Journal of Nutrition & Food Sciences
Open Access

Dietary Determinants of Mucosal Immune Health and Disease

Tomasz Kowalski^{* *}Correspondence: Tomasz Kowalski, Department of Food Technology and Nutrition, Warsaw University of Life Sciences, Warsaw, Poland, Email:

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Description

Mucosal immunology, the study of immune responses occurring at mucosal surfaces such as the gastrointestinal, respiratory and genitourinary tracts, has witnessed major advancements in recent years. As these interfaces are the first points of contact between the external environment and the host, mucosal immunity is central to both defense against pathogens and tolerance to non-harmful antigens, including food and commensal microbiota. Emerging evidence now strongly underscores the role of nutrition as a fundamental modulator of mucosal immunity, with significant implications for human health, disease prevention and therapeutic interventions.

One of the most fascinating developments in mucosal immunology is the characterization of the Gut-Associated Lymphoid Tissue (GALT), which comprises more than 70% of the body's total immune cells. This system is in constant interaction with antigens derived from diet and microbiota. Its ability to distinguish between harmful pathogens and harmless or beneficial entities is critical for maintaining immune homeostasis. When this balance is disrupted, it can lead to inflammatory and autoimmune diseases such as Inflammatory Bowel Disease (IBD), food allergies and systemic inflammation. Nutrition, by influencing microbial composition, epithelial barrier function and immune cell behavior, is emerging as a powerful determinant of mucosal immune health.

From a nutritional standpoint, macronutrients and micronutrients directly impact mucosal immune functions. Proteins, fats and carbohydrates are more than just energy sources—they shape the metabolic environment of the gut and affect immune signaling pathways. For instance, high-fat diets, especially those rich in saturated fats, have been shown to disrupt tight junctions in the intestinal epithelium, increasing mucosal permeability (“leaky gut”) and promoting systemic endotoxemia. This condition, in turn, triggers chronic low-grade inflammation, a known contributor to metabolic disorders and immune dysregulation.

Conversely, certain fatty acids such as Short-Chain Fatty Acids (SCFAs)—notably acetate, propionate and butyrate—produced by microbial fermentation of dietary fibers, exhibit immunoregulatory properties. Butyrate, in particular, promotes the differentiation of regulatory T cells (Tregs), enhances the integrity of the gut barrier and suppresses pro-inflammatory cytokine production. These findings position dietary fiber not only as a metabolic asset but also as a key factor in immunological health. Thus, dietary patterns rich in whole grains, fruits and vegetables support mucosal immunity through both direct nutrient action and microbiota-mediated pathways.

Micronutrients such as vitamin A, vitamin D, zinc and iron also have established roles in mucosal immunology. Vitamin A, through its metabolite retinoic acid, directs lymphocyte trafficking to the gut mucosa and supports IgA production, which is the dominant immunoglobulin at mucosal surfaces. Vitamin D, known for its role in bone health, also modulates epithelial barrier function and dampens inflammatory responses by supporting the activity of Tregs and dendritic cells. Deficiencies in these micronutrients have been associated with increased susceptibility to infections and inflammatory conditions localized at mucosal sites.

Beyond individual nutrients, the overall dietary pattern has profound implications for mucosal immune function. The Western diet, characterized by high intake of refined sugars, animal fats and low fiber, has been linked to dysbiosis—an imbalance in gut microbiota composition. Dysbiosis impairs mucosal immunity by reducing SCFA production, impairing epithelial barrier integrity and favoring the expansion of pathobionts. On the other hand, Mediterranean-style diets and plant-based diets, which are high in polyphenols, fiber and healthy fats, have been associated with enhanced mucosal immune responses, reduced inflammation and improved clinical outcomes in diseases like IBD and asthma.

An especially promising area is the influence of nutrition on the mucosal microbiota-immune axis during early life. Breast milk, rich in immunoglobulins, Human Milk Oligosaccharides (HMOs) and beneficial microbes, plays a critical role in shaping the infant mucosal immune system. Early-life nutrition has long-term consequences for immune tolerance and disease risk. For example, inadequate exposure to microbial diversity or key nutrients during the first 1000 days of life can predispose individuals to allergic and autoimmune diseases.

In conclusion, the intersection of mucosal immunology and nutrition represents a dynamic and impactful field that holds tremendous promise for enhancing human health. As we deepen our understanding of how specific nutrients and dietary patterns shape mucosal immune responses, we move closer to developing targeted nutritional strategies for disease prevention and immune optimization. Going forward, a comprehensive approach involving immunologists, nutritionists, microbiologists and clinicians will be significant in translating this knowledge into meaningful health outcomes.