Fermented foods often contain beneficial bacteria. But does this affect the gut microbiota?
Still little scientific research into fermented foods
Although fermented foods are generally considered healthy and good for the microbiota, historically there has been little scientific research actually measuring the effect of fermented foods on the microbiota. But a new study involving 6,811 participants from the American Gut Project has addressed the question of whether there is a difference between the microbiota of people who eat fermented food regularly and that of people who do so rarely or not at all. Additionally, for four weeks the study followed a subgroup of 115 people who consumed fermented foods regularly. This constituted an examination of the influence of fermented foods on the composition and functionality of the gut microbiota.
Comparison of consumers with non-consumers
The 6,811 participants were divided into groups of either consumers if they ate fermented plant foods (kimchi, kombucha, etc.) at least once a week or non-consumers. When the groups’ gut microbiota were compared, both groups were shown to have the same number of the various types of bacteria in their intestines. However, between the two groups, the composition of the gut microbiota appear to differ subtly, but significantly.
Research into consumers’ microbiota
Subsequent examination was performed on the composition of the microbiota of the 115 people who consumed fermented foods regularly. The subjects in this group were shown to carry specific bacteria associated with fermented foods, such as various types of lactobacilli. Also found were metabolites that are associated with good health. Metabolites are substances produced in the intestines by bacteria and therefore say something about the functioning of the gut microbiota. The most notable metabolites were fatty acids, namely conjugated linoleic acid. This acid, which almost certainly comes from bacteria, is associated with health benefits such as protection against heart and vascular diseases.
Minor but clear effect on microbiota
On the whole, the researchers found modest, but clear indications that fermented foods cause subtle shifts in the microbiota. Considering the increased interest in fermented foods, the researchers think it clearly worthwhile to further study their influence on health.
Taylor, B C., F Lejzerowicz, M Poirel, J P. Shaffer, L Jiang, A Aksenov and R Knight. "Consumption of fermented foods is associated with systematic differences in the gut microbiome and metabolome." Msystems 5 (2020): e00901-19.