Researchers are studying how fermented vegetables affect inflammatory markers in women

Researchers are studying how fermented vegetables affect inflammatory markers in women

It is known that diet significantly influences human intestinal flora throughout life. For example, several studies have reported high levels of bifidobacteria in the intestines of infants receiving breast milk. In contrast, high levels of Clostridia and Bifidobacteria were observed in formula-fed infants.

Polysaccharide-rich diets are associated with increased levels of Bacteroides and Actinobacteria as well as decreased abundance of Firmicutes. In comparison, a Western diet high in animal fats and proteins and low in fiber is often associated with lower levels of Eubacterium and Bifidobacterium.

Learn: The Effects of Fermented Vegetable Consumption on Gut Microbiota Composition and Concentrations of Inflammatory Markers in Women: A Pilot and Feasibility Study.Image source: Sentelia / Shutterstock.com

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The gut microbiota is essential for the induction and activity of adaptive and innate immune responses. Dysbiosis leads to an imbalance of pathogenic and commensal bacteria in the intestine and produces microbial metabolites and antigens such as cytokines and lipopolysaccharides (LPS) that can activate intestinal macrophages.

LPS is part of the outer membrane of gram-negative bacteria and is transported in humans by the LPS-binding protein (LBP). Synthesis of LBP, an acute phase protein, reduces the biological effects of LPS. C-reactive protein (CRP) is another inflammatory marker associated with dysbiosis.

Although many nutritional approaches can alter the diversity and abundance of specific microbial taxa, further studies are needed to determine the specific health benefits of different fermented foods. For example, fermented vegetables are a source of both prebiotics and probiotics, which can help promote metabolic and gut health. However, it is not known whether it is practical for people in Western countries to consume fermented vegetables since they are not typically exposed to these foods.

A new one Plus one Study reports the effects of regular consumption of 100 grams of fermented vegetables over a period of six weeks on the expression of specific inflammatory markers and the composition of the gut microbiota.

About the study

The current study was conducted between January 2019 and October 2019 and included only women who were randomly assigned to three groups. Group A was called the fermented vegetable group, group B was called the pickled vegetable group, and group C was called the control group.

Inclusion criteria for participants included: no previous cancer diagnosis, non-smoker, not taking weight loss medications, no serious chronic illness, not taking antibiotics for at least three months before enrollment, not taking monoamine oxidase inhibitors, not regularly consuming fermented vegetables, willing to be randomly assigned to one of the three groups and willing to six Consuming fermented vegetables for weeks.

Patients with a history of uncontrolled hypertension, smoking, taking probiotics or antibiotics, younger than 18 years, older than 70 years, autoimmune diseases, and regular use of anti-inflammatory medications were excluded. Eligibility of all participants was assessed through an in-person orientation session, informed consent, and clinic visit. All study participants provided stool samples within 24 hours of their two clinic visits.

Participants in groups A and B consumed half a cup of vegetables every day for six weeks, which was equivalent to 80g of cucumbers or 100g of cabbage. In addition, they were provided seven one-cup containers of fermented cucumber/cabbage or pickled cucumber/cabbage every two weeks until the end of the study period.

Data on prescription medication use, dietary intake, and demographics were collected from all participants. All study participants also reported their gastrointestinal function, side effects, adherence to the study intervention, and the amount of vegetables consumed in cups.

Participants' dietary intake was analyzed at baseline and follow-up using a Diet History Questionnaire III (DHQ-III). Dietary variables of interest included total protein (g), carbohydrate (g), glycemic load, fiber (g), fat (g), calories (kcal), and healthy eating index (HEI). Additionally, information on weight, height, blood pressure and body composition was collected.

Blood samples were collected from all participants at two clinic visits to determine serum tumor necrosis factor-α (TNF-α), CRP, and LBP levels. Next-generation sequencing and DNA extraction were used to determine the V4 region of the 16S ribosomal ribonucleic acid (rRNA) gene of the intestinal flora.

Study results

A total of 31 participants completed the study. The participants in group C were younger than those in the other two groups.

General nutritional information was similar in terms of sodium content and macronutrients for the fermented and pickled vegetable groups. Firmicutes was the most abundant phylum in all vegetable groups, regardless of fermentation status.

The predominant genera in the fermented vegetable group included Weissella, Leuconostoc and Lactobacillus. The relatively predominant genera in the group of pickled vegetables included Paenibacillus and Bacillales.

Group A participants consumed a total of 1,237 g of fermented cucumbers and 1,609 g of fermented cabbage, while group B participants consumed 1,590 g and 1,615 g of pickled cucumbers and pickled cabbage, respectively.

The most commonly reported side effect was bloating, followed by abdominal pain. The most commonly reported stool consistency was smooth and soft.

It was observed that over 79% of participants in Group A and 89.9% in Group B showed compliance. In addition, systolic blood pressure and body fat percentage were significantly lower in participants in group C compared to the other groups.

No differences in alpha and beta diversity within or between groups were observed for the top 20 genera or phyla. Although the operational taxonomic units (OTU) for group C at baseline were lower than those of the other two groups, no differences were observed until the sixth week.

In group A, enrichment of OTU3 was observed at week six, while no such changes were observed in the other two groups. In addition, enrichment of OTU32 for group A, OTU206 for group B, and OTU163 for group C was observed at week six.

Conclusions

The current study reports that Western women can consume 0.5 g of fermented vegetables daily for six weeks without experiencing any major side effects. However, further research is needed to understand the influence of fermented vegetables on intestinal flora composition and inflammatory markers.

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Limitations of the current study include the small sample size, which consisted only of women, as well as the different age groups and body weights of the participants, which limit the generalizability of these results.

Reference:

• Galena, AE, Chai, J., Zhang, J., et al. (2022). Die Auswirkungen des Verzehrs von fermentiertem Gemüse auf die Zusammensetzung der Darmmikrobiota und die Konzentration von Entzündungsmarkern bei Frauen: Eine Pilot- und Machbarkeitsstudie. Plus eins. doi:10.1371/journal.pone.0275275.

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