Menopause brings a series of endocrine changes that significantly increase the risk of developing metabolic syndrome (MetS), a condition characterized by central obesity, dyslipidemia, hypertension, and insulin resistance. In this context, the gut microbiota has gained relevance as a key modulating factor in the pathophysiology of MetS in postmenopausal women. The decline in estrogen levels affects microbial diversity and composition, promoting a dysbiotic environment marked by the loss of beneficial bacteria, such as Akkermansia muciniphila and Bifidobacterium spp., and an increase in proinflammatory, lipopolysaccharide (LPS)-producing microorganisms, such as Proteobacteria and Escherichia coli. This imbalance leads to increased intestinal permeability and endotoxin translocation, triggering systemic low-grade inflammation associated with various MetS components. Clinical studies have identified correlations between specific microbial taxa, metabolites such as imidazole propionate and phenylacetylglutamine, and clinical markers of metabolic dysfunction. In this scenario, dietary intervention emerges as an effective therapeutic tool. Dietary patterns like the Mediterranean diet - rich in polyphenols, fiber, and monounsaturated fats - have shown beneficial effects on gut microbiota modulation, enhancing short-chain fatty acid production, reducing inflammation, and improving metabolic homeostasis. Likewise, the DASH diet and plant-based dietary patterns have demonstrated potential in the prevention and management of MetS in postmenopausal women. In conclusion, the interaction between gut microbiota, metabolism, and postmenopausal hormonal changes represents a critical axis in the development of MetS. Personalized dietary approaches aimed at restoring eubiosis may offer an effective strategy to improve metabolic health in this vulnerable population.

Micronutrient deficiencies are commonly observed in patients with obesity and may persist or worsen following bariatric and metabolic surgery. Emerging evidence suggests that micronutrients play a fundamental role in tissue repair, collagen synthesis, immune function, and inflammatory regulation processes that are critical in postoperative healing. Therefore, deficiencies in these nutrients could be pivotal in understanding and preventing postoperative complications. However, the potential link between preoperative micronutrient status and the development of postoperative complications, such as anastomotic or gastric fistula, remains underexplored. This narrative review aims to investigate the correlation between specific micronutrient deficiencies (e.g., vitamin C, zinc, selenium, vitamin A, and iron) and the incidence of fistula after bariatric surgery. We will discuss the underlying biological mechanisms, clinical evidence, and possible preventive strategies, including preoperative screening and targeted supplementation. Our aim is to highlight the often-overlooked micronutrient deficiency as a risk factor in patients undergoing bariatric surgery, both in the pre- and postoperative periods, and to propose a more comprehensive approach to patient assessment and management.