In recent times, the emergence of viral infections, including the SARS-CoV-2 virus, the monkeypox virus, and, most recently, the Langya virus, has highlighted the devastating effects of viral infection on human life. There has been significant progress in the development of efficacious vaccines for the prevention and control of viruses; however, the high rates of viral mutation and transmission necessitate the need for novel methods of control, management, and prevention. In recent years, there has been a shift in public awareness on health and wellbeing, with consumers making significant dietary changes to improve their immunity and overall health. This rising health awareness is driving a global increase in the consumption of functional foods. This review delves into the benefits of functional foods as potential natural means to modulate the host immune system to enhance defense against viral infections. We provide an overview of the functional food market in Europe and discuss the benefits of enhancing immune fitness in high-risk groups, including the elderly, those with obesity, and people with underlying chronic conditions. We also discuss the immunomodulatory mechanisms of key functional foods, including dairy proteins and hydrolysates, plant-based functional foods, fermentates, and foods enriched with vitamin D, zinc, and selenium. Our findings reveal four key immunity boosting mechanisms by functional foods, including inhibition of viral proliferation and binding to host cells, modulation of the innate immune response in macrophages and dendritic cells, enhancement of specific immune responses in T cells and B cells, and promotion of the intestinal barrier function. Overall, this review demonstrates that diet-derived nutrients and functional foods show immense potential to boost viral immunity in high-risk individuals and can be an important approach to improving overall immune health.

Fermented foods have long been known to have immunomodulatory capabilities, and fermentates derived from the lactic acid bacteria of dairy products can modulate the immune system. We have used skimmed milk powder to generate novel fermentates using Lb. helveticus strains SC234 and SC232 and we demonstrate here that these fermentates can enhance key immune mechanisms that are critical to the immune response to viruses. We show that our novel fermentates, SC234 and SC232, can positively impact on cytokine and chemokine secretion, nitric oxide (NO) production, cell surface marker expression, and phagocytosis in macrophage models. We demonstrate that the fermentates SC234 and SC232 increase the secretion of cytokines IL-1β, IL-6, TNF-α, IL-27, and IL-10; promote an M1 pro-inflammatory phenotype for viral immunity via NO induction; decrease chemokine expression of Monocyte Chemoattractant Protein (MCP); increase cell surface marker expression; and enhance phagocytosis in comparison to their starting material. These data suggest that these novel fermentates have potential as novel functional food ingredients for the treatment, management, and control of viral infection.

Fermented foods and ingredients, including furmenties derived from lactic acid bacteria (LAB) in dairy products, can modulate the immune system. Here, we describe the use of reconstituted skimmed milk powder to generate novel fermentates from Lactobacillus helveticus strains SC232, SC234, SC212, and SC210, and from Lacticaseibacillus casei strains SC209 and SC229, and demonstrate, using in vitro assays, that these fermentates can differentially modulate cytokine secretion via bone-marrow-derived dendritic cells (BMDCs) when activated with either the viral ligand loxoribine or an inflammatory stimulus, lipopolysaccharide. Specifically, we demonstrate that SC232 and SC234 increase cytokines IL-6, TNF-α, IL-12p40, IL-23, IL-27, and IL-10 and decrease IL-1β in primary bone-marrow-derived dendritic cells (BMDCs) stimulated with a viral ligand. In contrast, exposure of these cells to SC212 and SC210 resulted in increased IL-10, IL-1β, IL-23, and decreased IL-12p40 following activation of the cells with the inflammatory stimulus LPS. Interestingly, SC209 and SC229 had little or no effect on cytokine secretion by BMDCs. Overall, our data demonstrate that these novel fermentates have specific effects and can differentially enhance key immune mechanisms that are critical to viral immune responses, or can suppress responses involved in chronic inflammatory conditions, such as ulcerative colitis (UC), and Crohn’s disease (CD).

