# The Role of Fermented Vegetables as a Sustainable and Health-Promoting Nutritional Resource
## 1 Introduction  
A variety of biological, genetic, physiological, psychological, and sociocultural factors shape the food choices of the population [1]. Lately, there has been a growing interest worldwide in the potential benefits of plant-based diets [2, 3]. The increasing global burden of morbidity and mortality from chronic diseases related to low diet quality and excessive calorie intake, combined with the unsustainable depletion of vital planetary resources by current food production systems, threatens future food security, highlighting the urgent need to transition towards high-quality plant-based diets as a viable solution to mitigate economic, health, and environmental challenges [4, 5, 6]. Dietary patterns are important determinants of health, as they may exert effects through several mechanisms, including inflammation, oxidative stress, tryptophan metabolism, epigenetics, central nervous system (CNS) and hypothalamic-pituitary-adrenal functions, mitochondria, and the gut microbiome (GM) [7, 8]. In addition, epidemiological studies have reported the involvement of diets in the development of psychological and psychiatric disorders [7, 9, 10], as well as their application as potential therapeutic tools for these mental conditions [11, 12]. Variations in a healthy GM depend on age, lifestyle, ethnicity, and eating habits [13, 14]. Human-microbial interdependence is driven by theco-evolution of the human immune system and the GM's adaptation to available nutrient substrates [15]. Diets supply specific nutrients for the proliferation kinetics of gut bacteria such as glycans, which are indigestible for animals, including humans [16]. The primary degraders of GM can break down glycans and include the genera _Bacteroides_, _Bifidobacterium_, and _Ruminococcus_[17]. Furthermore, the diet can impact the metabolism and immune system of the host via several bioactive substances, including vitamins A and D, indole-derived compounds, and polyunsaturated fatty acids [18]. In turn, secondary plant metabolites, including terpenes (e.g., volatiles, glycosides, carotenoids, sterols), phenolics (e.g., phenolic acids, flavonoids, tannins), nitrogen-containing compounds (e.g., alkaloids and glucosinolates), and sulfur-containing compounds (e.g., glutathione, thionins, phytoalgebras), are known for their antioxidant, anti-inflammatory, antimicrobial, and potential anticancer effects, which contribute to overall health when included in the diet [19]. Plant-based diets are characterized by a predominant focus on the consumption of vegetables, legumes, whole grains, seeds, and fruits, while significantly reducing or excluding animal-derived products. The nutritional profiles of plant foods are linked to higher levels of essential vitamins, minerals, and dietary fiber, as well as to lower levels of saturated fats and cholesterol. Within this spectrum, vegetarian diets are often considered the most authentic and representative of plant-based eating, reflecting a clear prioritization of plant foods and a distinctive approach to dietary choices [20; 21; 22; 23]. Although vegetarian diets are probably the most sustainable dietary pattern existing and provide well-documented health benefits [24; 25], they may still present challenges, including food waste due to their short shelf life [26], as well as detrimental effects on both environmental and human health due to their reliance on toxic products for large-scale production [27]. In this complex scenario, fermented vegetables constitute a suitable option by effectively extending the shelf life of plant-based foods, reducing spoilage-associated waste, diminishing the levels of chemicals in vegetables, preserving overall nutritional quality, and aligning with consumer preferences for health-conscious and environmentally friendly food alternatives [28; 29; 30].