Fermented foods: an avenue to supporting gut microbiome diversity

Fermented foods are defined as “food made through desired microbial growth and enzymatic conversions of food components” (Marco et al., 2021). There are several reasons that food fermentation is performed; as a method of food preservation, to reduce risk of food contamination with pathogenic microorganisms, or to enhance the taste and textures of some foods (Dimidi et al., 2019). As a result, there are many potential indications and benefits to performing food fermentation.

The surge in interest in fermented foods is due to the growing interest in the role of the gut microbiome in health and the health promoting potential of foods that have undergone the fermentation process. These potential benefits are attributed to the presence of probiotic bacteria, such as lactic acid bacteria, and in turn, how these microbes can impact the overall composition of the gut microbiome (Sanlier et al., 2019). Beneficial bacteria such as Lactobacillus, Bifidobacterium and Saccharomyces species are most commonly present in fermented food products (Sharma et al., 2020), and their abundance is associated with an increase in microbial diversity – a state that correlates with positive health outcomes (Valdes et al., 2018).

Many types of foods can be fermented, from dairy products to vegetables, as well as beverages, such as green and black tea. Here are some examples of fermented food and their benefits –

Types of fermented foods

Kefir

Kefir is a cultured dairy product, typically made through the fermentation of milk by kefir grains. It contains an abundance of microbes, with large concentrations of Lactobacillus Kefiri, which studies show can induce positive changes to gut microbiome composition, promoting a balanced microbial community (Carasi et al., 2015; Veiga et al., 2014).

Kombucha

Kombucha is a drink made by fermenting sweetened black or green tea with a symbiotic culture of bacteria and yeast. Rich in beneficial bacteria such as Lactobacillus and Saccharomyces, regular consumption of Kombucha could assist in the removal of pathogenic microbes (Chong et al., 2023). Kombucha is also rich in polyphenols, which could help to reduce oxidative stress and inflammation of the gut lining (Chong et al.,2023)

Kimchi

Kimchi is a traditional Korean dish, made from fermented vegetables such as cabbage and radishes, with added spices (Jang et al., 2015). Kimchi contains beneficial lactic acid-producing bacteria and is often rich in various vitamins, such as vitamins A and C, all of which have been shown to support a strong immune system (Mathur et al., 2020).

Sauerkraut

Sauerkraut is a fermented cabbage dish containing beneficial bacteria such as Lactobacillus and Leuconostoc (Satora et al., 2021; Jonanningsmeier et al., 2007). Similar to the other fermented foods, Sauerkraut can help to enhance gut microbial diversity, playing a vital role in the promotion of overall gastrointestinal health (Shah et al., 2023). Certain Lactobacillus species isolated from sauerkraut have demonstrated a probiotic effect and antimicrobial activity against pathogens (Ge et al., 2009).

Conclusion

Fermented foods, such as kefir, kombucha, kimchi and sauerkraut, are great additions to the diet and can offer a wealth of benefits to support gut health and a balanced gut microbiome. Whilst there is currently no dietary guidance for the inclusion of fermented foods, consuming them on a weekly basis could be a step to incorporate beneficial probiotics into the diet.

References

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