In ancient societies, fermentation was a very common food preservation method. And, while they may not have understood the mechanisms involved, by eating fermented foods, their overall health flourished — principally, their intestinal health. Today, we have a much more comprehensive understanding of the human microbiome, and its influence on health. We also now know that the best ways to improve gut health are to consume fermented foods on a regular basis and avoid sugar and processed foods.
About 80 percent of your immune system is in your gut. When your intestinal flora is skewed toward more sugar-loving pathogenic microbes, health problems of all kinds are more prevalent, from obesity and diabetes39,40 to allergies and autoimmune diseases. The fiber and wide variety of beneficial bacteria (probiotics) found in traditionally fermented and cultured foods help protect against disease by improving your microbiome, and also help chelate harmful toxins and heavy metals from your system.
Nearly all organic plant matter (and even the dust covering the soil) contains lacto-fermenting bacteria called Lactobacilli, or Lactobacillus acidophilus. As Lactobacilli start multiplying in the fermentation process, they produce lactic acid. When lactic acid is produced, it helps preserve the food. Another benefit is that fermentation makes nutrients more bioavailable.
It also provides instant energy. Several studies indicate the many amazing benefits fermentation brings to your gut health. For instance, one week after sauerkraut begins fermenting, the vitamin C content rises to around six times higher than in the same amount of plain cabbage.41
Another fermentation advantage is vitamin K2, which works in tandem with and provides many of the same benefits as vitamin D. Certain cheeses, homemade yogurt, kefir and natto (fermented soy) are good sources of vitamin K2. There are only certain strains of bacteria that make K2, so not all fermented foods will contain it. Most commercial yogurts are virtually devoid of vitamin K2, and while certain types of cheeses, such as Gouda, Brie and Edam are high in K2, others are not.
It really depends on the specific bacteria present during the fermentation. When fermenting your own foods at home, using a special starter culture designed with bacterial strains that produce vitamin K2 will ensure a vitamin-K2-rich result.