To the Editor,
The fermentation process, born as a preservation method in the Neolithic
age, enabled humans to eat not-so-fresh food and to survive.1 Fermented foods are “foods or beverages made via
controlled microbial growth (including lactic acid bacteria (LAB)) and
enzymatic conversions of food components.” 2 Not all
fermented foods contain live cultures, as some undergo further
processing after fermentation: pasteurization, smoking, baking, or
filtration. These processes kill or remove the live microorganisms in
foods such as soy sauces, bread, most beers and wines as well as
chocolate. Live cultures can be found in fermented vegetables and
fermented milk (fermented sour milk, yoghurt, probiotics, …). The
westernized diet is lacking many traditional fermented foods.3
The gut microbiota has an inter-individual variability due to genetic
predisposition and diet 3. Some foods like cabbage can
be fermented by the gut microbiota. 4 The westernized
diet has been associated with changes in the gut microbiome.5
In this Rostrum, we consider loss of food fermentation either as a
reduction of fermented food consumption in the diet or as a change in
the microbiome leading to a reduction of fermentation of foods in the
gut. This paper is based on the hypothesis that diet may partly explain
differences in COVID-19 death rates within and between countries.6