Nutritional Yeast to Help Prevent Common Childhood Infections

The amount of beta-glucan fiber in just a dusting of nutritional yeast a day is put to the test in a randomized, double-blind, placebo-controlled trial for the prevention of common childhood illnesses.

In 1989, the late Charles Janeway gave a presentation that was to revolutionize our understanding of the immune system. He proposed that we must have some ancient innate first line of defense. We had known about vaccinations for centuries and how our bodies can learn from past infections, but he figured that was not enough: Our body must have evolved some way to recognize foreign invaders the first time they invade. 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; we’re born with the ability to “recognize patterns of microbial structure.” For example, there’s a unique component of fungal cell walls called beta-glucan (β-glucan) that naturally stimulates our immune system. Our own cells don’t produce it, 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 include baker’s yeast, brewer’s yeast, and nutritional yeast, have that same molecular signature as beta-glucan. The drug industry is capitalizing on this “powerful immunostimulatory response” to develop new anti-infection, anticancer therapies, but does it have to be injected into the vein? What happens if you just eat some nutritional yeast? I discuss this in my video Best Food to Prevent Common Childhood Infections.

Our digestive tract is our largest point of contact with the outside world, with more surface area exposed than our lungs and skin put together, so it is not surprising that most of our immune cells are concentrated along the intestinal wall. They don’t just stay there, though. Once they’re tipped off to 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, for example, 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] β-glucan can be just the right solution.” You don’t know, of course, until you put it to the test. 

So, researchers performed a randomized, double-blind, placebo-controlled trial of about a half teaspoon of nutritional yeast worth of beta-glucan in children who suffered from repeated respiratory infections. As you can see at 3:17 in my video, 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 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 were provided. The only reason we cared about the lysozyme levels, though, was because we were hoping it would result in fewer infections, but there had never been any such studies…until now.

A randomized, double-blind, placebo-controlled trial was performed to see whether the beta-glucan in just a dusting of nutritional yeast a day would reduce the number of episodes of common childhood illnesses. “During the 12-week course of the study 85% of children in the placebo group experienced one or more episodes of infectious illness.” If you go to 4:19 in my video, I show this graphically: Eighty-five percent got ill in the sugar pill group, but taking just an 8th of a teaspoon of nutritional yeast 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 about three days, compared with closer to nine days 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,” too.

Nutritional yeast has also been found to be beneficial for marathon runners—see Preserving Immune Function in Athletes with Nutritional Yeast—and also for Stress-Induced Immune Suppression. What about the Benefits of Nutritional Yeast for Cancer? Chlorella and wakame may also help boost immunity, as you’ll learn in my videos Preserving Athlete Immunity with Chlorella and How to Boost Your Immune System with Wakame Seaweed, and so can produce, which I discuss in Using the Produce Aisle to Boost Immune Function.


Some should stay away from nutritional yeast, though: 

In health, 

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Dietary Cure for Hidradenitis Suppurativa

What is the role of dairy- and yeast-exclusion diets on arresting and reversing an inflammatory autoimmune disease?

A landmark study suggested that exposure to dietary yeast, like baker’s yeast, brewer’s yeast, and nutritional yeast, may worsen the course of Crohn’s disease, an autoimmune inflammatory bowel disease. The reason the researchers even thought to do the study was because Crohn’s patients tend to have elevated levels of antibodies to yeast, but Crohn’s is not the only autoimmune disease with increased yeast antibodies. The same has been found in lupus patients, found in rheumatoid arthritis, found in another joint disease called ankylosing spondylitis, found in autoimmune liver disease, and also found in autoimmune thyroid disease. So, might avoiding yeast help those conditions, too? They haven’t been put to the test, but hidradenitis suppurativa has. What is that? I discuss this in my video Dietary Cure for Hidradenitis Suppurativa.

Hidradenitis suppurativa can be a gruesome disease. It starts out with just pimples, typically along parts of the body where there are folds, such as the armpits, groins, buttocks, and under the breast. Then, painful nodules form that turn into abscesses and drain a thick, foul-smelling pus. And then? It gets even worse, forming active tunnels of pus inside your body.

And, it is not that rare. It has an estimated prevalence of about 1 to 4 percent, which is like 1 in 50. Clothes typically cover it up so it remains hidden, but you can often smell the pus oozing out of people. There are all sorts of surgical options and chemotherapy, but why did researchers even think to try diet for the condition? I mean, since Crohn’s is a disease of intestinal inflammation, you can see how a food you react to could make matters worse, but why a disease of armpit inflammation? Because there seems to be a link between hidradenitis suppurativa and Crohn’s disease. Having one may make you five times more likely to have the other, so there may be an “immunopathogenic link” between the two—they may share similar abnormal immune responses. Given that, if cutting yeast out of Crohn’s patients’ diets helps them, then maybe cutting it out of the diets of people with hidradenitis suppurativa might help them. A dozen patients with hidradenitis suppurativa were put on a diet that eliminated foods with yeast, like bread and beer, and they all got better, 12 out of 12. There was an “immediate stabilization of their clinical symptoms, and the skin lesions regressed,” that is, reversed, and went away within a year on the diet. Okay, but how do we know it was the yeast? By cutting out a food like pizza, you also may be cutting out a lot of dairy, and that also appears to help. Indeed, a dairy-free diet led to improvement in about five out of six patients.

