Medicinal mushrooms have been used in traditional remedies for centuries, and research is beginning to examine how their compounds interact with the immune system. Their popularity has also spread to social media, where powdered mushrooms are often added to coffee and promoted for health benefits. The evidence, however, calls for a measured view rather than claims of dramatic effects.
One group of compounds attracting scientific interest is beta-glucans, complex sugars found in fungal cell walls. They can bind to receptors on macrophages and dendritic cells, including Dectin-1, and trigger immune responses. These can involve natural killer (NK) cells, T cells and cytokines, which help coordinate the body’s defences.
A 2020 review of medicinal mushrooms reported that beta-glucans, heteroglycans and immune-modulating proteins could activate several types of immune cell. But laboratory or blood-test changes do not necessarily show that a supplement prevents disease.
Among the mushrooms studied, reishi has evidence from a clinical trial involving 157 healthy adults. Participants who took 200 milligrams of reishi beta-glucan extract daily for 12 weeks showed increases in NK cells, CD4 and CD8 T cells, and IgA, an antibody involved in defending against viruses and bacteria. The study measured immune biomarkers; its authors did not establish that the supplement protects against illness.
Maitake contains a group of beta-glucans known as D-fraction, which has been studied for its effects on immune cells and inflammatory signalling. Research involving cancer patients reported increased NK-cell activity. Shiitake contains lentinan, a fungal beta-glucan used as an adjunct treatment for gastric cancer in Japan since 1986. The source also describes findings for Agaricus blazei, including increased NK-cell activity and reduced inflammation markers in clinical-trial analyses.
Cordyceps has also been studied for compounds that may influence both antibody-based and cellular immune responses. A recent review of five medicinal mushrooms used in oncology said their immune mechanisms had been demonstrated experimentally, while urging caution about applying those findings to healthy people.
A 2021 systematic review associated mushroom beta-glucan supplements with fewer respiratory infections and increased NK-cell levels among athletes. Results varied across studies, however, including according to the dose, preparation and participants. The central challenge is distinguishing changes in immune measurements from evidence that people actually become less likely to get sick.
The reported studies found no dangerous side effects at the doses examined, but the available evidence does not support treating medicinal mushrooms as a guarantee against disease or as a substitute for medical care.】【。}
Sources: elDiario.es.