The amount of beta-glucan fiber in just a dusting of nutritional yeast each day may be enough to change the course of our immune response to various pathogens, according to a study that put this substance to the test in a randomized, double-blind, placebo-controlled trial for the prevention of common childhood illnesses.
The findings reflect an understanding of immunity that began in 1989, when the late Charles Janeway gave a presentation that revolutionized our understanding of the immune system. Janeway had correctly theorized and described the workings of the innate immune system.
He proposed that the way our immune cells discriminate between self and “nonself”—that is, our own cells versus invading microbes—may arise from pattern recognition receptors. In other words, he proposed that we’re born with the ability to “recognize patterns of microbial structure.”
This is where nutritional yeast—a type of single-celled fungus—comes into play. There’s a unique component of fungal cell walls called beta-glucan that naturally stimulates our immune system. Our own cells don’t produce beta-glucan, but fungal pathogens such as candida do. Candida is a type of yeast that can cause serious blood infections, so it’s good if our immune system recognizes it right off the bat. Of course, you could stimulate the immune system by injecting candida into your veins, but then you also might die.
Luckily for us, non-disease-causing yeasts such as Saccharomyces cerevisiae, which is used to make baker’s yeast, brewer’s yeast, and nutritional yeast, have the same molecular signature as beta-glucan. The drug industry is capitalizing on this “powerful immunostimulatory response” to develop new anti-infection, anticancer therapies, and you don’t need to inject them to get the benefits.
Our digestive tract is our largest point of contact with the outside world. All the food from outside travels through this system, which has more surface area exposed than our lungs and skin put together. So it’s not surprising that most of our immune cells are concentrated along the intestinal wall. They don’t just stay there, though. Once they’re aware of what’s happening in the gut, they can go defend other parts of the body. That’s why you can give an oral cholera vaccine and end up with cholera-fighting immune cells in your salivary glands, pumping antibodies out into your saliva to protect against infection.
What if we sprinkled some nutritional yeast on our kids’ popcorn for a snack? Might that help marshal defenses throughout their bodies? Adults tend to get just a few colds a year, but the average schoolchild can come down with a cold every other month—and what can we really do about it? Modern medicine has little to offer for run-of-the-mill common colds. Nevertheless, doctors still commonly prescribe antibiotics, which can do more harm than good.
“Clearly, there is a need for effective, safe, and inexpensive treatment … [and] beta-glucan can be just the right solution,” wrote the authors of a study published in 2013.
The researchers of that study performed a randomized, double-blind, placebo-controlled trial using about half a teaspoon of nutritional yeast’s worth of beta-glucan in children who suffered from repeated respiratory infections. They reported in the Annals of Translational Medicine that after a month, they found a significant increase in salivary lysozyme levels compared with controls. Lysozyme is an important protective immune component of our eyes, nose, and mouth.
However, a larger follow-up study published in the same journal in 2014 reported the opposite findings, an apparent drop in salivary lysozyme levels. And, although the researchers claimed this was “accompanied by pronounced improvements in the general physical health of tested individuals,” no such data was provided. The only reason we cared about the lysozyme levels, though, was that we were hoping it would result in fewer infections, but there had never been any such studies … until 2016.
That’s when researchers published their findings in the Journal of Nutrition & Food Sciences. They conducted a randomized, double-blind, placebo-controlled trial to see whether the beta-glucan in just a dusting of nutritional yeast each day would reduce the number of episodes of common childhood illnesses.
“During the 12-week course of the study 85 percent of children in the placebo group experienced one or more episodes of infectious illness,” the study stated. Eighty-five percent became ill in the sugar pill group, but taking just an eighth of a teaspoon of nutritional yeast’s worth of beta-glucans or even just a 16th of a teaspoon’s worth appeared to cut illness rates in half. And those on the yeast who did come down with a cold only suffered for roughly three days, compared to the closer to nine days suffered in the placebo group.
The researchers concluded that by giving kids these yeast beta-glucans, we could “decrease the incidence and severity of infectious illness during the cold/flu season, alleviating some of the burden on parents of caring for sick children.”
Nutritional yeast has also been found to be beneficial for marathon runners, stress-induced immune suppression, and even for cancer, but that’s an article all on its own.
Michael Greger, MD, FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. He has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on “The Dr. Oz Show” and “The Colbert Report,” and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. This article was originally published on NutritionFacts.org.