A clinical study using single-cell genetic analysis found that regular consumption of kimchi strengthens the immune defense and can also prevent excessive immune reactions[1]. Researchers have observed increased activity of antigen-presenting cells (APCs), which recognize pathogens and present them to other immune cells[1][3]. The study also noted positive changes in CD4+ T lymphocytes, which coordinate and regulate the immune response[2][3]. According to the authors, different fermentation methods had different effects, and versions fermented with starter cultures were slightly more effective according to some results[3]. The authors reported that kimchi has two actions at the same time: it activates defense cells and suppresses an exaggerated immune response[1][2]. The lead scientists plan to expand international research on kimchi and lactobacilli in relation to immune and metabolic health[1].