Yeast are organisms that are widely present in the foods we eat and our environment. Mankind has utilized yeast for thousands of years to ferment food products, with historical records of ancient Egyptians confirming this practice. However, over the years, yeast have developed a reputation for being bad for our health. When it comes to a healthy diet, we are often counseled to avoid foods that are high in yeast and those that feed yeast in our digestive tract. It is likely that this understanding of yeast is severely incomplete and, from the perspective of health benefits, tremendously unfair. Just as we have come to categorize bacteria as bad and good depending on their effects on the body (probiotic bacteria being the good ones and pathogenic bacteria being bad), researchers are uncovering a whole new perspective on yeast. In fact, yeast can also be good or bad, probiotic (supporting the overall health of the microbiome) or pathogenic. Just like bacteria, yeast and other organisms make up the human microbiome and are key contributors to health and disease. So, when it comes to yeast and whether they should be avoided or not, the answer is it depends, not only on your health circumstances, but also on the properties of the specific species of yeast. Moreover, studies are showing that a specific yeast-derived compound may in fact be one of the strongest and most effective boosters of the immune system that we know of.
Coaching the Immune System to Succeed
That is correct! Science is confirming that beta glucans from yeast have a profound ability to improve the immune system. Beta glucans are polysaccharides that serve as structural components of cell walls. They occur in plants (like fiber-rich grains), algae and bacteria. Grain-derived beta glucans have beneficial effects in cholesterol and blood sugar markers of health; however, research has found that the effects of yeast-derived beta glucans on the immune system are special. Dubbed as ‘immune system trainers’, yeast-derived beta glucans have shown an ability to prime the immune system and increase its vigilance against invading pathogens. The key seems to be in the structural differences between yeast-derived beta glucans and those derived from other sources. Yeast beta glucans have what is structurally termed a 1,3 backbone with 1,6 side chain linkages. This structural arrangement with long side chains (termed as 1,3/1,6 beta glucans) make yeast beta glucans insoluble and allow them to confer unique immune benefits that other beta glucans do not possess.
While the initial research showing that yeast beta glucans have immune modulating effects dates to the 1940s, more recent science has yielded interesting information about how these compounds work in the body. The immune response in humans can be broken down into two basic aspects: the innate response and the adaptive response. The innate immune response is the initial response to pathogens and is comprised mainly of immune cells that envelop and kill the pathogen, including neutrophils, macrophages, and monocytes. The innate immune response in non-specific and is carried out as a first line of defense. After pathogens are processed through this stage, antigens from the pathogen are presented to T-cells and B-cells of the immune system for the development of a more specific adaptive immune response. The role of yeast beta glucans seems to be enhancing the robust nature of the first line of defense, the innate immune response, by priming and training the immune system to defend itself effectively and efficiently.
Firing Up the Immune System through Gut Health
It is widely accepted that more than 70% of the immune system is localized in the digestive tract, which is why gut health is so critical to immune health. Yeast beta glucans go to work in intestinal immune organs shortly after being consumed. Monocytes, macrophages, and dendritic cells of the immune system that are present in Peyer’s patches of the intestines phagocytose (or engulf) and process the insoluble 1,3/1,6 beta glucans. Over the next several days, these cells containing the processed, fragmented soluble particles are shuttled to the different immune organs of the body, including the spleen. The fragments are released and are then able to interact with cell receptors on various immune cells that modulate the innate immune response. Researchers generally believe that this fragmentation into biologically active beta glucan particles occurs over the first 3 to 5 days after ingestion. Immune cells slowly release these particles from days 5-10 with a decrease in release after 14 to 21 days.
Beta glucan particles then bind to receptors on neutrophils, monocytes, granulocytes, and NK cells of the immune system where they lead to a cascade of signaling events that serve to ultimately increase the efficiency and robustness of the innate immune response. Research has found that beta glucan-primed immune cells have an increased phagocytic capacity (to engulf pathogens), enhanced chemotaxis (improved ability to travel to a site of infection or attack) and improved oxidative burst (where free radicals are used by immune cells to damage pathogenic cells), an effect that strengthens the immune system.
Immune Protection for Healthy Aging
As we age, our immune system shows age-related declines in the ability to protect against external insults. Known as immune senescence, this results in immune cells functioning less efficiently over time. Yeast beta glucans serve as the ‘motivating force’ for these aging cells to get back into shape. Clinical research has found that older adults supplementing with yeast beta glucans during the winter months had a reduction in days they felt unwell and showed significant improvements in the function of the innate immune system, highlighted by an increased production of immune system chemicals versus those adults not taking beta glucans. Other benefits of yeast beta glucans in older adults were an increased number of circulating B cells, which are part of the adaptive immune response. As immune senescence (reduced immune function with age) is a key factor in the inability of older adults to fight off infections, it is likely that supplementing with 1,3/1,6 beta glucans from yeast can help revive an underperforming immune system, allowing it to flourish and perform like a star player once again. This ability of beta glucans to boost immune system health makes them special and certainly a natural ingredient worthy of consideration as a prime choice for elevating immune function year-round.
- De Marco Castro E, et al. Mol Nutr Food Res. 2021.
- Ciecierska A et al. Rocz Panstw Zakl Hig. 2019.
- Voidarou C et al. Foods. 2021.
- Fuller R et al. Nutrition. 2017
Tags: Yeast, beta glucans, immune, immunity, immunosenescence, innate immunity, adaptive immunity, immune cells, cytokines, monocytes, phagocytosis, macrophages, 1,3/1,6 beta glucans, granulocytes, NK cells, neutrophils, T cells, B cells, microbiome, probiotic