Fermented vegetables: good reasons to include them in your diet
What do sauerkraut, kombucha, sourdough bread and kefir all have in common1? They are fermented foods, and scientists are taking increasing interest in their health benefits. An American study2 has revealed that eating a portion of fermented vegetables daily is beneficial for gut microbiota after just 6 weeks.
About this article
According to the official scientific definition, fermented foods are “foods made through desired microbial growth and enzymatic conversions of food components”3. More simply, they are processed using microorganisms such as lactobacilli (“lacto-fermented” foods) and other species of bacteria, filamentous fungi or yeast3. These foods provide beneficial microorganisms, vitamins, prebiotics and bioactive compounds of plant origin that balance gut microbiota. According to various studies3,4, they are also thought to have digestive and metabolic benefits.
5,000 fermented foods Over 5,000 fermented foods and beverages are listed worldwide, representing between 5 and 40% of the human diet.
Inviting fermentation onto our plates
So why not include fermented foods in our daily diet to improve our health? A team of researchers decided to evaluate the feasibility and effects of consuming fermented vegetables (cabbage and pickles) for 6 weeks on the composition of the gut microbiota of 31 women. The participants were divided into three groups: the first consumed 100 g of fermented vegetables per day, the second 100 g of the same vegetables in brine (not fermented but preserved by acidification3) per day, and the third group, a control group, were asked to continue eating as usual. Stool samples were collected at the beginning and end of the study to analyze the gut microbiota.
More beneficial bacteria in gut microbiota
Results: The gut microbiota of the women who consumed fermented vegetables was richer in Faecalibacterium prausnitzii, which according to studies are abundant in healthy people and protect against inflammation, oxidative stress and pathogenic germs. There were also fewer Ruminococcus torques bacteria, thought to promote inflammation and metabolic problems. Overall, their microbiota had more diverse microbial communities, beneficial for its balance.
Easing digestive transit with fermented cabbage!
In terms of digestion, the women consuming fermented vegetables experienced more bloating than those not consuming vegetables, which was expected because of the cabbage, a well-known source of natural gas! However, they also experienced less diarrhea than those consuming brined vegetables, suggesting that fermenting vegetables improves stool consistency, and less stomach upset than the other two groups. Finally, in terms of regularity, while 70 to 90% of the women in the “cabbage-pickles” groups stuck to their diet, some found it tough on reaching the end of the 6 weeks...
This pilot study suggests that consuming 100 g of fermented vegetables daily for 6 weeks is feasible and beneficial for gut microbiota: more work is now necessary to determine whether fermented vegetables could effectively fight dysbiosis. Its authors suggest offering participants a wider variety of vegetables to reduce the side effects and boredom.
1. ISAPP. How are probiotic foods and fermented foods different? 2020 : https://isappscience.org/wp-content/uploads/2021/01/ProbioticsvsFermentedFoods.pdf
2. Galena AE, Chai J, Zhang J, et al. The effects of fermented vegetable consumption on the composition of the intestinal microbiota and levels of inflammatory markers in women: A pilot and feasibility study. PLoS One. 2022;17(10):e0275275
3. Marco ML, Sanders ME, Gänzle M, et al. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nat Rev Gastroenterol Hepatol. 2021;18(3):196-208
4. ISAPP. Fermented Foods : https://isappscience.org/for-consumers/learn/fermented-foods/