Fermented foods, such as sauerkraut and kombucha, have become popular for health reasons. I have made my own sauerkraut in the past and have recently made the tasty, fermented Korean side dish, kimchi. I did it not only for the taste but also for the hope that the bacteria responsible for the fermentation of the cabbage — lactic acid bacteria (LAB) — would contribute to the diversity of my gut microbiota.
As a research scientist in the field of bacterial pathogenesis, this made sense to me. Now that I have started blogging about health and fitness and have been writing more in depth articles about health related topics, I started wondering what research has been done on the health benefits of fermented foods. Can the bacteria in fermented foods even survive the harsh conditions of the human gastrointestinal (GI) tract, particularly the stomach?
I was amazed to learn that the fermentation of food has been used by humans for thousands of years as a way to preserve foods, and that the health benefits go beyond their microorganisms (don’t worry, citations are provided below). The fermentation process enhances the nutritional quality of food by contributing beneficial compounds such as vitamins, and by increasing the bioavailability of minerals. Probiotics, including those found in kimchi, have a range of positive effects on health, including the improvement of various intestinal inflammatory conditions, positive impacts on the immune system and even weight loss, and can alter the composition of the gut microbiome.
However, these effects mostly depend on whether the bacteria actually make it in sufficient numbers to the colon. And let me tell you, the journey to the colon is one harsh and dangerous ride!