Fermented Vegetables and Legumes vs. Lifestyle Diseases: Microbiota and More

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TL;DR

This narrative review summarizes current evidence on how fermented vegetables and legumes (silages) may protect against lifestyle diseases such as obesity, diabetes, and metabolic syndrome through probiotic effects, gut microbiota modulation, epigenetic changes, and increased bioavailability of antioxidants and bioactive peptides. Key mechanisms include increased butyrate production, upregulation of genes that inhibit lipogenesis (e.g., ACSL1), and the presence of ACE-inhibitory peptides and GABA, which may lower blood pressure despite the high salt content of these foods. The authors highlight critical research gaps, including the need for standardized methods to measure antioxidant potential, studies in Western populations, and clinical trials in patients with diagnosed hypertension or other lifestyle diseases.

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**Background:** Lifestyle diseases—including obesity, diabetes mellitus, metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD)—account for more than 70% of early deaths worldwide, with obesity as the leading driver. The Western diet, rich in simple sugars and saturated fats, elevates inflammatory markers such as C-reactive protein (CRP). Fermented vegetables and legumes (silages) are proposed to have pleiotropic health effects, including probiotic and antioxidant potential, that may counteract these disorders. This narrative review aimed to summarize current knowledge on the connections between fermented vegetables/legumes, their metabolism, gut microbiota, and lifestyle diseases, focusing on mechanisms such as microbiota modulation, epigenetic changes, bioactive peptides, and antioxidant activity.

**Methods:** The authors searched Scopus, ScienceDirect, and PubMed using terms including "fermented vegetables", "fermented legumes", "microbiome", "lifestyle diseases", "obesity", "metabolic syndrome", "hypercholesterolemia", "hypertension", "NAFLD", and "salt". Priority was given to articles published within the last five years. The review excluded fermented dairy, fruits, cereals, and cancer as an outcome.

**Key Results:** - **Microbiota effects:** Fermented vegetables increase lactic acid bacteria (LAB) in feces and intestinal lactic acid concentration. Kimchi consumption for eight weeks increased *Bifidobacterium longum* in obese Korean women, shifting microbiota away from the obesity-associated profile. A lower abundance of *Bacteroides* and *Prevotella* is characteristic of obesity. Higher SCFA concentrations (especially propionate) are found in obese patients versus those with BMI <30. Increased *Akkermansia muciniphila* improves glucose tolerance and reduces white adipose tissue inflammation. - **Epigenetic changes:** Butyrate upregulates acyl-CoA synthetase long-chain family member 1 (ACSL1), promoting β-oxidation and inhibiting lipogenesis. Fermented kimchi upregulated ACSL1, activating AMPK, which inhibits fatty acid biosynthesis and lowers blood pressure. - **Bioactive peptides:** Fermented legumes show ACE-inhibitory activity; pickled red bean had an IC50 of 0.63 mg protein/mL. GABA was found in pickled cucumbers at 1.32 mmol/L. Kidney beans fermented with *Lactiplantibacillus plantarum* contained 6.8–10.6 mg/g GABA. GABA from tomato puree showed higher bioavailability (AUC 115.7) than aqueous solution (AUC 59.7), with a Cmax of 184 ng/mL vs. 74.7 ng/mL. - **Antioxidant potential:** Fermentation generally increases bioavailable phenols via microbial β-glucosidase, which releases compounds from antinutrient bonds. However, results vary: red cabbage fermentation reduced anthocyanins, while pigeon pea, African yam bean, and kidney bean fermentation increased free soluble phenolic content. Vitamin C decreases during fermentation; a 2.5% NaCl concentration minimized loss (266.25 mg/100 g vs. 156.27 mg/100 g at 0.5% NaCl). - **Salt content:** Sodium content in Korean fermented vegetables ranges from 40–180 mg per serving (100–450 mg NaCl). Average daily Na intake from kimchi alone was 698 mg (1745 mg NaCl), below the 2 g Na/day WHO recommendation. Partial replacement of NaCl with KCl (30% KCl) reduces hypertension risk. Consumption of silages has not been associated with hypertension prevalence; one study found that kimchi intake for 8 weeks decreased systolic and diastolic blood pressure in overweight and obese patients.

**Clinical Implications:** Fermented vegetables and legumes represent a promising dietary strategy for preventing lifestyle diseases through multiple mechanisms, including gut microbiota modulation, increased butyrate production, inhibition of lipogenesis via ACSL1/AMPK pathways, provision of ACE-inhibitory peptides and GABA, and enhanced antioxidant bioavailability. Despite high salt content, current evidence does not link silage consumption to hypertension or kidney damage. However, critical gaps remain: most research focuses on Asian populations and products (kimchi, soy), with few studies on sauerkraut, pickled cucumbers, or fermented root vegetables common in Western diets. There is no standardized method for measuring antioxidant potential, making cross-study comparisons unreliable. Clinical trials in patients with diagnosed hypertension, obesity, or diabetes are urgently needed before specific dietary recommendations can be made. The authors call for research on optimal fermentation conditions (salt concentration, temperature, starter cultures) to maximize health benefits while minimizing sodium content.