Fermented foods have long been known to have immunomodulatory capabilities and fermentates derived from the lactic acid bacteria of dairy products can modulate the immune system. We have used skimmed milk powder to generate novel fermentates using Lb. helveticus strains SC234 and SC232 and we demonstrate here that these fermentates can enhance key immune mechanisms that are critical to the immune response to viruses. We show that our novel fermentates SC234 and SC232 can positively impact on cytokine and chemokine secretion, nitric oxide (NO) production, cell surface marker expression, and phagocytosis in macrophage models. We demonstrate that fermentates SC234 and SC232 increase the secretion of cytokines IL-1β, IL-6, TNF-α, IL-27, and IL-10, promote an M1 proinflammatory phenotype for viral immunity via NO induction, decreases chemokine expression of Monocyte Chemoattractant Protein (MCP), increasing cell surface marker expression, and enhance phagocytosis in comparison to their starting material. These data suggest that these novel fermentates have potential as novel functional food ingredients for the treatment, management and control of viral infection.

Some lactic acid bacteria (LAB) can synthesize exopolysaccharides (EPS) during fermentation that enhance the functional value of food products and may confer health benefits including immunomodulation. We aimed to examine the potential anti‐inflammatory effects of EPS from three Lactobacillus species in the context of chronic inflammatory diseases, including Crohn's disease (CD) and ulcerative colitis (UC). Lactobacillus delbrueckii subsp. bulgaricus 327 (LB327), Lentilactobacillus kefiri 13 (LKF13), and Lacticaseibacillus rhamnosus 28 (LRH28) were cultivated in MRS media, yielding 225–260 mg/L EPS. Biomass and EPS yields were harvested and quantified. The chemical structure of the purified EPS was subsequently characterized using Fourier‐transform infrared (FTIR) spectroscopy to identify functional group. EPS samples were tested for immunomodulatory potential using J774A.1 murine macrophages and JAWS II dendritic cells under lipopolysaccharide (LPS) stimulation. Cell viability remained unaffected. EPS reduced pro‐inflammatory cytokines IL‐1β, TNF‐α, increased anti‐inflammatory IL‐10, dual‐role IL‐6, and exerted minimal effect on chemokine secretion in LPS‐induced inflammatory models. Overall, LB327, LFK13, and LRH28 demonstrated anti‐inflammatory effects, modulating cytokine profiles while preserving chemokine signaling. These findings highlight the potential of LAB‐derived EPS as functional food ingredients capable of immune regulation, suggesting a dietary supportive role alongside conventional therapies in chronic inflammatory diseases including UC and CD.

Fermented foods and ingredients, including fermentates derived from lactic acid bacteria (LAB) in dairy products, can modulate the immune system. Here we describe the use of reconstituted skimmed milk powder to generate novel fermentates from Lactobacillus helveticus strains SC232, SC234, SC212, and SC210, and from Lacticaseibacillus casei strains SC209 and SC229, and demonstrate using in vitro assays that these fermentates can differentially modulate cytokine secretion by bone marrow derived dendritic cells (BMDCs) when activated with either the viral ligand, loxoribine, or an inflammatory stimulus, lipopolysaccharide. Specifically, we demonstrate that SC232 and SC234 increase cytokines IL-6, TNF-α, IL-12p40, IL-23, IL-27 and IL-10, and decreased IL-1β in primary bone marrow derived dendritic cell (BMDCs) stimulated with a viral ligand. In contrast exposure of these cells to SC212 and SC210 resulted in increased IL-10, IL-1β, IL-23, and decreased IL-12p40 following activation of the cells with the inflammatory stimulus LPS. Interestingly SC209 and SC229 had little or no effect on cytokine secretion by BMDCs. Overall, our data demonstrates that these novel fermentates have specific effects and can differentially enhance key immune mechanisms that are critical to viral immune responses, or can suppress responses involved in chronic inflammatory conditions, such as Ulcerative Colitis (UC), and Crohn’s disease (CD).