The Immune System
Since your body can't naturally break down the mushroom cell walls, when choosing a mushroom supplement, it is vital that it is either extracted or prepared with a specific heat-treatment like Feel the Day™ products to give your body's immune system access to all the immune supporting constituents (polysaccarhides, beta glucans, terpenes etc.) hidden in the mushroom cell walls.
Polysaccharides and beta glucans increase the activity & impact of NK cells and macrophages.

What are Polysaccharides, Beta glucans, Macrophages and a Natural Killer Cells?!
Macrophages provide a first line of defense in the innate immune response to pathogens. They have the unique ability to engulf material and eliminate debris. In addition, they release biologically active proteins called cytokines and recruit other immune system cells to stop infections from spreading etc.

Natural killer (NK) cells are another vital part of your immune system which are a part of the lymphoid linage of white blood cells. When cytokines are secreted from macrophages it activates and facilitates the entry of NK cells into tissue to eliminate infected or stressed cells. The body also responds to viruses by secreting these cytokines because they disrupt viral replication and make the viruses more susceptible to attack by NK cells.