See, those tunnels of pus are caused by the rupturing of the same kind of sebaceous glands that can cause regular acne. In hidradenitis suppurativa, however, they explode, and “[d]airy products contain 3 components that drive the process that blocks the duct [clogging your pores] and contributes to its leakage, rupture, and ultimate explosion.” First, there’s casein, which elevates IGF-1. (I have about a dozen videos on IGF-1.) Second, the whey and lactose, and third, the hormones in the milk itself—six hormones produced by the cow, her placenta, and mammary glands that end up in the milk. So, why not try cutting out dairy to see if things improve?

There is a whole series of nasty drugs you can use to try to beat back the inflammation, but as soon as you stop taking them, the disease can come roaring back. Even after extensive surgery, the disease comes back in 25 to 50 percent of cases, so we are desperate to research new treatment options. But, patients aren’t waiting. They’re getting together in online communities, sharing their trial and error though social media, and people have reported successes cutting out dairy and refined carbohydrates, like white flour and sugar. So, a dermatologist in New Hampshire decided to give dairy-free a try, and 83 percent of the hidradenitis suppurativa patients he tried it on started to get better. What’s more, he didn’t even try cutting the sugar and flour out of their diets. Now, he didn’t conduct a clinical trial or anything. He just figured why not give dairy-free a go? It’s not easy to conduct randomized, clinical, dietary interventions, but that doesn’t stop individual patients from giving things a try. I mean, you can understand why there have to be institutional review boards and the like when trying out new, risky drugs and surgeries, but if it’s just a matter of trying a switch from cow’s milk to soy milk, for example, why do they have to wait? “As patients search for an effective path to clearance [of this horrible disease], they need support and guidance to follow the most healthful diet available, free of dairy and highly processed sugar and flour. Nothing could be more natural.”

But what about the yeast? How do we know it was the yeast? In the study we discussed earlier, 8 of the 12 patients had just gone through surgery, so maybe that’s why they got so much better. It’s similar to when I hear that someone with cancer had gone through the conventional route of chemotherapy, surgery, and radiation before going to some questionable clinic and then attributes their cure to the wheatgrass colonics or whatever else they got. How do they know it wasn’t the chemo/surgery/radiation that saved them? Well, in this study, why do we suspect it was the yeast? Because not only did every single one of the patients get better, “all the patients demonstrated an immediate recurrence of skin lesions following accidental or voluntary consumption of beer or other foods” like bread. So, not only did the elimination of yeast result in “rapid stabilization” and “a slow, but complete, regression of the skin lesions within a year,” but, in every single case, within 24 to 48 hours of taking a little brewer’s yeast or other “yeast-containing foods,” BAM!—the symptoms were back. So, that’s why the researchers concluded a “simple exclusion diet could promote the resolution of the skin lesions involved in this disabling and [perhaps not so] rare disease.”

What was the response in the medical community to this remarkable, landmark study? “Why was there no mention of informed consent and ethics committee approval…?” Letter after letter to the editor of the journal complained that the researchers had violated the Declaration of Helsinki, which is like the Nuremburg Code or Geneva Convention to protect against involuntary human experimentation, and asked where was the institutional review board approval for this yeast-exclusion study? In response, the researchers simply replied that they had just told them to avoid a few foods. They had given them the choice: We can put you on drugs that can have side effects, such as liver problems, or you can try out this diet. “The patients preferred the diet.” Let’s not forget, I would add, that they were all cured!

Anyway, bottom line, by avoiding foods, like pizza, which contains both dairy and yeast, sufferers may be able to prevent the ravages of the disease.


This is the fourth and final installment of a video series on the role baker’s, brewer’s, and nutritional yeast may play in certain autoimmune diseases. If you missed any of the others, see:

For more on dairy hormones, see:

Check out our IGF-1 topic page if you’re unfamiliar with this cancer-promoting growth hormone, which I highlight in my video Animal Protein Compared to Cigarette Smoking.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Is Nutritional Yeast Healthy for Everyone?

Those with certain autoimmune diseases such as Crohn’s disease should probably not eat nutritional yeast.

Thousands of years ago, some yeast floated down into our flour and drinks, pleasing our palates, and we’ve been regularly exposed to it ever since. Yeast isn’t a problem for most people, but even non-disease-causing microbes could potentially trigger autoimmune diseases like Crohn’s disease in those who are susceptible because their finely tuned immune balance is somehow off. Maybe that’s why bakers have the highest Crohn’s disease mortality and, from a different data set, also have among the highest rates of Crohn’s disease, as you can see at 0:30 in my video Is Nutritional Yeast Healthy for Everyone? Perhaps a “hypersensitivity to baker’s yeast…may play a role in Crohn’s disease.”

