The immune system mainly consists of innate and adaptive immunity that could provide defense against cancer, viruses, and bacteria. Chemical compounds in foods could involve pathophysiological mechanisms to regulate signal transduction at cellular and molecular levels, ultimately impacting the progression of diseases. In recent years, nutraceuticals, functional foods, and food supplements - hot topics in food research - have emerged to enhance the capacity of immune regulation to improve disease problems, although the mechanisms are widely unknown. Healthy diets containing probiotics, vitamins, nutraceuticals, functional foods, and multi-nutrient supplements, can play a critical role in solidifying the immune system. For example, some milk proteins and peptides could act as adjuvants for antiviral therapy. While vitamins (C, D, E, B12, folic acid), antioxidants (carotenoids, coenzyme Q10, polyphenols, curcumin), minerals (Zn, Fe, Se), omega-3 fatty acids, and probiotics could modulate the body's immune responses.

Nevertheless, the interaction between nutrition and the immune system is complicated because of the different immune responses in various stages, specific micronutrients, the synergistic function of vitamins and minerals, and the deficiency of pivotal nutrients. In addition, the nutrition status and intake capacity in person for nutraceuticals, functional foods, and food supplements could also greatly impact the function of the immune system, including the innate immune system and adaptive immune system. There are several classical immune-related pathways, like NF-κB, MAPKs, and JAK/STAT signal pathways, involved in the regulation between nutrition and the immune system. STAT1 and STAT3 are members of the STAT transcription factor family, which are keys to the regulation of macrophage activity. STAT1 can promote the M0 macrophage polarization into the M1 phenotype, and STAT6 can increase the M0 macrophage transformation into the M2 phenotype. MAPK is involved in the activities of myeloid-derived cells and human monocyte-derived macrophages. Whereas, NF-κB signals play an essential role to modulate the activity of B cells and T cells. Hydroxytyrosol acetate (HTy-Ac), an extra virgin olive oil (EVOO) polyphenol, could modulate the oxidative events and inflammatory reactivity through JAK/STAT, MAPKs, and NF-κB pathways. Moreover, dietary oleuropein and its new acyl-derivate could also alleviate murine lupus nephritis by suppressing JAK/STAT, NF-κB, and MAPK signaling pathways.

This Special Issue invites original research and review articles that provide novel findings on cellular and molecular mechanisms involved in the field of the interaction between nutrition and the immune system. This Special Issue aims to feature research on, but not limited to, the specific mechanisms of nutraceuticals, functional foods, and dietary supplements and their impact on the innate immune system and adaptive immune system. Insights in the areas of intracellular and extracellular signals, effective targeted therapy strategies, and other investigating challenges and opportunities associated with targeting immune cells are also welcome.

Potential topics include but are not limited to the following:

• Intracellular and extracellular signaling pathways in the interaction between nutrition and the immune system.
• Novel nutraceuticals, functional foods, and dietary supplements as immunomodulatory agents
• Clinical evidence for the mechanism of novel nutraceuticals, functional foods, and dietary supplements
• The study of single-cell RNA sequencing, bulk RNA sequencing, and spatial transcriptomics for the interaction between nutrition and the immune system
• Regulatory roles of non-coding RNAs and exosomes in the interaction between nutrition and the immune system
• Regulatory roles of immune cells in disease state by nutrition
• Animal models for researching the interaction between nutrition and the immune system in-vivo