Benefits of Shiitake Mushroom for Your Immune System

With all the hype surrounding the various species of functional mushrooms, it can be surprising to learn that regular grocery store Shiitake mushrooms also possess some powerful functional benefits and therapeutic properties. One of these benefits is their effect on the health of your immune system.

Aside from Shiitake's direct immune-boosting properties, several other health benefits of Shiitake mushrooms contribute to a more holistic improvement of your body's immune response.

1. Shiitake Mushrooms Are High in Polysaccharides

Shiitake mushrooms are great for nutrition due to their complex vitamins and polysaccharide contents.

Polysaccharides are commonly understood to be beneficial for several reasons, including their immune-boosting properties. As noted by this study, the polysaccharides obtained from natural sources (mushrooms among them) "[Activated] macrophages and [increased] their phagocytic activity," among other things.

Macrophages are a type of white blood cell that engulfs and kills invading pathogens, disposes of the dead material, and stimulates the action of other immune cells.

2. Shiitake Mushrooms May Be Anti-Cancerous

Another benefit of the polysaccharide content of mushrooms is that they might be effective in fighting cancers. A separate study found supporting evidence that the polysaccharide extracts of various mushrooms (Shiitake included) possessed some cancer-preventative and anti-tumour effects in animal models and supporting in vitro experiments.

3. Shiitake Mushrooms May Have Anti-Aging Properties

It is normal for an individual's immune system to degrade with age. As noted by a study published in The Journal of Clinical Investigation, one of the effects of age on the immune system is the "Reduced production of B and T cells in bone marrow and thymus and diminished function of mature lymphocytes in secondary lymphoid tissues." Essentially, you have fewer immune cells, which results in a slow and less effective response to invading pathogens.

Interestingly, there is existing research on the efficacy of Shiitake mushrooms to combat this age-related immune decline. The linked study found that not only did the fruiting body extracts of Shiitake mushrooms "Restore the age-attenuated immune responses [in elderly rats] by increasing cytokine levels in the blood," but also that they could "Partly reverse the age-altered composition of gut microbiota."

Improving gut bacteria is essential as around 70% of the body's immune response capability is located in the gut. Improving the balance of healthy gut bacteria will improve the overall capability of your immune system.

4. Shiitake Mushrooms May Be Antimicrobial and Anti-fungal

A feature of mushrooms that often goes overlooked is that they need to have inherent anti-bacterial and anti-fungal properties to survive in the dingy conditions to which they are accustomed. Dark and humid environments are breeding grounds for both bacteria and fungi. And, as noted by this study, these properties can be isolated and refined for other applications.

Though the linked study looked at the properties of many different kinds of mushrooms, those that were found for Shiitake mushrooms specifically are as follows:

• The oxalic acid content of Shiitake mushrooms had potent antimicrobial effects against Staphylococcus aureus and other bacteria.
• Ethanol extracts of Shiitake mushrooms exhibited antiprotozoal activity against Paramecium caudatum bacteria.
• Shiitake mushroom extracts exhibited antiviral activity and completely prevented HIV-induced cytopathic effects (structural changes in host cells caused by viral cells).

Are Shiitake Mushrooms Safe to Eat?

It seems unlikely something with this many benefits would be completely safe to eat, but this appears to be the case for Shiitake mushrooms, both in food and as supplements, within reason. There have been some reported side effects when Shiitake mushroom powdered extracts have been consumed in large amounts, or when wild and natural shiitake mushrooms have been consumed without prior cooking. These include stomach discomfort and skin rashes but only in rare cases.

So long as you don't have any preexisting conditions (such as a mushroom or mould allergy), Shiitake should be safe for consumption. If you are unsure about the risk they propose to you specifically, be sure to consult with a doctor to get an accurate assessment.