If you take people with Crohn’s and remove from their diets the three foods to which they appear to have the most antibodies, in order to try to calm their disease, and then add those foods back, you can provoke the symptoms once again and re-stimulate the inflammation. So, for example, an anal fistula gets nice and dry off those foods, starts oozing again once the foods are back in the diet, and then the spigot’s turned back off when the foods are removed once more, as you can see (ew!) at 0:57 in my video.

However, without a control group, you can’t exclude the possibility of a powerful placebo effect. There hadn’t been any such randomized controlled trials until researchers came up with a brilliant design. They tested people with Crohn’s for antibodies to 16 different foods and then randomized the subjects into two groups. Both groups were told to avoid four foods, but one group was told to avoid the four foods they reacted most to, while the other group was told to avoid the foods they reacted least to. The group assignments were given in sealed envelopes, so no one knew who was in which group until the end. So, did it matter? Yes, more than twice the probability of major clinical improvement was seen in the group told to stay away from the four foods their blood reacted most to—but that wasn’t just yeast. In fact, the “exclusion of milk, pork, beef, and egg was most strongly associated with improvement,” leading the researchers to suggest that perhaps instead of doing fancy blood tests, we should just tell our patients to cut out meat and eggs and see how they do. This would be consistent with population studies that associate “diets high in animal fat” with an increased risk of inflammatory bowel diseases, as well as interventional studies showing that a plant-based diet, in which meat is cut down to about one serving every two weeks, can drop relapse rates as low as an extraordinary 8 percent over two years.

But, what about the whole yeast question? Can’t you just put some yeast up someone’s butt and see what happens? Why, yes! Yes, you can, and researchers have. Indeed, researchers tested rectal exposure to six different foods, including yeast, in Crohn’s disease patients. This was kind of like a skin prick test, but instead of pricking the skin, they pricked the inside of people’s rectums with various foods. You can see at 3:00 in my video the various prick sites for the different foods, and it’s clear that yeast gave the most significant reaction in Crohn’s patients.

It appears that baker’s yeast, which is the same yeast as brewer’s yeast and nutritional yeast, may indeed have disease-causing importance in Crohn’s disease, but the good news would then be that it “may be of therapeutic relevance.” If Crohn’s patients went on a yeast-free diet, would they feel better? You don’t know until you put it to the test.

In fact, that’s exactly what the original study linking yeast and Crohn’s disease suggested back in 1988. “A controlled trial of a yeast free diet for patients with Crohn’s disease may therefore be worth while.” Why did it take years before such a study was done? Well, who’s going to fund it? Big Soda Bread? Thankfully, there are charities like the National Association for Colitis and Crohn’s disease, willing to put up the (yeast-free) dough.

Nineteen patients with Crohn’s disease ate their regular diet for a month and were then switched to a yeast-exclusion diet. There was a significantly higher CDAI, Crohn’s Disease Activity Index, which assesses symptoms like abdominal pain and diarrhea, during the period when they were eating yeast, compared to the yeast-free period. So, there was worse disease activity with yeast than without. Okay, but what was this yeast-free diet? They didn’t just cut out bread and beer. The researchers switched people from dairy milk to soy milk and from white flour to whole wheat, for example. Just cutting out milk can sometimes help with inflammatory bowel disease, as you can see at 4:43 in my video.

So, with so many dietary changes, how do we know what role the yeast played? This is how we know what role the yeast played: After placing the subjects on the new yeast-free diet, they then challenged the Crohn’s sufferers with either a capsule of yeast or a placebo. A tiny amount of yeast, like giving them a quarter teaspoon of nutritional yeast a day, made them worse, suggesting “yeast may be important in the pathogenesis [disease process] of Crohn’s disease.”

Now, for the vast majority of people, yeast is not a problem, but in susceptible individuals, it may trigger an abnormal immune response in the gut. But, wait. I thought the paratuberculosis bug was considered a trigger for Crohn’s disease. Well, maybe infection with paraTB is what “induces a hypersensitivity response to dietary yeast.” Who knows? The bottom line is that people with Crohn’s disease should not go out of their way to add baker’s, brewer’s, or nutritional yeast to their diets.

I introduced this topic in Does Nutritional Yeast Trigger Crohn’s Disease?, then took a bit of a tangent with Is Candida Syndrome Real?. Next, I finish up this video series by talking about another autoimmune disease that appears to be affected: Dietary Cure for Hidradenitis Suppurativa.


For more on Crohn’s, see Preventing Crohn’s Disease with Diet and Dietary Treatment of Crohn’s Disease

And paratubercuwhat? See Does Paratuberculosis in Milk Trigger Type 1 Diabetes? and Does Paratuberculosis in Meat Trigger Type 1 Diabetes?

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In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: