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How Beta Glucan Strengthens Your Immune System
By Jeff Rocco MD
Beta Glucan & Immune System Support for Endurance Athletes
Beta glucans are naturally occurring polysaccharides of D-glucose monomers linked by beta-glycosidic bonds. They serve as structural components of cell walls and energy stores in plant, fungal, and bacterial cell walls. They are not found in animal cell walls; however, an ever-growing body of research demonstrates that they have a pronounced supporting effect on human immune systems.
Beta glucans can cause direct stimulation of immune responses and act as training agents, amplifying immune responses when those trained cells are exposed to a secondary stimulus. The effects of this trained innate immunity (TRIM) appear to be an epigenetic process, with effects that can last for weeks to months and provide protection through altered immune responses against a range of viral exposures.
Promising from the Start
Yeast-derived beta glucans were first associated with immune function in 1941. Since that time, thousands of articles have documented the effects of beta glucan on immune function. Over 10 years ago, when I first reviewed literature regarding yeast-derived beta glucan, there was robust evidence in peer-reviewed scientific journals describing routes of absorption and many potential benefits, including but not limited to:
- Increases in the number and activity of natural killer cells (which attack viruses and reinforce immune actions),
- Activation of the complement system (anti-pathogen proteins), and
- Interesting animal studies demonstrating benefits against bacterial and viral infections.
Since that time our understanding of how beta glucan works has clarified, and a significant number of clinical studies have been published that further support these findings.
The Latest Research
Of particular interest are recent studies demonstrating the effects of beta glucan on upper respiratory tract infections (URTI), specifically in endurance athletes. Although the mechanism is not completely understood, athletes experience a transient state of immunosuppression after a highly demanding physical effort, leading to an “open window” for opportunistic infections. There is a greater incidence of URTI among ultra-marathoners and marathoners, though any endurance athlete can relate to the cycle of intense training followed by equally intense illness.
Beta glucan is a bolster for the immune system. It is not a replacement for vaccinations against respiratory viruses like COVID-19 or the seasonal flu.
Several placebo-controlled beta glucan studies in athletes have documented a decrease in post-marathon URTI symptomatic days, severity, and average missed workout days when treated with beta glucan. It has also been shown to reduce the duration of the “open window” by priming granulocytes for faster activation and cytokine production upon pathogenic challenges, increasing salivary IgA, improving circulating monocyte and T cell count, and altering the balance of T helper cytokines. All of this is to say that the net effect is to have a stronger, more efficient immune system, with less inflammation.
Perhaps nothing better proves the constant growth of beta glucan research than a 2020 study hypothesizing “that the use of oral Beta Glucan in a prophylactic setting could be an effective way to boost immune responses and abrogate symptoms in COVID-19” (Geller 2020). Another article focusing on respiratory virus infections supports a similar role for beta glucan as an adjuvant to COVID-19 vaccination (Jawhara 2020).
More Right Than We Knew
To summarize, the latest research involving beta glucan further reinforces earlier studies documenting increased potency and the efficiency of the human body’s already powerful immune system. It reinforces and primes your body’s natural defenses, helping to prevent lost training days or missed target events. This effect is especially critical during periods of peak training, when your body is at increased risk.
Castro, E DeMarco & P. C. Calder, H. M. Roche, Mol. Nutr. Food Res. 2021, 65, 1901071.
Geller, A. & J. Yan, Front in Immun., 2020, Jul vol 11, 1782.
Jawhara, S. Gut Pathog, 2020, 12:47.