Yeast Beta Glucan – the Secret Weapon for the Immune System

A Short History of Trained Innate Immunity 

Although certain yeast beta glucans have been recognised as highly efficacious ingredients for immune support for over 20 years, the most recent research exploring the detailed mechanism of action has revealed some surprising findings.  The established scientific thinking from the past 75 years has been that only the adaptive immune system has the capacity to “remember” past experiences with infectious and inflammatory challenges and respond more effectively to them upon a future encounter.  This dogma has now been dismantled with the discovery of trained innate immunity, thanks in large part of the exploration of how specific yeast beta glucans with unique molecular structures support immune health.

Measuring Gene Expression Revolutionises the Quest for Evidence of Innate Immune Training In Vivo

This recent paradigm shift in our understanding of the capabilities of the innate immune system to include trained immunity traces its roots to epidemiologic research in the early 2000’s.  This was followed by a set of human clinical trials published starting in 2009 which provided evidence of the physical health benefit resulting from trained innate immunity ^1-10 .  However, most of the published cellular data revealing trained innate immunity has come from experiments in vitro and pre-clinical models ^11-14, not in human clinical studies.

In the past two years, several clinical reports have now been published describing innate immune training at the cellular level in clinical trials when healthy volunteers consume a particular yeast beta glucan ^15-17.  Previously, the method available to test if the immune system had become trained in human volunteers involved challenging people with physical or lifestyle stressors to provoke an immune response and measuring functional changes that indirectly reflect innate immune training.

The newest publications provide a strong example of direct measurement of innate immune training in humans by measuring changes in gene expression (use) of specific genes that make up cellular innate immune training programs.  They also demonstrate that consumption of a specific yeast beta glucan with a defined molecular structure trains the innate immune system in healthy volunteers and not just laboratory models.  This has revolutionised the study of innate immune training in vivo.  Using the proposed gene expression signature, it seems possible to observe and monitor innate immune training in near real time in healthy people without challenging or unnecessarily stimulating the immune system.

The gene use signature includes genes that are known to have critical roles in the innate immune response to foreign challenges.  Some of these genes code for proteins that are key parts of cellular signalling pathways used by the yeast beta glucan receptor, Dectin-1.  Other genes are part of the innate immune training cellular control program.  Identifying and measuring this signature provides strong evidence that innate immune training occurs in healthy people following daily consumption of a specific yeast beta glucan.  These studies also provide greater insight into how this well characterised yeast beta glucan supports a healthy immune response.  Greater understanding of how this specific type of innate immune training works helps to reassure consumers that this ingredient provides efficacious support for a healthy immune response.

The Importance of Structure–Function Clarity

Although beta glucans are widely recognised, there remains significant confusion in the market about the differences between beta glucan sources such as yeast, cereal, and mushroom.  What sets certain yeast beta glucans apart is their specific molecular structure, including the configuration of (1,3/1,6) linkages and the tertiary conformation that allows them to interact effectively with innate immune receptors like Dectin-1.  These structural features are foundational to whether the body can mount a meaningful trained innate immune response.  By highlighting the importance of well-defined structure–function relationships, this emerging research gives both scientists and product developers a clearer framework for evaluating beta glucan quality.

Consumer and Market Context: Why This Science Matters Now

Over the past several years, consumers have increasingly shifted toward a more proactive and holistic understanding of immune health—one that emphasises everyday resilience, not just seasonal defence.  This shift is reflected in strong ongoing demand for functional foods, beverages, and supplements that provide clinically validated benefits and are grounded in credible mechanisms of action.  As consumers become more discerning, ingredients supported by emerging scientific insights, such as trained innate immunity, stand out as particularly relevant. Yeast beta glucans with well characterised structures and robust clinical substantiation are uniquely positioned to meet these expectations, offering an immune support solution that aligns with how consumers now think about “living well” rather than simply managing illness.

What Does the Future Hold?

Training of the innate immune system has been happening long before we were aware of the concept or understood some of its benefits for our everyday health.  For nearly two decades research has repeatedly shown that daily consumption of a well-studied yeast beta glucan supports immune health, reducing the severity and incidence of symptoms from upper respiratory challenges ^1,2,4,7-10.  Using the recently proposed gene expression signature of a trained innate immune system in healthy people, future research can finetune interventions such as yeast beta glucans to more effectively optimise support for a healthy lifestyle and immune health.

Additionally, by using powerful new data informatics tools coupled with new results from clinical studies, researchers are very likely to uncover new ways that training the innate immune system leads to other benefits to our everyday health and wellness.  We look to the future with great optimism and excitement about what science will teach us about the benefits of training the innate immune system to support our health.

• References
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  2. Fuller R, Moore MV, Lewith G, et al. (2017)  Yeast-derived beta 1,3/1,6 glucan, upper respiratory tract infection and innate immunity in older adults.  Nutrition 39-40: 30-35.  DOI: 10.1016/j.nut.2017.03.003
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