Malnutrition and Its Influence on Gut sIgA-Microbiota Dynamics

Abstract

In the current era, malnutrition is seen as both undernutrition and overweight and obesity; both conditions are caused by nutrient deficiency or excess and improper use or imbalance in the intake of macro and micronutrients. Recent evidence suggests that malnutrition alters the intestinal microbiota, known as dysbiosis. Secretory immunoglobulin A (sIgA) plays an important role in maintaining and increasing beneficial intestinal microbiota populations and protecting against pathogenic species. Depletion of beneficial bacterial populations throughout life is also conditioned by malnutrition. This review aims to synthesize the evidence that establishes an interrelationship between diet, malnutrition, changes in the intestinal flora, and sIgA levels. Targeted nutritional therapies combined with prebiotic, probiotic, and postbiotic administration can restore the immune response in the intestine and the host's homeostasis.

Keywords: gut microbiota; malnutrition; obesity; overweight; secretory IgA; underweight.

Figure 1

Categories of malnutrition. Undernutrition: includes wasting (low weight-for-height), stunting (low height-for-age), and underweight (low weight-for-age). Micronutrient deficiencies: refers to a lack of essential vitamins and minerals. Overnutrition: encompasses overweight, obesity, and diet-related noncommunicable diseases. Created using BioRender.com (accessed on 22 October 2024).

Figure 2

The most important factors that influence the gut microbiota composition in humans. Created using BioRender.com (accessed on 30 November 2024).

Figure 3

Undernutrition predominantly affects two vulnerable groups: newborns and the elderly, as well as patients with chronic diseases. This condition often results in dysbiosis, characterized by malabsorption and chronic inflammation, significantly increasing the risk of immune dysfunction and other health complications. Created using BioRender.com (accessed on 30 November 2024).

Figure 4

The unique role of sIgA in maintaining gut homeostasis. It helps regulate microbial communities and fortifies the mucosal barrier by directly interacting with gut microbes. sIgA binds to potentially harmful pathogens, preventing their adhesion to the gut lining while promoting the presence of beneficial microbial species. Dysregulation of sIgA can disrupt this balance, leading to microbial imbalances where harmful bacteria dominate, contributing to or exacerbating disease states. Created using BioRender.com (accessed on 30 November 2024).

Figure 5

Dietary interventions and nutritional supplements enhance fecal sIgA levels, promoting a diverse and healthy gut microbiota. Diets rich in fiber and fermented foods like yogurt and kimchi contribute to this effect. One of the mechanisms involved is the production of SCFAs, which possess anti-inflammatory properties and help maintain gut homeostasis. Created using BioRender.com (accessed on 30 November 2024).