Effects of Mushrooms on Immune Functions

Mushrooms have been used in traditional medicine for thousands of years.^1,2

Fungi, including mushrooms and yeast, are rich in compounds called beta glucans, which have antiviral and immune-supporting effects.^3,4

In human studies, taking beta glucans was shown to boost immune response,⁵ reduce the number, severity, and duration of upper respiratory infections^6-8 (such as colds and flu), and ease symptoms of seasonal allergies.⁹

Researchers have identified three mushrooms with particularly strong immune benefits: shiitake,¹⁰ maitake,¹¹ and chaga.¹²

Combining isolated beta glucans with mushroom extracts may offer well-rounded immune support benefits.

Beta Glucans Boost Immunity

Beta glucans are polysaccharides bound within the walls of fungi, bacteria, and some whole grains like oats. They are found in particularly high amounts in mushrooms and can be isolated from yeast.

They can help support immune health and boost defenses against viruses and other pathogens.^13-15

They have also been shown in preclinical studies to reduce the effects of endotoxins, harmful byproducts of bacterial infections that cause inflammation.^16,17

There are two types of immune responses: innate and adaptive.^18,19 Innate immunity is the body’s first line of defense. Macrophages engulf and neutralize viruses and other pathogens, while natural killer (NK) cells target and destroy unhealthy cells that are cancerous or infected by viruses and other pathogens.

Adaptive immunity is a more specific, targeted response that develops after exposure to a particular pathogen and provides long-term protection. This response is driven by T-cells and B-cells.

Beta glucans activate and stimulate both innate and adaptive immunity.^10,20,21

As we age, our immune system weakens and loses its ability to fight off infections and cancer, a condition known as immunosenescence.

Animal studies indicate that beta glucan intake can prevent or even reverse immunosenescence.^20,22

Renewing these immune responses is particularly important to older individuals.

Mushrooms With Maximum Benefits

Mushrooms contain health-promoting compounds, including indoles, polyphenols, and carotenoids.

Beta glucans are among these biologically active immune-supporting compounds found in mushrooms.²³

There are thousands of species of mushrooms that have health benefits.²⁴ Three mushrooms that have been found to provide especially strong immune effects are: shiitake, maitake, and chaga.

Shiitake

Shiitake mushrooms have long been used in traditional Chinese medicine.

In an animal model of severe bacterial lung infection, beta glucans from shiitake mushrooms significantly reduced the bacterial load in the lungs and improved health.²⁵

Cell studies show that shiitake mushrooms inactivate viruses and downregulate viral replication.^26,27

As demonstrated in a clinical study, these immune-boosting effects are likely due to shiitake’s ability to increase the number of immune system cells, including T-cells and NK cells.¹⁰

Shiitake mushrooms also decrease markers of harmful chronic inflammation and stimulate secretion of antibodies that protect the gut.¹⁰

Maitake

Maitake mushrooms, often used in Asian cuisine, also provide powerful immune benefits.

In animal studies, maitake extract significantly increased NK cells and bacterial elimination.^28,29 This effect was even more pronounced when blended with shiitake extract.²⁹

Maitake extract also promoted secretion of interferon gamma (IFN-γ), a protein that blocks viral replication.²⁹

Chaga

Chaga mushrooms are native to colder climates and often grow on birch trees. They are immuno-modulators, and in preclinical studies chaga extract has shown antiviral activity.³⁰

In a study of immune-compromised mice, chaga extract restored immune cells to nearly normal levels and regulated the levels of tumor necrosis factor alpha (TNF-α), a marker of inflammation, indicating that chaga extract prevented excess inflammation.³¹

In preclinical studies, chaga extract has also exhibited beneficial activity against a wide range of viruses.^12,30,32

Defense Against Infectious Diseases

Beta glucans have been shown to help protect against and treat infections from bacteria, viruses, and parasites.^33-35

In various placebo-controlled human trials, participants were randomized to receive beta glucans or placebo. These trials used at least 250 mg of beta glucans daily.

Participants who were part of the beta-glucan group had:^5-8,36,37

• Reduced upper respiratory infections, including colds and flu,
• Shortened duration of symptoms,
• Fewer lost workdays,
• Increased circulating interferon, and
• Higher levels of salivary antibodies, which protect against respiratory and digestive pathogens.

Another study investigated beta glucans’ effect on adults who suffer from moderate seasonal ragweed allergies.

Compared to a placebo, those who took 250 mg of beta glucans daily had a reduction in the duration and intensity of allergy symptoms, along with improvements in sleep, quality of life, energy, and mood.⁹

WHAT YOU NEED TO KNOW

Mushrooms’ Benefits for the Immune System

• Mushrooms have been used in traditional medicine for thousands of years.
• Fungi, including mushrooms and yeast, are rich in many active compounds responsible for immune-supporting benefits, including beta glucans.
• In human trials, taking beta glucans reduced the number and duration of upper respiratory infections, including colds and flu, and relieved seasonal allergy symptoms.
• In a meta-analysis of observational studies, those who consumed the most mushrooms had a 34% lower risk of cancer than those who ate none.
• Combining beta glucans with extracts of the immune-supporting mushrooms shiitake, maitake, and chaga may optimize the immune system’s ability to ward off infections and other illnesses.

Better Gut Health

There are a variety of microorganisms in the digestive tract. A balanced microbiome is critical to fighting infection and maintaining immune health.³⁸

One way beta glucans and mushrooms support immunity is by promoting the growth of healthy microorganisms in the gut.

Beta glucans serve as a prebiotic fiber that nourishes beneficial bacteria.13,39

Preclinical and clinical studies have shown a healthy microbiome contributes to a robust immune response, supports a healthy gut lining and digestive health, and inhibits growth of disease-causing bacteria and inflammation.^13,40-42

In addition, beta glucans promote the production of short-chain fatty acids, which are vital for gut health and maintaining the integrity of the gut barrier.^13,40,42

Fighting Cancer

In September 2021, scientists with the College of Medicine at Pennsylvania State University published results from a cohort study of over 30,000 people. They also included their data in a meta-analysis of prospective studies that had over 600,000 participants, on the relationship between mushroom intake and mortality.⁴³

They found that higher mushroom consumption correlated with a lower risk of death from any cause.

This study had several major strengths, including the fact that it analyzed a nationally representative sample of the American adult population, and involved a very comprehensive meta-analysis of cohort studies around the world.

When operating properly, the immune system can identify and neutralize cancerous cells. By supporting immunity, mushrooms may improve this ability.

One meta-analysis of observational studies that included over 615,000 people, nearly 20,000 of whom were cancer patients between 1966 and 2020, found that those who consumed the greatest amount of mushrooms had a 34% decreased risk of cancer compared to those who ate the least.⁴⁴

Beta glucans and other compounds in shiitake, maitake, and chaga mushrooms increase the activity of protective signaling proteins that can inhibit tumor cell growth.^30,45

A combination of beta glucans and extracts of these mushrooms can provide a wide range of immune- supportive compounds.

Summary

Mushrooms have been used medicinally for thousands of years. Research shows that they contain compounds called beta glucans, which support immunity and gut health and help protect against viruses and cancer.

A blend of beta glucans isolated from yeast, with extracts of shiitake, maitake, and chaga mushrooms may offer well-rounded immune support benefits.

If you have any questions on the scientific content of this article, please call a Life Extension  Wellness Specialist at 1-866-864-3027.

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