Fermented kimchi may help combat obesity by regulating gut microbiota

Study highlights kimchi’s role in modulating gut microbiota, increasing beneficial bacteria, and reducing body fat mass in overweight individuals.

​​​​​​​Study: Effects of kimchi consumption on body fat and intestinal microbiota in overweight participants: A randomized, double-blind, placebo-controlled, single-center clinical trial. Image Credit: gontabunta/Shutterstock.com

In a recent study published in the Journal of Functional Foods, a group of researchers evaluated the effects of daily kimchi consumption on body fat reduction and gut microbiota composition in overweight individuals.

Background

Obesity, linked to conditions like diabetes, heart disease, and cancer, arises from factors such as genetics, diet, and gut microbiome composition. Diet plays a key role, with kimchi, a fermented Korean food rich in probiotics, showing promise in obesity management.

Kimchi’s contains cabbage, garlic, ginger, and red pepper, which are metabolized into bioactive compounds during fermentation, which improve gut health, regulate metabolism, and increase beneficial gut bacteria like Akkermansia muciniphila.

Animal and clinical studies demonstrate kimchi's potential in reducing body fat and restoring gut microbiota balance. Further research is needed to confirm these effects and mechanisms in diverse human populations.

About the study

Ninety adults aged 20-65 years with a body mass index (BMI) of 23-30 kg/m² were recruited for this study through advertisements and email promotions.

Participants agreed not to consume kimchi during the trial. Exclusion criteria included recent severe cerebrovascular or heart diseases, malignant tumors, uncontrolled hypertension or diabetes, significant kidney or liver dysfunction, severe gastrointestinal symptoms, or recent use of medications affecting weight.

Participants were randomly assigned to three groups (placebo, spontaneously fermented kimchi (S-K), or starter-fermented kimchi powder with Leuconostoc mesenteroides KCKM0828 (LMS-K)), with each group receiving a unique screening code to ensure blindness. Each group consumed 3000 mg daily of their respective intervention in capsule form for 12 weeks.

The kimchi powders were prepared in a controlled laboratory. Ingredients included cabbage, red pepper, garlic, ginger, radish, and onion, with LMS-K as a starter culture. The powders underwent quality assurance for fermentation (pH verification) and were encapsulated with consistent ingredient ratios.

Body composition was measured using dual X-ray absorptiometry (DEXA), and blood samples were analyzed for metabolic markers. Fecal samples were collected for gut microbiome sequencing. Safety, dietary intake, and physical activity were monitored throughout the study.

Statistical analyses were conducted using appropriate methods to assess the impact of interventions on anthropometric and microbiome-related outcomes.

Study results

To assess the LAB composition in S-K and LMS-K, bacterial 16S ribosomal Ribonucleic Acid (rRNA) gene amplicons were sequenced using Illumina technology. Latilactobacillus sakei (L. sakei) (48.14%) and Leuconostoc carnosum (20.58%) dominated in S-K, whereas Leuconostoc mesenteroides (39.93%) and L. sakei (28.06%) were predominant in LMS-K.

Metabolite analysis via Liquid Chromatography-Mass Spectrometry (LC-MS) revealed higher concentrations of caffeine, ferulate, and p-coumarate in S-K, while LMS-K exhibited elevated levels of caffeate and p-coumarate.

Ninety participants aged 20-65 years with BMIs between 23-30 kg/m² were enrolled, agreeing to avoid kimchi throughout the trial. Randomly assigned to placebo, S-K, or LMS-K groups, 83 completed the study.

Compliance rates exceeded 94% across all groups, with no significant intergroup differences. Baseline characteristics, including age, BMI, and waist-to-hip ratio, showed no significant differences except for hip circumference.

Anthropometric analysis revealed significant increases in body fat mass and percentage in the placebo group after 12 weeks. In contrast, the S-K and LMS-K groups demonstrated significant reductions in body fat mass compared to placebo, even after adjusting for covariates.

LMS-K also showed a substantial increase in fat-free mass. Body weight and BMI significantly increased in the placebo group but remained stable in both kimchi groups.

Biochemical markers showed significant differences in baseline triglyceride (TG) levels but no disparities in other markers. After 12 weeks, TG levels increased in the placebo group, while the LMS-K group showed a significant reduction compared to placebo.

LMS-K also improved Low-Density Lipoprotein (LDL) and High-Density Lipoprotein (HDL) cholesterol levels, though some significance was lost after covariate adjustments.

Hemoglobin A1c (HbA1c) levels significantly decreased in both kimchi groups, while fasting glucose was only reduced in the placebo group. No significant changes were observed in free fatty acids, insulin, or inflammatory markers.

Gut microbiome analysis demonstrated no significant changes in alpha or beta diversity across groups. However, both kimchi groups showed increased Akkermansia muciniphila, a beneficial bacterium associated with metabolic health.

Linear Discriminant Analysis Effect Size (LEfSe) analysis highlighted reduced levels of Proteobacteria in S-K and LMS-K groups, alongside other favorable shifts in microbial composition.

Dietary intake and physical activity levels remained consistent across groups, with no significant changes before or after the intervention. The trial reported no serious adverse events, confirming the safety of kimchi consumption in all groups.

Conclusions

To summarize, this study demonstrated that kimchi consumption significantly reduces body fat and improves obesity-related metabolic indicators in overweight individuals. S-K and LMS-K induced reductions in body fat mass, with LMS-K showing additional benefits, such as decreased LDL and TG levels and increased HDL levels.

Kimchi’s anti-obesity effects appear to involve probiotics, including Akkermansia muciniphila, which increased in abundance with kimchi intake.

Changes in the gut microbiota, including reductions in Proteobacteria and enrichment of beneficial bacteria like Megasphaera, suggest that kimchi fermentation influences microbial composition. Phytochemicals in kimchi may act as prebiotics, enhancing probiotic growth and contributing to metabolic health.