essential for the survival of humankind throughout the intervening millennia.
Modern life has resulted in a drastic reduction in the consumption of fermented foods. Correspondingly, the incidence of chronic diseases has dramatically increased. Worse, the commercial, heavily marketed versions of these traditional foods are typically not fermented long enough to have the same benefit. This serves to lead consumers to falsely believe that they are consuming traditional food comparable in quality to what is made at home.
The scientists postulated that the absence of these foods negatively altered the gut microbiome. This likely resulted in the pathogenesis of various disease types. This includes allergies, asthma, rheumatoid arthritis, different types of cancer, diabetes mellitus, obesity, and cardiovascular disease. It also potentially allowed infectious diseases like SARS‐CoV‐2 (COVID-19) to rapidly spread or be more severe. (2)
Cabbage contains precursors of the organo-sulfur compound known as sulforaphane. This is the most potent natural activator of Nrf2, possibly the most active antioxidant in humans. Nrf2 blocks the AT1R axis, thereby preventing COVID-19 from binding to this receptor. When this happens, oxidative stress declines. In turn, the potential for lung and endothelial damage diminishes…two severe outcomes of COVID‐19. (3)
Fermented vegetables also contain many friendly microbes or lactobacilli, both potent Nrf2 activators.
The researchers propose that dietary manipulations such as adding fermented foods to the diet may enhance Nrf2‐associated antioxidant effects helpful in mitigating COVID‐19 severity.
For example, in central European countries where COVID death rates are low, raw and fermented cabbage is a regular feature in the diet. This is the case also in sub-Saharan Africa.
In sub‐Saharan Africa, although young age is an important factor, people commonly eat fermented foods, mainly cereal‐based foods like sorghum, millet and maize, and roots such as cassava, fruits, and vegetables. Fermented cassava products (like gari and fufu) are a major component of the diet of over 800 million people and, in some areas, these products constitute over 50% of the diet. (4)
In conclusion, the authors note that nutrition may play an integral role in the immune defense against COVID‐19. This may explain some of the differences seen in COVID‐19 between and within countries.
Since consumption of fermented foods was the only variable that reached statistical significance with the COVID‐19 death rate per country, it seems wise to introduce these traditional foods to your family’s diet if you haven’t already!
It doesn’t take much to make a huge difference either. The key is regularity, preferably daily consumption. The authors found that each gram/day increase in fermented vegetables in a particular country reduced the mortality risk for COVID‐19 by a whopping 35.4%
Thus, even a teaspoon per day (4 grams) of fermented vegetables can conceivably have a huge impact!
(1-4) Cabbage and fermented vegetables: From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID‐19