Shiitake mushroom (Lentinula edodes) has a history of use in traditional East Asian medicine for enhancing vitality and longevity, but its modern use in supporting autoimmune disorders is primarily based on scientific exploration of its immunomodulatory properties. Shiitake contains beta-glucans and a unique polysaccharide called lentinan, which have been shown in preclinical studies to modulate the immune system by stimulating certain immune cells, such as macrophages and natural killer cells. These effects have led to interest in their potential to balance immune responses, which could theoretically benefit individuals with autoimmune disorders.

However, the scientific evidence for using shiitake mushrooms specifically to support or treat autoimmune disorders in humans is limited. Most clinical research focuses on its role as an adjunct in cancer therapy or general immune support, rather than directly treating autoimmune conditions. There are few, if any, large-scale randomized controlled trials examining shiitake for autoimmune diseases such as lupus, rheumatoid arthritis, or multiple sclerosis. Some studies suggest that shiitake extracts can regulate cytokine production and reduce inflammation, but these findings are largely from animal models or in vitro experiments.

In summary, while there is a scientific basis for investigating shiitake mushrooms in the context of immune modulation, current evidence supporting their use for autoimmune disorders in humans is preliminary and not robust. More clinical research is needed to confirm efficacy and safety for this specific application.